Body Parts

ab
the muscles of the abdomen
 
abdomen
the cavity containing the major viscera; in mammals it is separated from the thorax by the diaphragm
 
abdomen
the region of the body of a vertebrate between the thorax and the pelvis
 
abdominal aorta
a branch of the descending aorta
 
abdominal external oblique muscle
a diagonally arranged abdominal muscle on either side of the torso
 
abdominal nerve plexus
a large plexus of sympathetic nerves in the abdomen behind the stomach
 
abducens muscle
the ocular muscle whose contraction turns the eyeball outward
 
abducens
a small motor nerve supplying the lateral rectus muscle of the eye
 
abductor
a muscle that draws a body part away from the median line
 
abomasum
the fourth compartment of the stomach of a ruminant; the one where digestion takes place
 
acanthion
the craniometric point at the anterior extremity of the intermaxillary suture
 
accessory cephalic vein
a vein that passes along the radial edge of the forearm and joins the cephalic vein near the elbow
 
accessory hemiazygos vein
a vein formed by the union of the 4th to 7th posterior intercostal veins; empties into the azygos vein
 
accessory nerve
arises from two sets of roots (cranial and spinal) that unite to form the nerve
 
accessory vertebral vein
a vein that accompanies the vertebral vein but passes through the foramen of the transverse process of the 7th cervical vertebra and empties into the brachiocephalic vein
 
accompanying vein
a vein accompanying another structure; a vein may accompany an artery in such a way that the arterial pulses aid venous return
 
acetabulum
the cup-shaped hollow in the hipbone into which the head of the femur fits to form a ball-and-socket joint
 
acinus
one of the small sacs or saclike dilations in a compound gland
 
acoustic meatus
either of the passages in the outer ear from the auricle to the tympanic membrane
 
acoustic nerve
a composite sensory nerve supplying the hair cells of the vestibular organ and the hair cells of the cochlea
 
acromial process
the outermost point of the spine of the shoulder blade
 
acrosome
a process at the anterior end of a sperm cell that produces enzymes to facilitate penetration of the egg
 
aculea
small spiny outgrowth on the wings of certain insects
 
aculeus
a sharp-pointed process especially a sting of a hymenopterous insect
 
aculeus
a stiff sharp-pointed plant process
 
acumen
a tapering point
 
Adam's apple
the largest cartilage of the larynx
 
adductor
a muscle that draws a body part toward the median line
 
adenohypophysis
the anterior lobe of the pituitary body; primarily glandular in nature
 
adhesion
a fibrous band of scar tissue that binds together normally separate anatomical structures
 
adipose tissue
a kind of body tissue containing stored fat that serves as a source of energy; it also cushions and insulates vital organs
 
adnexa
accessory or adjoining anatomical parts or appendages to an organ (especially of the embryo)
 
adrenal cortex
the cortex of the adrenal gland; secretes corticosterone and sex hormones
 
adrenal medulla
the medulla of the adrenal gland; secretes epinephrine
 
adrenal
either of a pair of complex endocrine glands situated near the kidney
 
adult tooth
any of the 32 teeth that replace the deciduous teeth of early childhood and (with luck) can last until old age
 
adventitia
an enveloping or covering membrane or layer of body tissue
 
afferent
a nerve that passes impulses from receptors toward or to the central nervous system
 
afterbirth
the placenta and fetal membranes that are expelled from the uterus after the baby is born
 
agnail
a loose narrow strip of skin near the base of a fingernail; tearing it produces a painful sore that is easily infected
 
agonist
a muscle that contracts while another relaxes
 
air bladder
an air-filled sac near the spinal column in many fishes that helps maintain buoyancy
 
air cell
a tiny sac for holding air in the lungs; formed by the terminal dilation of tiny air passageways
 
air sac
any of the membranous air-filled extensions of the lungs of birds
 
air sac
any of the thin-walled extensions of the tracheae of insects
 
airway
the passages through which air enters and leaves the body
 
ala
a wing of an insect
 
ala
a flat wing-shaped process or winglike part of an organism
 
albuginea
whitish tunic
 
allantois
the vascular fetal membrane that lies below the chorion and develops from the hindgut in many embryonic higher vertebrates (reptiles, birds and mammals)
 
allograft
tissue or organ transplanted from a donor of the same species but different genetic makeup; recipient's immune system must be suppressed to prevent rejection of the graft
 
alpha receptor
receptors postulated to exist on nerve cell membranes of the sympathetic nervous system in order to explain the specificity of certain agents that affect only some sympathetic activities (such as vasoconstriction and relaxation of intestinal muscles and contraction of smooth muscles)
 
alveolar arch
the part of the upper or lower jawbones in which the teeth are set
 
alveolar artery
a branch of the maxillary artery that supplies the alveolar process
 
alveolar bed
lung tissue densely packed with alveoli
 
alveolar point
craniometric point that is the most anterior point in the midline on the alveolar process of the maxilla
 
alveolar process
a ridge that forms the borders of the upper and lower jaws and contains the sockets of the teeth
 
alveolus
a bony socket in the alveolar ridge that holds a tooth
 
ambulacrum
one of the five areas on the undersurface of an echinoderm on which the tube feet are located
 
amnion
thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)
 
amniotic cavity
the fluid-filled cavity that surrounds the developing embryo
 
ampulla
the dilated portion of a canal or duct especially of the semicircular canals of the ear
 
amygdala
an almond-shaped neural structure in the anterior part of the temporal lobe of the cerebrum; intimately connected with the hypothalamus and the hippocampus and the cingulate gyrus; as part of the limbic system it plays an important role in motivation and emotional behavior
 
anal sphincter
the sphincter muscle of the anus
 
anastomotic vein
either of two communicating veins serving the brain
 
anatomical sphincter
a ring of muscle that contracts to close an opening
 
anatomical structure
a particular complex anatomical part of a living thing and its construction and arrangement
 
anconeous muscle
the muscle that extends the forearm and abducts the ulna in pronation of the wrist
 
angular artery
the terminal branch of the facial artery
 
angular vein
a short vein formed by the supraorbital vein and the supratrochlear vein and continuing as the facial vein
 
animal foot
the pedal extremity of vertebrates other than human beings
 
animal leg
the leg of an animal
 
animal tissue
the tissue in the bodies of animals
 
ankle
a gliding joint between the distal ends of the tibia and fibula and the proximal end of the talus
 
anklebone
the bone in the ankle that articulates with the leg bones to form the ankle joint
 
anlage
an organ in its earliest stage of development; the foundation for subsequent development
 
annualry
the third finger (especially of the left hand)
 
ANS
the part of the nervous system of vertebrates that controls involuntary actions of the smooth muscles and heart and glands
 
antagonist
a muscle that relaxes while another contracts
 
antagonistic muscle
(physiology) a muscle that opposes the action of another
 
antenna
one of a pair of mobile appendages on the head of e.g. insects and crustaceans; typically sensitive to touch and taste
 
anterior cardinal vein
a major drainage channel from the cephalic part of the body
 
anterior cerebral artery
one of two branches of the internal carotid artery; divides into two branches that serve (1) the thalamus and (2) parts of the frontal and parietal cortex
 
anterior cerebral vein
accompanies the anterior cerebral artery and empties into the basal vein
 
anterior crural nerve
one of a pair of nerves that originate from lumbar nerves and supply the muscles and skin of the anterior part of the thigh
 
anterior facial vein
a continuation of the angular vein; unites with the retromandibular vein before emptying into the internal jugular vein
 
anterior fontanelle
corresponds to the bregma when bones have ossified
 
anterior horn
one of the two roots of a spinal nerve that passes ventrally from the spinal cord and that consists of motor fibers
 
anterior jugular vein
arises below the chin from veins draining the lower face; joins the external jugular vein
 
anterior labial veins
veins from the labia majora to the external pudendal vein
 
anterior meningeal artery
branch of the anterior ethmoidal artery that supplies meninges in the anterior cranial fossa
 
anterior naris
either one of the two external openings to the nasal cavity in the nose
 
anterior serratus muscle
muscles that rotate the scapula and elevate the rib cage
 
anterior temporal artery
temporal artery that goes to the anterior part of the cerebral cortex of the temporal lobe
 
anterior vertebral vein
a vein that accompanies the ascending cervical artery and opens into the vertebral vein
 
anterior
a tooth situated at the front of the mouth
 
antler
deciduous horn of a member of the deer family
 
antrum
a natural cavity or hollow in a bone
 
anus
the excretory opening at the end of the alimentary canal
 
anvil
the ossicle between the malleus and the stapes
 
aorta
the large trunk artery that carries blood from the left ventricle of the heart to branch arteries
 
aortic arch
the part of the aorta that arches and turns downward
 
aortic orifice
the orifice from the lower left chamber of the heart to the aorta
 
aortic plexus
a plexus of lymph nodes in the lower portion of the abdominal aorta
 
aortic valve
a semilunar valve between the left ventricle and the aorta; prevents blood from flowing from the aorta back into the heart
 
apocrine gland
a large sweat gland that produces both a fluid and an apocrine secretion; in human beings located in hairy regions of the body
 
apodeme
ridge-like ingrowth of the exoskeleton of an arthropod that supports internal organs and provides attachment points for muscles
 
aponeurosis
any of the deeper and thicker fascia that attach muscles to bones; resemble flattened tendons
 
apophysis
(botany) a natural swelling or enlargement: at the base of the stalk or seta in certain mosses or on the cone scale of certain conifers
 
apophysis
(anatomy) a natural outgrowth or projection on an organ or body part such as the process of a vertebra
 
apparatus
(anatomy) a group of body parts that work together to perform a given function
 
apparatus urogenitalis
the system that includes all organs involved in reproduction and in the formation and voidance of urine
 
appendage
an external body part that projects from the body
 
appendage
a natural prolongation or projection from a part of an organism either animal or plant
 
appendicular artery
the branch of the ileocolic artery that supplies the vermiform appendix
 
appendicular skeleton
the part of the skeleton that includes the pectoral girdle and the pelvic girdle and the upper and lower limbs
 
appendicular vein
a vein that accompanies the appendicular artery and empties into the ileocolic vein
 
appendix
a vestigial process that extends from the lower end of the cecum and that resembles a small pouch
 
arachnoid
the middle of the 3 meninges
 
arch
a curved bony structure supporting or enclosing organs (especially the inner sides of the feet)
 
archenteron
central cavity of the gastrula; becomes the intestinal or digestive cavity
 
archipallium
the olfactory cortex of the cerebrum
 
arcuate artery of the kidney
curved arteries of the kidney
 
arcuate artery
curved artery in the foot
 
arcuate vein of the kidney
veins that receive blood from interlobular veins of kidney and rectal venules
 
arcus zygomaticus
the slender arch formed by the temporal process of the cheekbone that bridges to the zygomatic process of the temporal bone
 
arcus
a whitish deposit in the shape of an arc that is sometimes seen in the cornea
 
area 17 of Brodmann
the part of the occipital cortex that receives the fibers of the optic radiation from the lateral geniculate body and is the primary receptive area for vision
 
area of cardiac dullness
a triangular area of the front of the chest (determined by percussion); corresponds to the part of the heart not covered by the lungs
 
area
a part of an animal that has a special function or is supplied by a given artery or nerve
 
areola
small space in a tissue or body part such as the area between veins on a leaf or an insect's wing
 
areola
small circular area such as that around the human nipple or an inflamed area around a pimple or insect bite
 
areolar tissue
fibrous connective tissue with the fibers arranged in a mesh or net
 
areteria cervicalis
an artery that supplies the muscles of the neck
 
arista
bristlelike process near the tip of the antenna of certain flies
 
arm
a human limb; technically the part of the superior limb between the shoulder and the elbow but commonly used to refer to the whole superior limb
 
arm bone
a bone in the arm
 
armpit
the hollow under the arm where it is joined to the shoulder
 
arse
vulgar slang for anus
 
arse
the fleshy part of the human body that you sit on
 
arteria alveolaris inferior
the alveolar artery that goes through the mandibular canal to supply the lower teeth
 
arteria alveolaris superior
the alveolar artery that supplies the upper teeth
 
arteria ascendens
the branch of the ileocolic artery that supplies the ascending colon
 
arteria auricularis
artery that supplies blood to the ear
 
arteria axillaris
the part of the main artery of the arm that lies in the armpit and is continuous with the subclavian artery above and the brachial artery below
 
arteria basilaris
an unpaired artery; supplies the pons and cerebellum and the back part of the cerebrum and the inner ear
 
arteria brachialis
the main artery of the upper arm; a continuation of the axillary artery; bifurcates into the radial and ulnar arteries at the elbow
 
arteria buccalis
a branch of the maxillary artery that supplies blood to the buccinator muscle and the cheek
 
arteria bulbi penis
a branch of the internal pudendal artery of males that supplies the bulb of the penis
 
arteria bulbi vestibuli
a branch of the internal pudendal artery in females that supplies the bulb of the vestibule
 
arteria carotis
either of two major arteries of the neck and head; branches from the aorta
 
arteria celiaca
an artery that originates from the abdominal aorta just below the diaphragm and branches into the left gastric artery and the common hepatic artery and the splenic artery
 
arteria centralis retinae
a branch of the ophthalmic artery; enters the eyeball with the optic nerve
 
arteria cerebelli
an artery that supplies the cerebellum
 
arteria cerebri
any of the arteries supplying blood to the cerebral cortex
 
arteria choroidea
an artery that supplies the choroid plexus
 
arteria ciliaris
one of several arteries supplying the choroid coat of the eye
 
arteria circumflexa femoris
an artery that supplies the hip joint and thigh muscles
 
arteria circumflexa humeri
an artery that supplies the shoulder joint and shoulder muscles
 
arteria circumflexa ilium
an artery that supplies the lower abdominal walls and skin and the sartorius muscle
 
arteria circumflexa scapulae
an artery that serves the muscles of the shoulder and scapular area
 
arteria colica
arteries that supply blood to the colon
 
arteria communicans
any of three arteries in the brain that make up the circle of Willis
 
arteria coronaria
the artery that branches from the aorta to supply blood to the heart
 
arteria cystica
a branch of the hepatic artery; supplies the gall bladder and the surface of the liver
 
arteria digitalis
arteries in the hand and foot that supply the fingers and toes
 
arteria epigastrica
one of three arteries supplying the anterior walls of the abdomen
 
arteria ethmoidalis
a branch of the ophthalmic artery supplying structures in and around the nasal capsule
 
arteria facialis
an artery that originates in the external carotid and gives off branches that supply the neck and face
 
arteria femoralis
the chief artery of the thigh; a continuation of the external iliac artery
 
arteria gastrica breves
several small arteries branching off of the splenic artery and going to the greater curvature of the stomach
 
arteria gastrica sinistra
a branch of the celiac artery that supplies the lesser curvature of the stomach and the abdominal part of the esophagus
 
arteria gastrica
the arteries that supply the walls of the stomach
 
arteria glutes
branches of the internal iliac artery that supply the hip joint and gluteal region
 
arteria hepatica
arteries that supply the liver
 
arteria ileocolica
an artery that originates from the superior mesenteric artery and supplies the terminal part of the ileum and the cecum and the vermiform appendix and the ascending colon
 
arteria ileum
branch of the superior mesenteric artery that supplies the ileum
 
arteria iliaca
one of the large arteries supplying blood to the pelvis and legs
 
arteria iliolumbalis
an artery that originates in the internal iliac artery and supplies the pelvic muscles and bones
 
arteria infraorbitalis
an artery that originates from the maxillary artery and supplies structures below the orbit (from lower eyelid to upper lip)
 
arteria intercostalis
several arteries and supplying the intercostal spaces of the rib cage
 
arteria labialis inferior
an artery that is a branch of the facial artery that supplies the lower lip
 
arteria labialis superior
an artery that is a branch of the facial artery that supplies the upper lip
 
arteria labialis
an artery that is a branch of the facial artery that supplies the lips of the mouth
 
arteria lacrimalis
an artery that originates from the ophthalmic artery and supplies the lacrimal gland and rectal eye muscles and the upper eyelid and the forehead
 
arteria laryngea
either of two arteries that supply blood to the larynx
 
arteria lienalis
an artery that originates from the celiac trunk and supplies blood to the spleen
 
arteria lingualis
an artery originating from the external carotid artery and supplying the under side of the tongue
 
arteria lumbalis
one of four or five pairs of arteries that originate in the abdominal aorta and supply the lumbar vertebrae and the back muscles and abdominal wall
 
arteria maxillaris
either of two arteries branching from the external carotid artery and supplying structure of the face
 
arteria meningea
any of three arteries supplying the meninges of the brain and neighboring structures
 
arteria mesenterica
one of two branches of the aorta that pass between the two layers of the mesentery to the intestines
 
arteria metacarpea
dorsal and palmar arteries of the hand
 
arteria metatarsea
dorsal and plantar arteries to the metatarsal region of the foot
 
arteria musculophrenica
an artery that supplies the abdomen and intercostal muscles
 
arteria nutricia
an artery that supplies the medullary cavity of the long bone
 
arteria ophthalmica
a branch of the internal carotid artery that supplies the eye and neighboring structures
 
arteria ovarica
the artery that branches from the aorta and supplies blood to the ovaries
 
arteria palatina
one of several arteries supplying the face
 
arteria pancreatica
a branch of the splenic artery that supplies the pancreas
 
arteria perinealis
a branch of the internal pudendal artery that supplies superficial structures of the perineum
 
arteria poplitea
a continuation of the femoral artery that branches to supply the legs and feet
 
arteria pudenda
arteries supplying the external genital organs of humans
 
arteria pulmonalis
one of two arteries (branches of the pulmonary trunk) that carry venous blood from the heart to the lungs
 
arteria radialis
branch of the brachial artery beginning below the elbow and extending down the forearm around the wrist and into the palm
 
arteria rectalis
one of the arteries supplying the rectal area
 
arteria renalis
an artery originating from the abdominal aorta and supplying the kidneys and adrenal glands and ureters
 
arteria subclavia
either of two arteries that supply blood to the neck and arms
 
arteria temporalis intermedia
temporal artery that goes to the middle part of the cerebral cortex of the temporal lobe
 
arteria temporalis posterior
temporal artery that supplies the posterior part of the cortex of the temporal lobe
 
arteria testicularis
a branch of the aorta supplying the testicles
 
arteria ulnaris
large artery that branches from the brachial artery to supply the muscles of the forearm and wrist and hand
 
arteria uterina
a branch of the internal iliac artery that supplies the uterus and the upper part of the vagina
 
arteria vaginalis
a branch of the internal iliac that provides blood for the vagina and the base of the bladder and the rectum
 
arteria vertebralis
the first branch of the subclavian artery; divided into four parts
 
arteria
a blood vessel that carries blood from the heart to the body
 
arteriola
one of the small thin-walled arteries that end in capillaries
 
artery of the labyrinth
an artery that is a branch of the basilar artery that supplies the labyrinth
 
arthromere
any of the segments in the body of a jointed animal like an arthropod
 
articular muscle
a muscle that inserts directly onto the capsule of a joint
 
articulatio coxae
the ball-and-socket joint between the head of the femur and the acetabulum
 
articulatio cubiti
hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped
 
articulatio genus
hinge joint in the human leg connecting the tibia and fibula with the femur and protected in front by the patella
 
articulatio humeri
a ball-and-socket joint between the head of the humerus and a cavity of the scapula
 
articulatio plana
a freely moving joint in which the articulations allow only gliding motions
 
articulatio radiocarpea
a joint between the distal end of the radius and the proximal row of carpal bones
 
articulatio spheroidea
a freely moving joint in which a sphere on the head of one bone fits into a rounded cavity in the other bone
 
articulatio synovialis
a joint so articulated as to move freely
 
articulatio temporomandibularis
the joint between the head of the lower jawbone and the temporal bone
 
articulatio trochoidea
a freely moving joint in which movement is limited to rotation
 
articulatio
(anatomy) the point of connection between two bones or elements of a skeleton (especially if it allows motion)
 
articulator
a movable speech organ
 
articulatory system
the system of joints in the body
 
arytaenoid
either of two small cartilages at the back of the larynx to which the vocal folds are attached
 
ascending aorta
the ascending part of the aorta as it emerges from the left ventricle
 
ascending colon
the part of the large intestine that ascends from the cecum to the transverse colon
 
association area
cortical areas that are neither motor or sensory but are thought to be involved in higher processing of information
 
aster
star-shaped structure formed in the cytoplasm of a cell having fibers like rays that surround the centrosome during mitosis
 
asterion
the craniometric point at the junction of the lamboid suture and the occipitomastoid suture and the parietomastoid suture
 
astroglia
tissue consisting of large stellate neuroglial cells
 
ateria gastrica dextra
a branch of the hepatic artery that supplies the pyloric portion of the stomach on the lesser curvature
 
atheroma
a fatty deposit in the intima (inner lining) of an artery; can obstruct blood flow
 
athlete's heart
enlarged heart commonly found among athletes trained for endurance
 
atlas
the 1st cervical vertebra
 
atrial artery
the branch of the coronary artery that supplies the muscles of the atria
 
atrial auricle
a small conical pouch projecting from the upper anterior part of each atrium of the heart
 
atrioventricular node
a node of specialized heart muscle located in the septal wall of the right atrium; receives impulses from the sinoatrial node and transmits them to atrioventricular bundle
 
atrioventricular valve
either of two heart valves through which blood flows from the atria to the ventricles; prevents return of blood to the atrium
 
atrium
any chamber that is connected to other chambers or passageways (especially one of the two upper chambers of the heart)
 
atrium cordis
the upper chamber of each half of the heart
 
atrium dextrum
the right upper chamber of the heart that receives blood from the venae cavae and coronary sinus
 
atrium sinistrum
the left upper chamber of the heart that receives blood from the pulmonary veins
 
attic
informal terms for a human head
 
auditory apparatus
all of the components of the organ of hearing including the outer and middle and inner ears
 
auditory area
the cortical area that receives auditory information from the medial geniculate body
 
auditory center
the part of the brain (in a fold of the cerebral cortex of the temporal lobe on both sides of the brain) that receives impulses from the ear by way of the auditory nerve
 
auditory ossicle
ossicles of the middle ear that transmit acoustic vibrations from the eardrum to the inner ear
 
auditory system
the sensory system for hearing
 
auricle
the externally visible cartilaginous structure of the external ear
 
auricula
a pouch projecting from the top front of each atrium of the heart
 
auricular point
the craniometric point at the center of the opening of the external acoustic meatus
 
auricular vein
one of two veins serving the ear region
 
autograft
tissue that is taken from one site and grafted to another site on the same person
 
autonomic ganglion
any of the ganglia of the autonomic system whose unmyelinated fibers innervate the internal organs
 
autonomic plexus
a plexus of sympathetic and parasympathetic nerve fibers
 
awn
slender bristlelike appendage found on the bracts of grasses
 
axial muscle
a skeletal muscle of the trunk or head
 
axial skeleton
the part of the skeleton that includes the skull and spinal column and sternum and ribs
 
axillary node
any of the lymph glands of the armpit; fights infections in the neck and chest and arm regions
 
axillary vein
a continuation of the basilic vein and brachial vein that becomes the subclavian vein
 
axis
the 2nd cervical vertebra; serves as a pivot for turning the head
 
axolemma
outer membrane covering an axon
 
azygos vein
one of a system of veins that drain the thoracic and abdominal walls; arises as a continuation of the right ascending lumbar vein and terminates in the superior vena cava
 
baby tooth
one of the first temporary teeth of a young mammal (one of 20 in children)
 
back tooth
a tooth situated at the back of the mouth
 
back
the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
 
back
the posterior part of a human (or animal) body from the neck to the end of the spine
 
bag
mammary gland of bovids (cows and sheep and goats)
 
balancer
either of the rudimentary hind wings of dipterous insects; used for maintaining equilibrium during flight
 
ball
a more or less rounded anatomical body or mass
 
ball
one of the two male reproductive glands that produce spermatozoa and secrete androgens
 
band
a cord-like tissue connecting two larger parts of an anatomical structure
 
bandy leg
a leg bowed outward at the knee (or below the knee)
 
barbel
slender tactile process on the jaws of a fish
 
bare bone
bone stripped of flesh
 
baroreceptor
a sensory receptor that responds to pressure
 
Bartholin's gland
either of the two posterior vestibular glands that secrete a lubricating mucus; homologous to Cowper's gland in the male
 
basal ganglion
any of several masses of subcortical grey matter at the base of each cerebral hemisphere that seem to be involved in the regulation of voluntary movement
 
basal vein
a large vein passing along the medial surface of the temporal lobe and emptying into the great cerebral vein
 
basilar membrane
a membrane in the cochlea that supports the organ of Corti
 
basilic vein
a vein that drains the back of the hand and forearm and empties into the axillary vein
 
basivertebral vein
one of a number of veins draining the spongy substance of the vertebrae and emptying into the anterior internal vertebral venous plexus
 
bay window
slang for a paunch
 
beak
beaklike mouth of animals other than birds (e.g., turtles)
 
beak
horny projecting mouth of a bird
 
beak
informal terms for the nose
 
bear claw
claw of a bear; often used in jewelry
 
beard
a tuft or growth of hairs or bristles on certain plants such as iris or grasses
 
belly
the underpart of the body of certain vertebrates such as snakes or fish
 
belly
a protruding abdomen
 
beta receptor
receptors postulated to exist on nerve cell membranes of the sympathetic nervous system in order to explain the specificity of certain agents that affect only some sympathetic activities (such as vasodilation and increased heart beat)
 
betweenbrain
the posterior division of the forebrain; connects the cerebral hemispheres with the mesencephalon
 
biauriculate heart
a heart (as of mammals and birds and reptiles) having two auricles
 
biceps
any skeletal muscle having two origins (but especially the muscle that flexes the forearm)
 
biceps brachii
a muscle that flexes and supinates the forearm
 
bicuspid valve
valve with two cusps; situated between the left atrium and the left ventricle
 
bicuspid
a tooth having two cusps or points; located between the incisors and the molars
 
big toe
the first largest innermost toe
 
bile duct
a duct formed by the hepatic and cystic ducts; opens into the duodenum
 
biliary ductule
excretory ducts of the liver; empty into the hepatic ducts
 
bird's foot
the foot of a bird
 
birth canal
a passage in the uterus and vagina through which a fetus passes during vaginal birth
 
bladder sphincter
the sphincter muscle of the urinary bladder; made up of a thickened muscular layer of bladder around the urethral opening
 
bladder
a distensible membranous sac (usually containing liquid or gas)
 
blade
a broad flat body part (as of the shoulder or tongue)
 
blastocele
the fluid-filled cavity inside a blastula
 
blastoderm
a layer of cells on the inside of the blastula
 
blastopore
the opening into the archenteron
 
bleb
(pathology) an elevation of the skin filled with serous fluid
 
blind gut
the cavity in which the large intestine begins and into which the ileum opens
 
blister
(botany) a swelling on a plant similar to that on the skin
 
blood blister
blister containing blood or bloody serum usually caused by an injury
 
blood vessel
a vessel in which blood circulates
 
blowhole
the spiracle of a cetacean located far back on the skull
 
bob
a short or shortened tail of certain animals
 
bodily cavity
(anatomy) a natural hollow or sinus within the body
 
body
the body excluding the head and neck and limbs
 
bone marrow
the fatty network of connective tissue that fills the cavities of bones
 
bone
rigid connective tissue that makes up the skeleton of vertebrates
 
bonelet
a small bone; especially one in the middle ear
 
bony labyrinth
cavity in the petrous part of the temporal bone that contains the membranous labyrinth
 
boob
either of two soft fleshy milk-secreting glandular organs on the chest of a woman
 
book lung
organ in many arachnids containing many thin folds of membrane resembling the leaves of a book
 
bosom
a person's breast or chest
 
bowel
the part of the alimentary canal between the stomach and the anus
 
Bowman's capsule
thin double membrane surrounding the glomerulus of a nephron
 
brachial plexus
a network of nerves formed by cervical and thoracic spinal nerves and supplying the arm and parts of the shoulder
 
brachial vein
two veins in either arm that accompany the brachial artery and empty into the axillary vein
 
brachiocephalic vein
veins formed by the union of the internal jugular and subclavian veins
 
brain stem
the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamus
 
brain
that part of the central nervous system that includes all the higher nervous centers; enclosed within the skull; continuous with the spinal cord
 
braincase
the part of the skull that encloses the brain
 
branchia
respiratory organ of aquatic animals that breathe oxygen dissolved in water
 
branchial arch
one of the bony or cartilaginous arches on each side of the pharynx that support the gills of fishes and aquatic amphibians
 
branchial cleft
one of a series of slit openings in the pharynxes of fishes and aquatic amphibians through which water passes
 
breadbasket
an enlarged and muscular saclike organ of the alimentary canal; the principal organ of digestion
 
breast
the part of an animal's body that corresponds to a person's chest
 
breast
the front of the trunk from the neck to the abdomen
 
breastbone
the flat bone that articulates with the clavicles and the first seven pairs of ribs
 
bregma
the craniometric point at the junction of the sagittal and coronal sutures at the top of the cranium
 
bridge
the hard ridge that forms the upper part of the nose
 
bristle
a stiff hair
 
Brodmann's area
one of the cortical areas mapped out on the basis of its cytoarchitecture
 
bronchial artery
arteries that accompany the bronchioles
 
bronchial tube
either of the two main branches of the trachea
 
bronchial vein
veins serving the bronchi; empty into the azygos vein
 
bronchiole
any of the smallest bronchial ducts; ending in alveoli
 
brow
the part of the face above the eyes
 
brush
a bushy tail or part of a bushy tail (especially of the fox)
 
bubo
a lymph node that is inflamed and swollen because of plague or gonorrhea or tuberculosis
 
buccal cavity
the cavity between the jaws and the cheeks
 
buccinator muscle
a muscle that flattens the cheek and retracts the angle of the mouth
 
buccula
a fold of fatty tissue under the chin
 
bucktooth
a large projecting front tooth
 
buff
bare skin
 
bulb
a rounded dilation or expansion in a canal or vessel or organ
 
bulb
lower or hindmost part of the brain; continuous with spinal cord; (`bulb' is an old term for medulla oblongata)
 
bulbar conjunctiva
the part of the conjunctiva covering the anterior face of the sclera and the surface epithelium of the cornea
 
bull neck
a thick short powerful neck
 
bullethead
a head shaped like a bullet
 
bundle of His
a bundle of modified heart muscle that transmits the cardiac impulse from the atrioventricular node to the ventricles causing them to contract
 
burl
a large rounded outgrowth on the trunk or branch of a tree
 
bursa
a small fluid-filled sac located between movable parts of the body especially at joints
 
bursa omentalis
an isolated part of the peritoneal cavity that is dorsal to the stomach
 
bust
the chest of a woman
 
buttock
either of the two large fleshy masses of muscular tissue that form the human rump
 
button
a female sexual organ homologous to the penis
 
bypass
a surgically created shunt (usually around a damaged part)
 
cakehole
informal terms for the mouth
 
calamus
the hollow spine of a feather
 
calcaneus
the largest tarsal bone; forms the human heel
 
calcarine fissure
a sulcus in the mesial surface of the occipital lobe of the cerebrum
 
calf bone
the outer and thinner of the two bones of the human leg between the knee and ankle
 
calf
the muscular back part of the shank
 
caliculus
a small cup-shaped structure (as a taste bud or optic cup or cavity of a coral containing a polyp)
 
callus
(botany) an isolated thickening of tissue, especially a stiff protuberance on the lip of an orchid
 
calvaria
the dome of the skull
 
canal of Schlemm
a circular canal in the eye that drains aqueous humor from the anterior chamber of the eye into the anterior ciliary veins
 
canal
a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance
 
canaliculus
a small canal or duct as in some bones and parts of plants
 
canalis cervicis uteri
a spindle-shaped canal extending from the uterus to the vagina
 
canalis inguinalis
oblique passage through the lower abdominal wall; in males it is the passage through which the testes descend into the scrotum and it contains the spermatic cord; in females it transmits the round ligament of the uterus
 
canalis vertebralis
the canal in successive vertebrae through which the spinal cord passes
 
canine
one of the four pointed conical teeth (two in each jaw) located between the incisors and the premolars
 
cannon bone
greatly developed metatarsal or metacarpal bone in the shank or cannon part of the leg in hoofed mammals
 
cannon
lower part of the leg extending from the hock to the fetlock in hoofed mammals
 
capillary bed
a layer of tissue densely packed with capillaries
 
capillary vein
a minute vein continuous with a capillary
 
capillary
any of the minute blood vessels connecting arterioles with venules
 
capitate
the wrist bone with a rounded head shape that articulates with the 3rd metacarpus
 
capsule
a structure that encloses a body part
 
caput
the upper part of the human body or the front part of the body in animals; contains the face and brains
 
cardia
the opening into the stomach and that part of the stomach connected to the esophagus
 
cardiac muscle
the muscle tissue of the heart; adapted to continued rhythmic contraction
 
cardiac plexus
a plexus of nerves supplying the heart and nearby structures
 
cardiac sphincter
the valve between the distal end of the esophagus and the stomach; the physiological sphincter at the esophagogastric junction
 
cardiac valve
a valve to control one-way flow of blood
 
cardinal vein
any of the major venous channels in primitive adult vertebrates and in embryos of higher vertebrates
 
cardiovascular system
the organs and tissues involved in circulating blood and lymph through the body
 
carina
any of various keel-shaped structures or ridges such as that on the breastbone of a bird or that formed by the fused petals of a pea blossom
 
carina fornicis
ridge on the lower surface of the fornix of the brain
 
carnassial tooth
the last upper premolar and first lower molar teeth of a carnivore; having sharp edges for cutting flesh
 
carotid body
a chemoreceptor located near the bifurcations of the carotid arteries; monitors oxygen content of the blood and helps control respiration
 
carotid plexus
a plexus of nerves surrounding the internal carotid artery
 
carpal tunnel
a passageway in the wrist through which nerves and the flexor muscles of the hands pass
 
carpal
any of the eight small bones of the wrist of primates
 
cartilage bone
any bone that develops within cartilage rather than a fibrous tissue
 
cartilage
tough elastic tissue; mostly converted to bone in adults
 
cartilaginous structure
body structure given shape by cartilage
 
cartilaginous tube
a duct with cartilaginous walls
 
caruncle
an outgrowth on a plant or animal such as a fowl's wattle or a protuberance near the hilum of certain seeds
 
cauda
any taillike structure
 
caudal appendage
tail especially of a mammal posterior to and above the anus
 
caudal fin
the tail of fishes and some other aquatic vertebrates
 
caudal vertebra
one of 4 vertebrae in the human coccyx
 
caudate
a tail-shaped basal ganglion located in a lateral ventricle of the brain
 
caul
the inner membrane of embryos in higher vertebrates (especially when covering the head at birth)
 
caul
part of the peritoneum attached to the stomach and to the colon and covering the intestines
 
cauliflower ear
an auricle deformed by injury; common among boxers
 
cavernous sinus
either of a pair of large venous sinuses in the cranial cavity
 
cell membrane
a thin membrane (a double layer of lipids) enclosing the cytoplasm of a cell; proteins in the membrane control passage of ions (like sodium or potassium or calcium) in and out of the cell
 
cell nucleus
a part of the cell containing DNA and RNA and responsible for growth and reproduction
 
cell organ
a specialized part of a cell; analogous to an organ
 
cellulite
lumpy deposits of body fat especially on women's thighs etc.
 
celom
a cavity in the mesoderm of an embryo that gives rise in humans to the pleural cavity and pericardial cavity and peritoneal cavity
 
center
a cluster of nerve cells governing a specific bodily process
 
central gyrus
either of two gyri on either side of the central sulcus
 
central vein of retina
vein formed by the union of the retinal veins; accompanies central arteries of the retina in the optic nerve
 
central vein of suprarenal gland
a single draining vein; on the right it empties into the inferior vena cava; on the left it empties into the left renal vein
 
central veins of liver
terminal branches of the hepatic veins that lie in the hepatic lobules and receive blood from the liver sinusoids
 
centriole
one of a pair of small cylindrical cell organelles near the nucleus in animal cells; composed of nine triplet microtubules and form the asters during mitosis
 
centromere
a specialized condensed region of each chromosome that appears during mitosis where the chromatids are held together to form an X shape
 
centrum
the main body of a vertebra
 
cephalic vein
a large vein of the arm that empties into the axillary vein
 
ceras
one of the often brightly colored and branching hornlike structures on the back of the nudibranch (and other related mollusks) that serve as gills
 
cere
the fleshy, waxy covering at the base of the upper beak of some birds
 
cerebellar hemisphere
either of two lateral lobes of the cerebellum
 
cerebellar vein
the veins draining the cerebellum
 
cerebellum
a major division of the vertebrate brain; situated above the medulla oblongata and beneath the cerebrum in humans
 
cerebral cortex
the layer of unmyelinated neurons (the grey matter) forming the cortex of the cerebrum
 
cerebral hemisphere
either half of the cerebrum
 
cerebral peduncle
a bundle of myelinated neurons joining different parts of the brain
 
cerebral vein
any of several veins serving the cerebral hemispheres of the brain
 
cerebrum
anterior portion of the brain consisting of two hemispheres; dominant part of the brain in humans
 
cervical glands
mucus-secreting glands in the mucosa of the uterine cervix
 
cervical nerve
any of eight pairs of spinal nerves emerging from the cervical section of the spinal cord
 
cervical plexus
a nerve plexus lying beneath the sternocleidomastoid muscle
 
cervical vein
a vein that accompanies an artery of the same name
 
cervical vertebra
one of 7 vertebrae in the human spine located in the neck region
 
cervix
necklike opening to the uterus
 
cervix
the part of an organism (human or animal) that connects the head to the rest of the body
 
chaeta
a stiff chitinous seta or bristle especially of an annelid worm
 
chalaza
one of two spiral bands of tissue connecting the egg yolk to the enclosing membrane at either end of the shell
 
chamber
an enclosed volume in the body
 
cheek
either side of the face below the eyes
 
cheek pouch
a membranous pouch inside the mouth of many rodents (as a gopher)
 
cheekbone
the arch of bone beneath the eye that forms the prominence of the cheek
 
chela
a grasping structure on the limb of a crustacean or other arthropods
 
chelicera
either of the first pair of fang-like appendages near the mouth of an arachnid; often modified for grasping and piercing
 
chemoreceptor
a sensory receptor that responds to chemical stimuli
 
chest cavity
the cavity in the vertebrate body enclosed by the ribs between the diaphragm and the neck and containing the lungs and heart
 
chest
the part of the human torso between the neck and the diaphragm or the corresponding part in other vertebrates
 
chiasm
an intersection or crossing of two tracts in the form of the letter X
 
chiasma opticum
the crossing of the optic nerves from the two eyes at the base of the brain
 
chin
the protruding part of the lower jaw
 
chine
backbone of an animal
 
chondriosome
an organelle containing enzymes responsible for producing energy
 
chop
a jaw
 
chopper
informal terms for a human `tooth'
 
chordamesoderm
the area of mesoderm that forms the notochord
 
chorioallantoic membrane
the very vascular fetal membrane composed of the fused chorion and adjacent wall of the allantois
 
chorion
the outermost membranous sac enclosing the embryo in higher vertebrates (reptiles, birds and mammals)
 
chorionic villus
one of the tiny villi that stick out of the fetal chorion and combine with the mother's uterine tissue to form the placenta
 
choroid plexus
a vascular plexus of the cerebral ventricles that regulate intraventricular pressure
 
choroid vein
either of two veins serving the choroid coat of the eye
 
choroid
a highly vascular membrane in the eye between the retina and the sclera; a dark pigmentation minimizes the scattering of light inside the eye
 
ciliary body
the part of the tunic of the eye between the choroid coat and the iris
 
ciliary veins
small veins coming from the ciliary body
 
cilium
a hairlike projection from the surface of a cell; provides locomotion in free-swimming unicellular organisms
 
cingulate gyrus
a long curved structure on the medial surface of the cerebral hemispheres; the cortical part of the limbic system
 
cingulum
(anatomy) an encircling structure (as the ridge around the base of a tooth)
 
circle of Willis
a ring of arteries at the base of the brain
 
circumflex artery
any of several paired curving arteries
 
circumflex femoral vein
either of two veins that accompany arteries of the same name serving the hip and thigh
 
circumflex iliac vein
accompanies the artery of the same name
 
circumflex vein
any of several curved parallel veins accompanying arteries of the same name
 
cirrus
a slender flexible animal appendage as on barnacles or crinoids or many insects; often tactile
 
cistern
a sac or cavity containing fluid especially lymph or cerebrospinal fluid
 
clapper
a mobile mass of muscular tissue covered with mucous membrane and located in the oral cavity
 
claustrum
a layer of grey matter in the brain adjacent to the lenticular nucleus
 
clavicle
bone linking the scapula and sternum
 
claw
sharp curved horny process on the toe of a bird or some mammals or reptiles
 
claw
a bird's foot
 
cleavage
the line formed by a groove between two parts (especially the separation between a woman's breasts)
 
clenched fist
a hand with the fingers clenched in the palm (as for hitting)
 
clitoral vein
veins that serve the clitoris
 
cloaca
(zoology) the cavity (in birds, reptiles, amphibians, most fish, and monotremes but not mammals) at the end of the digestive tract into which the intestinal, genital, and urinary tracts open
 
cloven foot
a hoof divided into two parts at its distal extremity (as of ruminants or swine)
 
CNS
the portion of the vertebrate nervous system consisting of the brain and spinal cord
 
cobblers
a man's testicles (from Cockney rhyming slang: cobbler's awl rhymes with ball)
 
coccygeal nerve
the lowest pair of spinal nerves
 
coccygeal plexus
a small plexus formed by the fifth sacral and coccygeal nerves
 
coccyx
the end of the vertebral column in humans and tailless apes
 
cochlea
the snail-shaped tube (in the inner ear coiled around the modiolus) where sound vibrations are converted into nerve impulses by the organ of Corti
 
cock
obscene terms for penis
 
cockscomb
the fleshy red crest on the head of the domestic fowl and other gallinaceous birds
 
coelenteron
the saclike body cavity of a coelenterate
 
colic vein
vein serving the large intestine
 
colon
the part of the large intestine between the cecum and the rectum; it extracts moisture from food residues before they are excreted
 
column
any tubular or pillar-like supporting structure in the body
 
comb
ciliated comb-like swimming plate of a ctenophore
 
comb-plate
a locomotor organ consisting of a row of strong cilia whose bases are fused
 
commissure
a bundle of nerve fibers passing from one side to the other of the brain or spinal cord
 
common cardinal vein
the major return channels to the heart; formed by anastomosis of the anterior and posterior cardinal veins
 
common carotid
runs upward in the neck and divides into the external and internal carotid arteries
 
common facial vein
vein formed by union of facial vein and the retromandibular vein and emptying into the jugular vein
 
common iliac artery
terminal branches of the abdominal aorta
 
common iliac vein
formed by the internal and external iliac veins; unites with its fellow from the opposite side of the body to form the inferior vena cava
 
compound eye
in insects and some crustaceans: composed of many light-sensitive elements each forming a portion of an image
 
concha
(anatomy) a structure that resembles a shell in shape
 
condylar process
the condyle of the ramus of the mandible that articulates with the skull
 
condyle
a round bump on a bone where it forms a joint with another bone
 
condylion
the craniometric point at the tip of the mandibular condyle
 
conjunctiva
a transparent lubricating mucous membrane that covers the eyeball and the under surface of the eyelid
 
conjunctival layer of eyelids
the part of the conjunctiva lining the posterior surface of the eyelids; continuous with the bulbar conjunctiva
 
conjunctival veins
veins draining the conjunctiva
 
conk
informal term for the nose
 
connective tissue
tissue of mesodermal origin consisting of e.g. collagen fibroblasts and fatty cells; supports organs and fills spaces between them and forms tendons and ligaments
 
conodont
the tiny fossil cone-shaped tooth of a primitive vertebrate of order Conodonta
 
contractile organ
a bodily organ that contracts
 
convolution of Broca
the motor speech center in the left hemisphere of the brain in most people
 
convolution
a convex fold or elevation in the surface of the brain
 
cornea
the transparent dome-shaped anterior portion of the outer covering of the eye; it covers the iris and pupil and is continuous with the sclera
 
cornu
(anatomy) any structure that resembles a horn in shape
 
corona
(anatomy) any structure that resembles a crown in shape
 
coronal suture
the suture between the parietal and frontal bones of the skull
 
coronary sinus
a short sinus receiving most of the veins of the heart; empties into the right atrium
 
coronet
margin between the skin of the pastern and the horn of the hoof
 
coronion
the craniometric point at the tip of the coronoid process of the mandible
 
coronoid process of the mandible
the coronoid process that provides an attachment for the temporal muscle
 
coronoid process
a sharp triangular process projecting from a bone
 
corpus callosum
a broad transverse nerve tract connecting the two cerebral hemispheres
 
corpus geniculatum laterale
a neural structure that serves as a processing station on the way from the retina to the occipital lobe of the cerebral cortex
 
corpus geniculatum mediale
a neural structure that serves as the last of a series of processing centers along the auditory pathway from the cochlea to the temporal lobe of the cerebral cortex
 
corpus luteum
yellow endocrine tissue that forms in a ruptured Graafian follicle following the release of an ovum; it degenerates after a few days unless pregnancy has begun
 
corpus mamillare
one of two small round structures on the undersurface of the brain that form the terminals of the anterior arches of the fornix
 
corpus sternum
the large central part of the breastbone
 
corpus striatum
a striped mass of white and grey matter located in front of the thalamus in each cerebral hemisphere; consists of the caudate nucleus and the lenticular nucleus
 
cortex
the tissue forming the outer layer of an organ or structure in plant or animal
 
cortex
the tissue that surrounds the lens nucleus
 
cortical area
any of various regions of the cerebral cortex
 
corticospinal tract
any of the important motor nerves on each side of the central nervous system that run from the sensorimotor areas of the cortex through the brainstem to motor neurons of the cranial nerve nuclei and the ventral root of the spinal cord
 
costa
a riblike part of a plant or animal (such as a middle rib of a leaf or a thickened vein of an insect wing)
 
costa
any of the 12 pairs of curved arches of bone extending from the spine to or toward the sternum in humans (and similar bones in most vertebrates)
 
costal cartilage
the cartilages that connect the sternum and the ends of the ribs; its elasticity allows the chest to move in respiration
 
costal groove
groove between the ribs where the nerves and blood vessels are
 
costoaxillary vein
one of several veins connecting intercostal veins with the lateral thoracic vein or the thoracoepigastric vein
 
countenance
the human face (`kisser' and `smiler' and `mug' are informal terms for `face' and `phiz' is British)
 
cowl muscle
either of two flat triangular muscles of the shoulder and upper back that are involved in moving the shoulders and arms
 
Cowper's gland
either of two glands that discharge a component of seminal fluid into the urethra; homologous to Bartholin's gland in the female
 
cranial cavity
the cavity enclosed by the cranium
 
cranial nerve
any of the 12 paired nerves that originate in the brain stem
 
cranial orbit
the bony cavity in the skull containing the eyeball
 
craniometric point
a landmark on the skull from which craniometric measurements can be taken
 
craw
a pouch in many birds and some lower animals that resembles a stomach for storage and preliminary maceration of food
 
crazy bone
a point on the elbow where the ulnar nerve passes near the surface; a sharp tingling sensation results when the nerve is knocked against the bone
 
crest
a showy growth of e.g. feathers or skin on the head of a bird or other animal
 
crotaphion
the tip of the greater wing of the sphenoid bone
 
crotch
external sex organ
 
croup
the part of an animal that corresponds to the human buttocks
 
crus
the leg from the knee to foot
 
crystalline lens
biconvex transparent body situated behind the iris in the eye; its role (along with the cornea) is to focus light on the retina
 
ctenidium
comb-like respiratory structure serving as the gill of certain mollusks
 
cubital nerve
a nerve running along the inner side of the arm and passing near the elbow; supplies intrinsic muscles of the hand and the skin of the medial side of the hand
 
cubitus
the arm from the elbow to the fingertips
 
cuboid bone
the cube shaped bone on the outer side of the tarsus
 
cuneiform bone
a wrist bone that articulates with the pisiform and hamate and lunate bones
 
cunt
obscene terms for female genitals
 
cupule
a sucker on the feet of certain flies
 
cusp
a thin triangular flap of a heart valve
 
cutaneous vein
one of a number of veins in the subcutaneous tissue that empty into deep veins
 
cuticle
the dead skin at the base of a fingernail or toenail
 
cutis
a natural protective body covering and site of the sense of touch
 
cyst
a small anatomically normal sac or bladderlike structure (especially one containing fluid)
 
cystic vein
vein that drains the gallbladder
 
cytoskeleton
a microscopic network of actin filaments and microtubules in the cytoplasm of many living cells that gives the cell shape and coherence
 
cytostome
mouth of a protozoan
 
dacryocyst
either of the two dilated ends of the lacrimal ducts at the nasal ends of the eyes that fill with tears secreted by the lacrimal glands
 
dacryon
the craniometric point at the junction of the anterior border of the lacrimal bone with the frontal bone
 
dactyl
a finger or toe in human beings or corresponding body part in other vertebrates
 
decidua
the epithelial tissue of the endometrium
 
deep middle cerebral vein
accompanies the middle cerebral artery deep in the Sylvian fissure; empties into the basal vein
 
deep temporal vein
temporal veins that empty into the pterygoid plexus
 
deltoid eminence
a bump on the outside of the humerus where the deltoid muscle attaches
 
deltoid
a large triangular muscle covering the shoulder joint and serving to abduct and flex and extend and rotate the arm
 
dentate nucleus
a large laminar nucleus of grey matter within the white matter of each cerebral hemisphere
 
denticle
small pointed ridge on the exoskeleton of an arthropod
 
dentin
bone (calcified tissue) surrounding the pulp cavity of a tooth
 
depressor
any skeletal muscle that draws a body part down
 
depressor
any nerve whose activity tends to reduce the activity or tone of the body part it serves
 
descending aorta
the descending part of the aorta that branches into the thoracic and abdominal aortae
 
descending colon
the part of the large intestine that descends from the transverse colon to the sigmoid colon
 
dewlap
a hanging fold of loose skin on an elderly person's neck
 
diaphragm
(anatomy) a muscular partition separating the abdominal and thoracic cavities; functions in respiration
 
diaphysis
the main (mid) section of a long bone
 
digestive gland
any gland having ducts that pour secretions into the digestive tract
 
digestive system
the system that makes food absorbable into the body
 
digital vein
one of the veins serving the fingers or toes
 
dilator
a muscle or nerve that dilates or widens a body part
 
diploic vein
one of the veins serving the spongy part of the cranial bones
 
dock
the solid bony part of the tail of an animal as distinguished from the hair
 
dorsal fin
unpaired median fin on the backs of fishes and some other aquatic vertebrates that help to maintain balance
 
dorsal horn
one of two roots of a spinal nerve that passes dorsally from the spinal cord and that consists of sensory fibers
 
dorsal scapular vein
vein that is a tributary of the subclavian vein or external jugular vein and accompanies the descending scapular artery
 
dorsal vertebra
one of 12 vertebrae in the human vertebral column; thoracic vertebrae extend from the seventh cervical vertebra down to the first lumbar vertebra
 
dorsum
the back of the body of a vertebrate or any analogous surface (as the upper or outer surface of an organ or appendage or part)
 
duct gland
a gland that secretes externally through a duct
 
ductless gland
any of the glands of the endocrine system that secrete hormones directly into the bloodstream
 
ductule
a very small duct
 
ductus arteriosus
a blood vessel in a fetus that bypasses pulmonary circulation by connecting the pulmonary artery directly to the ascending aorta; normally closes at birth
 
ductus deferens
a duct that carries spermatozoa from the epididymis to the ejaculatory duct
 
dug
an udder or breast or teat
 
duodenum
the part of the small intestine between the stomach and the jejunum
 
dura
the outermost (and toughest) of the 3 meninges
 
ear
the sense organ for hearing and equilibrium
 
ear lobe
the fleshy pendulous part of the external human ear
 
eardrum
the membrane in the ear that vibrates to sound
 
eccrine gland
a small sweat gland that produces only a fluid; restricted to the human skin
 
ectoblast
the outer germ layer that develops into skin and nervous tissue
 
effector
an organ (a gland or muscle) that becomes active in response to nerve impulses
 
efferent
a nerve that conveys impulses toward or to muscles or glands
 
ejaculatory duct
a part of the seminal duct formed by the duct from the seminal vesicle and the vas deferens; passes through the prostate gland
 
elastic tissue
connective tissue consisting chiefly of elastic fibers found in the dermis of the skin and in the walls of veins and arteries and in some tendons and ligaments
 
elbow
the joint of a mammal or bird that corresponds to the human elbow
 
elbow bone
the inner and longer of the two bones of the human forearm
 
elytron
either of the horny front wings in beetles and some other insects which cover and protect the functional hind wings
 
embryonic tissue
tissue in an embryo
 
eminence
a protuberance on a bone especially for attachment of a muscle or ligament
 
emissary vein
one of several connecting veins in the scalp and head that drain blood from sinuses in the dura mater to veins outside the skull
 
enation
a natural projection or outgrowth from a plant body or organ
 
end organ
a specialized structure at the peripheral end of some motor or sensory nerve fibers
 
endoblast
the inner germ layer that develops into the lining of the digestive and respiratory systems
 
endocardium
the membrane that lines the cavities of the heart and forms part of the heart valves
 
endocranium
membrane lining the inside of the skull
 
endocrine system
the system of glands that produce endocrine secretions that help to control bodily metabolic activity
 
endometrium
(pregnancy) the mucous membrane that lines the uterus; thickens under hormonal control and (if pregnancy does not occur) is shed in menstruation; if pregnancy occurs it is shed along with the placenta at parturition
 
endoneurium
delicate connective tissue around individual nerve fibers in nerve
 
endoskeleton
the internal skeleton; bony and cartilaginous structure (especially of vertebrates)
 
endosteum
vascular membrane that lines the inner surface of long bones
 
endothelium
an epithelium of mesoblastic origin; a thin layer of flattened cells that lines the inside of some body cavities
 
endplate
the flattened end of a motor neuron that transmits neural impulses to a muscle
 
energid
a biological unit consisting of a nucleus and the body of cytoplasm with which it interacts
 
enteroceptor
any receptor that responds to stimuli inside the body
 
enteron
the alimentary canal (especially of an embryo or a coelenterate)
 
entomion
the craniometric point at the tip of the angular part of the parietal bone that articulates with the temporal bone
 
entrails
internal organs collectively (especially those in the abdominal cavity)
 
ependyma
thin epithelial membrane lining the ventricles of the brain and the spinal cord canal
 
epicanthic fold
a vertical fold of skin over the nasal canthus; typical for many east Asian peoples; sometimes occurs in Down's syndrome
 
epicardia
the short part of the esophagus extending downward from the diaphragm to the stomach
 
epicardium
the innermost of the two layers of the pericardium
 
epicondyle
a projection on a bone above a condyle serving for the attachment of muscles and ligaments
 
epididymis
a convoluted tubule in each testis; carries sperm to vas deferens
 
epigastric fossa
a slight depression in the midline just below the sternum (where a blow can affect the solar plexus)
 
epigastric vein
veins serving the anterior walls of the abdomen
 
epigastrium
the region lying on or over the stomach (just below the sternum)
 
epiglottis
a flap of cartilage that covers the windpipe while swallowing
 
epiphysis
the end of a long bone; initially separated from the main bone by a layer of cartilage that eventually ossifies so the parts become fused
 
epiphysis
a small endocrine gland in the brain; situated beneath the back part of the corpus callosum; secretes melatonin
 
episcleral veins
small veins in the sclera near the corneal margin; empty into the anterior ciliary veins
 
epithelial tissue
membranous tissue covering internal organs and other internal surfaces of the body
 
erectile organ
an organ containing erectile tissue
 
erectile tissue
vascular tissue capable of filling with blood and becoming rigid
 
erogenous zone
any area of the body especially sensitive to sexual stimulation
 
esophageal veins
small veins from the esophagus emptying into the brachiocephalic vein or the azygos veins
 
esophagus
the passage between the pharynx and the stomach
 
ethmoid sinus
a sinus of the meatuses of the nasal cavity (behind the bridge of the nose)
 
ethmoid
one of the eight bones of the cranium; a small bone filled with air spaces that forms part of the eye sockets and the nasal cavity
 
ethmoidal vein
veins that drain the ethmoidal sinuses and empty into the superior ophthalmic vein
 
Eustachian tube
either of the paired tubes connecting the middle ears to the nasopharynx; equalizes air pressure on the two sides of the eardrum
 
excrescence
(pathology) an abnormal outgrowth or enlargement of some part of the body
 
excretory organ
an organ that separates waste substances from the blood and discharges them
 
exoskeleton
the exterior protective or supporting structure or shell of many animals (especially invertebrates) including bony or horny parts such as nails or scales or hoofs
 
extensor
a skeletal muscle whose contraction extends or stretches a body part
 
external body part
any body part visible externally
 
external carotid
the branch of the carotid artery that supplies blood to the face and tongue and external parts of the head
 
external ear
the part of the ear visible externally
 
external gill
occurs in some mollusks and in tadpoles and other immature amphibians
 
external iliac artery
the outer branch of the common iliac artery on either side of the body; becomes the femoral artery
 
external iliac vein
a continuation of the femoral vein; unites with the internal iliac vein to form the common iliac vein
 
external jugular vein
formed by the junction of the posterior auricular and the retromandibular veins; empties into the subclavian vein
 
external nasal vein
one of the veins that drain the external nose and empty into the angular or facial vein
 
external organ
an organ that is situated on or near the surface of the body
 
external orifice
the orifice through which urine is discharged
 
exteroceptor
any receptor that responds to stimuli outside the body
 
extremity
that part of a limb that is farthest from the torso
 
eye muscle
one of the small muscles of the eye that serve to rotate the eyeball
 
eye
the organ of sight
 
eyeball
the ball-shaped capsule containing the vertebrate eye
 
eyecup
(embryology) a two-walled cuplike depression that develops into the pigmented and sensory layers of the retina
 
eyelid
either of two folds of skin that can be moved to cover or open the eye
 
face
the part of an animal corresponding to the human face
 
face
the front of the human head from the forehead to the chin and ear to ear
 
facia
a sheet or band of fibrous connective tissue separating or binding together muscles and organs etc
 
facial muscle
any of the skeletal muscles of the face
 
facial vein
any of several veins draining the face
 
facial
cranial nerve that supplies facial muscles
 
falciform ligament
a ligament that attaches part of the liver to the diaphragm and the abdominal wall
 
fallen arch
an instep flattened so the entire sole rests on the ground
 
Fallopian tube
either of a pair of tubes conducting the egg from the ovary to the uterus
 
false glottis
the opening between the false vocal folds
 
false vocal cord
either of the upper two vocal cords that are not involved in vocalization
 
family jewels
external male sex organs
 
fang
hollow or grooved tooth of a venomous snake; used to inject its poison
 
fang
canine tooth of a carnivorous animal; used to seize and tear its prey
 
fang
an appendage of insects that is capable of injecting venom; usually evolved from the legs
 
fanny
external female sex organs
 
fascicle
a bundle of fibers (especially nerve fibers)
 
fauces
the passage between the back of the mouth and the pharynx
 
faucial tonsil
either of two masses of lymphatic tissue one on each side of the oral pharynx
 
feature
the characteristic parts of a person's face: eyes and nose and mouth and chin
 
female internal reproductive organ
the reproductive organs of a woman
 
female reproductive system
the reproductive system of females
 
femoral biceps
the biceps muscle of the thigh; it flexes the knee and rotates the leg laterally
 
femoral vein
a vein that accompanies the femoral artery in the same sheath; a continuation of the popliteal vein; becomes the external iliac vein
 
femoris
the longest and thickest bone of the human skeleton; extends from the pelvis to the knee
 
fenestra
a small opening covered with membrane (especially one in the bone between the middle and inner ear)
 
fenestra cochleae
fenestra leading into the cochlea
 
fenestra of the vestibule
fenestra that has the base of the stapes attached to it
 
fertilization membrane
the membrane that forms around a fertilized ovum and prevents penetration by additional spermatozoon
 
fetal circulation
the system of blood vessels and structures through which blood moves in a fetus
 
fetal membrane
any membrane that functions for the protection or nourishment or respiration or excretion of a developing fetus
 
fetlock
projection behind and above a horse's hoof
 
fetlock
the joint between the cannon bone and the pastern
 
fetter bone
the part between the fetlock and the hoof
 
fibrocartilage
cartilage that is largely composed of fibers like those in ordinary connective tissue
 
fibrous joint
an immovable joint (especially between the bones of the skull)
 
fibrous tissue
tissue consisting of or containing fibers in both animals and plants
 
fibular vein
accompany the peroneal arteries; arising in the heel and running up the back of the leg to join the posterior tibial veins of the popliteal vein
 
fifth cranial nerve
the main sensory nerve of the face and motor nerve for the muscles of mastication
 
filament
a threadlike structure (as a chainlike series of cells)
 
fillet
a bundle of sensory nerve fibers going to the thalamus
 
fimbria
thin projections forming a fringe (especially around the ovarian end of the Fallopian tube)
 
fin
organ of locomotion and balance in fishes and some other aquatic animals
 
finger
any of the terminal members of the hand (sometimes excepting the thumb)
 
fingernail
the nail at the end of a finger
 
first cranial nerve
a collective term for numerous olfactory filaments in the nasal mucosa
 
first stomach
the first compartment of the stomach of a ruminant; here food is collected and returned to the mouth as cud for chewing
 
fishbone
a bone of a fish
 
fissure
(anatomy) a long narrow slit or groove that divides an organ into lobes
 
fissure of Rolando
a brain fissure extending upward on the lateral surface of both hemispheres; separates the frontal and parietal lobes
 
fissure of Sylvius
the deepest and most prominent of the cortical fissures; separates the frontal lobes and temporal lobes in both hemispheres
 
fistula
an abnormal passage leading from a suppurating cavity to the body surface
 
flab
loose or flaccid body fat
 
flag
a conspicuously marked or shaped tail
 
flagellum
a lash-like appendage used for locomotion (e.g., in sperm cells and some bacteria and protozoa)
 
flame cell
organ of excretion in flatworms
 
flank
the side between ribs and hipbone
 
flap
a movable piece of tissue partly connected to the body
 
flatfoot
a foot afflicted with a fallen arch; abnormally flattened and spread out
 
flesh
the soft tissue of the body of a vertebrate: mainly muscle tissue and fat
 
flexor
a skeletal muscle whose contraction bends a joint
 
flipper
the flat broad limb of aquatic animals specialized for swimming
 
fluke
either of the two lobes of the tail of a cetacean
 
fold
a folded part (as in skin or muscle)
 
follicle
any small spherical group of cells containing a cavity
 
fontanel
any membranous gap between the bones of the cranium in an infant or fetus
 
foot
the part of the leg of a human being below the ankle joint
 
foot
any of various organs of locomotion or attachment in invertebrates
 
fore wing
either of the anterior pair of wings on an insect that has four wings
 
forearm
the part of the superior limb between the elbow and the wrist
 
forebrain
the anterior portion of the brain; the part of the brain that develops from the anterior part of the neural tube
 
forefinger
the finger next to the thumb
 
forefoot
a front foot of a quadruped
 
forehead
the large cranial bone forming the front part of the cranium: includes the upper part of the orbits
 
foreleg
the forelimb of a quadruped
 
forelimb
the front limb (or the homologous structure in other animals, such as a flipper or wing)
 
forepaw
front paw; analogous to the human hand
 
foreskin
a fold of skin covering the tip of the penis
 
foreskin
a fold of skin covering the tip of the clitoris
 
fornix
generally any arch shaped structure (but often it refers to the arched roof of an anatomical space)
 
fornix
an arched bundle of white fibers at the base of the brain by which the hippocampus of each hemisphere projects to the contralateral hippocampus and to the thalamus and mamillary bodies
 
fossa
a concavity in a surface (especially an anatomical depression)
 
fossorial foot
foot adapted for digging as in moles
 
fourth cranial nerve
either of the two cranial nerves on either side that control the superior oblique muscles of the eyes
 
fourth ventricle
an irregular ventricle between the third ventricle and the central canal of the spinal cord
 
fovea
area consisting of a small depression in the retina containing cones and where vision is most acute
 
frame
the hard structure (bones and cartilages) that provides a frame for the body of an animal
 
frill
(paleontology) a bony plate that curves upward behind the skull of many ceratopsian dinosaurs
 
frill
an external body part consisting of feathers or hair about the neck of a bird or other animal
 
frontal cortex
that part of the cerebral cortex in either hemisphere of the brain lying directly behind the forehead
 
frontal gyrus
any of the convolutions of the outer surface of the frontal lobe of the cerebrum
 
frontal sinus
one of a pair of cavities in the frontal bone
 
frontal suture
the suture between two halves of the frontal bone (usually obliterated by the age of 6)
 
fundus
(anatomy) the base of a hollow organ or that part of the organ farthest from its opening
 
funiculus
any of several body structure resembling a cord
 
furcula
a forked bone formed by the fusion of the clavicles of most birds
 
fuzz
filamentous hairlike growth on a plant
 
gall bladder
a muscular sac attached to the liver that stores bile (secreted by the liver) until it is needed for digestion
 
ganglion
an encapsulated neural structure consisting of a collection of cell bodies or neurons
 
gaskin
lower part of a horse's thigh between the hock and the stifle
 
gastric mill
thick-walled muscular pouch below the crop in many birds and reptiles for grinding food
 
gastric vein
one of several veins draining the stomach walls
 
gastrocnemius
the muscle in the back part of the leg that forms the greater part of the calf; responsible for the plantar flexion of the foot
 
gastroepiploic vein
one of two veins serving the great curvature of the stomach
 
genicular vein
veins that drain blood from structures around the knee; empty into the popliteal vein
 
geniculate body
one of four small oval masses that protrude slightly from the underside of the thalamus and function as synaptic centers on the way to the cerebral cortex
 
genital system
organs and tissues involved in the production and maturation of gametes and in their union and subsequent development as offspring
 
germ
a small apparently simple structure (as a fertilized egg) from which new tissue can develop into a complete organism
 
germ layer
(embryology) any of the 3 layers of cells differentiated in embryos following gastrulation
 
GI tract
tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination
 
gingiva
the tissue (covered by mucous membrane) of the jaws that surrounds the bases of the teeth
 
ginglymoid joint
a freely moving joint in which the bones are so articulated as to allow extensive movement in one plane
 
girdle
an encircling or ringlike structure
 
glabella
a smooth prominence of the frontal bone between and above the eyebrows; the most forward projecting point of the forehead in the midline at the level of the supraorbital ridges
 
gland
any of various organs that synthesize substances needed by the body and release it through ducts or directly into the bloodstream
 
glandulae sebaceae
a cutaneous gland that secretes sebum (usually into a hair follicle) for lubricating hair and skin
 
glans
a small rounded structure; especially that at the end of the penis or clitoris
 
glans clitoridis
small mass of erectile tissue at the end of the body of the clitoris
 
glans penis
the conical mass of erectile tissue that forms the head of the penis
 
glenoid cavity
the concavity in the head of the scapula that receives the head of the humerus to form the shoulder joint
 
glenoid fossa
a deep concavity in the temporal bone at the root of the zygomatic arch that receives the condyle of the mandible
 
glia
sustentacular tissue that surrounds and supports neurons in the central nervous system; glial and neural cells together compose the tissue of the central nervous system
 
globus pallidus
the inner pale yellow part of the lenticular nucleus
 
glochid
a barbed spine or bristle (often tufted on cacti)
 
glomerulus
a small intertwined group of capillaries in the malpighian body; it filters the blood during urine formation
 
glossopharyngeal nerve
sensory nerve to the pharynx and back of the tongue; motor fibers innervate muscles that elevate the pharynx and larynx; includes parasympathetic fibers to the otic ganglion
 
glottis
the vocal apparatus of the larynx; the true vocal folds and the space between them where the voice tone is generated
 
glottis vera
the space between the two true vocal folds
 
glute
any one of three large skeletal muscles that form the buttock and move the thigh
 
gluteal vein
veins draining the gluteal muscles on either side of the body
 
gluteus maximus
the outermost of the three gluteal muscles
 
gluteus medius
the middle of the three gluteal muscles
 
gluteus minimus
the innermost of the three gluteal muscles
 
gnathion
the most inferior point of the mandible in the midline
 
Golgi apparatus
a netlike structure in the cytoplasm of animal cells (especially in those cells that produce secretions)
 
gonad
a gland in which gametes (sex cells) are produced
 
gonion
the craniometric point on either side at the apex of the lower jaw
 
Graafian follicle
a vascular body in a mammalian ovary enclosing a developing egg
 
graft
(surgery) tissue or organ transplanted from a donor to a recipient; in some cases the patient can be both donor and recipient
 
granulation
new connective tissue and tiny blood vessels that form on the surfaces of a wound during the healing process
 
gray matter
greyish nervous tissue containing cell bodies as well as fibers; forms the cerebral cortex consisting of unmyelinated neurons
 
great adductor muscle
the muscle that adducts and extends the thigh
 
great cerebral vein
a cerebral vein formed by the two internal cerebral veins and continuing into the sinus rectus
 
great saphenous vein
the longest vein in the body; runs from foot to the groin where it joins the femoral vein
 
greater pectoral muscle
a skeletal muscle that adducts and rotates the arm
 
greater peritoneal sac
the interior of the peritoneum; a potential space between layers of the peritoneum
 
greater rhomboid muscle
rhomboid muscle that draws the scapula toward the spinal column
 
green gland
one of a pair of glands (believed to have excretory functions) in some crustaceans near the base of the large antennae
 
grinder
grinding tooth with a broad crown; located behind the premolars
 
groin
the crease at the junction of the inner part of the thigh with the trunk together with the adjacent region and often including the external genitals
 
groove
(anatomy) any furrow or channel on a bodily structure or part
 
gustatory organ
an oval sensory end organ on the surface of the tongue
 
haemal arch
a structure arising ventrally from a vertebral centrum and enclosing the caudal blood vessels
 
hair
a filamentous projection or process on an organism
 
hair follicle
a small tubular cavity containing the root of a hair; small muscles and sebaceous glands are associated with them
 
hair
any of the cylindrical filaments characteristically growing from the epidermis of a mammal
 
half-moon
the crescent-shaped area at the base of the human fingernail
 
hamate
the wrist bone in line with the 4th and 5th fingers
 
hammer
the ossicle attached to the eardrum
 
hammertoe
a deformed toe which is bent in a clawlike arch
 
hamstring
one of the tendons at the back of the knee
 
hand
terminal part of the forelimb in certain vertebrates (e.g. apes or kangaroos)
 
hand
the (prehensile) extremity of the superior limb
 
haunch
the hip and buttock and upper thigh in human beings
 
haunch
the loin and leg of a quadruped
 
haustorium
a root-like attachment in parasitic plants that penetrates and obtains food from the host
 
Haversian canal
any of the many tiny canals that contain blood vessels and connective tissue and that form a network in bone
 
haw
the nictitating membrane of a horse
 
hawk nose
a nose curved downward like the beak of a hawk
 
head
the rounded end of a bone that fits into a rounded cavity in another bone to form a joint
 
head
that part of a skeletal muscle that is away from the bone that it moves
 
heart ventricle
a chamber of the heart that receives blood from an atrium and pumps it to the arteries
 
heart
the hollow muscular organ located behind the sternum and between the lungs; its rhythmic contractions move the blood through the body
 
heel
the back part of the human foot
 
hemizygos vein
a continuation of the left ascending lumbar vein; crosses the midline at the 8th vertebra and empties into the azygos vein
 
hemorrhoidal vein
any of several veins draining the walls of the anal canal and rectum
 
hepatic duct
the duct that drains bile from the liver
 
hepatic lobe
any of the five lobes forming the liver
 
hepatic portal vein
a short vein that carries blood into the liver
 
hepatic vein
a vein that drains the liver; empties into the vena cava
 
heterocercal fin
a tail fin with unequal lobes in which the vertebral column turns upward into the larger lobe as in sharks
 
heterodactyl foot
a bird's foot having the first and second toes of each foot directed backward and the third and fourth forward
 
heterograft
tissue from an animal of one species used as a temporary graft (as in cases of severe burns) on an individual of another species
 
hilum
(anatomy) a depression or fissure where vessels or nerves or ducts enter a bodily organ
 
hind leg
the back limb of a quadruped
 
hind limb
a posterior appendage such as a leg or the homologous structure in other animals
 
hindbrain
the posterior portion of the brain including cerebellum and brainstem
 
hindfoot
a rear foot of a quadruped
 
hindgut
the caudal part of the alimentary canal in vertebrate embryos
 
hip
either side of the body below the waist and above the thigh
 
hip socket
the socket part of the ball-and-socket joint between the head of the femur and the innominate bone
 
hip
the structure of the vertebrate skeleton supporting the lower limbs in humans and the hind limbs or corresponding parts in other vertebrates
 
hipbone
large flaring bone forming one half of the pelvis; made up of the ilium and ischium and pubis
 
hippocampus
a complex neural structure (shaped like a sea horse) consisting of grey matter and located on the floor of each lateral ventricle; intimately involved in motivation and emotion as part of the limbic system; has a central role in the formation of memories
 
hock
tarsal joint of the hind leg of hoofed mammals; corresponds to the human ankle
 
homocercal fin
symmetrical tail fin extending beyond the end of the vertebral column as in most bony fishes
 
hood
(zoology) an expandable part or marking that resembles a hood on the head or neck of an animal
 
hoof
the foot of an ungulate mammal
 
hoof
the horny covering of the end of the foot in ungulate mammals
 
hooks
large strong hand (as of a fighter)
 
horn
any hard protuberance from the head of an organism that is similar to or suggestive of a horn
 
horn
one of the bony outgrowths on the heads of certain ungulates
 
horny structure
any rigid body structure composed primarily of keratin
 
horse's foot
the hoof of a horse
 
horseback
the back of a horse
 
human head
the head of a human being
 
humerus
bone extending from the shoulder to the elbow
 
hyaline cartilage
translucent cartilage that is common in joints and the respiratory passages; forms most of the fetal skeleton
 
hyaloid
the transparent membrane enveloping the vitreous humor of the eye and separating it from the retina
 
hymen
a fold of tissue that partly covers the entrance to the vagina of a virgin
 
hyoid
a U-shaped bone at the base of the tongue that supports the tongue muscles
 
hypochondrium
the upper region of the abdomen just below the lowest ribs on either side of the epigastrium
 
hypodermis
layer of cells that secretes the chitinous cuticle in e.g. arthropods
 
hypogastric artery
the inner branch of the common iliac artery on either side of the body; divides into several branches that supply blood to the pelvic and gluteal areas
 
hypogastric plexus
a plexus of nerves serving the pelvic viscera
 
hypogastric vein
a vein that unites with the external iliac vein to form the common iliac vein
 
hypoglossal
supplies intrinsic muscles of the tongue and other tongue muscles
 
hypophyseal stalk
the funnel-shaped stalk connecting the pituitary gland to the hypothalamus
 
hypophysis
the master gland of the endocrine system; located at the base of the brain
 
hypothalamus
a basal part of the diencephalon governing autonomic nervous system
 
ileocecal valve
valve between the ileum of the small intestine and the cecum of the large intestine; prevents material from flowing back from the large to the small intestine
 
ileocolic vein
a vein that drains the end of the ileum and the appendix and the cecum and the lower part of the ascending colon
 
ileum
the part of the small intestine between the jejunum and the cecum
 
iliac vein
one of three veins draining the pelvic area
 
iliolumbar vein
a branch of the internal iliac vein
 
ilium
the upper and widest of the three bones making up the hipbone
 
immune system
a system (including the thymus and bone marrow and lymphoid tissues) that protects the body from foreign substances and pathogenic organisms by producing the immune response
 
imperforate anus
a congenital defect of the anus; there is partial or complete obstruction of the anal opening
 
imperforate hymen
hymen that is completely closed so that menstrual blood cannot flow out
 
incisor
a tooth for cutting or gnawing; located in the front of the mouth in both jaws
 
incompetent cervix
(obstetrics) uterine cervix that becomes dilated before term and without labor often resulting in miscarriage or premature birth
 
inferior cerebellar artery
the inferior branch of the cerebellar artery
 
inferior cerebral vein
veins that drain the undersurface of the cerebral hemispheres and empty into the cavernous and transverse sinuses
 
inferior colliculus
an essential auditory center in the midbrain
 
inferior epigastric vein
empties into the external iliac vein
 
inferior labial vein
a tributary of the facial vein that drains the lower lip
 
inferior mesenteric artery
arises near the lower end of the aorta and supplies the large intestine
 
inferior ophthalmic vein
a vein that drains a venous network in the floor and medial wall of the eye socket
 
inferior pulmonary vein
either of two pulmonary veins (left and right) returning blood from the inferior lobes of the lungs
 
inferior rectus
the ocular muscle whose contraction turns the eyeball down and medially
 
inferior thalamostriate vein
tributaries to the basal vein
 
inferior thyroid vein
any of several veins on each side that drain the thyroid gland and empty into the innominate vein
 
inferior vena cava
receives blood from lower limbs and abdominal organs and empties into the posterior part of the right atrium of the heart; formed from the union of the two iliac veins
 
inferior vocal cord
either of the two lower vocal folds that come together to form the glottis; produce a vocal tone when they are approximated and air from the lungs passes between them
 
infundibulum
any of various funnel-shaped parts of the body (but especially the hypophyseal stalk)
 
ingrown hair
a hair that does not emerge from the follicle but remains embedded in the skin (usually causing inflammation)
 
ingrown toenail
toenail having its free tip or edges embedded in the surrounding flesh
 
inion
the craniometric point that is the most prominent point at the back of the head (at the occipital protuberance)
 
inner ear
a complex system of interconnecting cavities; concerned with hearing and equilibrium
 
innominate artery
a large artery arising from the arch of the aorta and divides into the right subclavian artery and the right common carotid artery; supplies the right side of the neck and head and the right shoulder and arm
 
instep
the arch of the foot
 
integumentary system
the skin and its appendages
 
intercapitular vein
veins connecting the dorsal and palmar veins of the hand or the dorsal and plantar veins of the foot
 
intercostal vein
several veins draining the intercostal spaces of the rib cage
 
intercostal
muscles between the ribs; they contract during inspiration
 
intermaxillary suture
the suture between the two maxillae of the upper jawbone
 
internal auditory vein
veins that drain the inner ear
 
internal carotid artery
the branch of the carotid artery that supplies blood to the brain and eyes and internal parts of the head
 
internal cerebral vein
two paired veins passing caudally near the midline and uniting to form the great cerebral vein
 
internal jugular vein
a continuation of the sigmoid sinus of the dura mater; joins the subclavian vein to form the brachiocephalic vein
 
internal maxillary artery
the maxillary artery that supplies deep structure of the face and some of the meninges
 
internal organ
a main organ that is situated inside the body
 
internasal suture
the suture between the two nasal bones
 
interparietal suture
the suture uniting the two parietal bones
 
interphalangeal joint
any of the joints between the phalanges of the fingers or toes
 
interstice
a small structural space between tissues or parts of an organ
 
interstitial tissue
tissue between the cells of a structure or part in plant or animal
 
intervertebral vein
one of several veins accompanying spinal nerves
 
intestinal artery
an artery that is a branch of the superior mesenteric artery that supplies the jejunum
 
intima
the innermost membrane of an organ (especially the inner lining of an artery or vein or lymphatic vessel)
 
introitus
entrance or opening to a hollow organ or tube (especially the vaginal opening)
 
investment
outer layer or covering of an organ or part or organism
 
involuntary muscle
a muscle that contracts without conscious control and found in walls of internal organs such as stomach and intestine and bladder and blood vessels (excluding the heart)
 
iris
muscular diaphragm that controls the size of the pupil which in turn controls the amount of light that enters the eye; it forms the colored portion of the eye
 
ischial bone
one of the three sections of the hipbone; situated below the ilium
 
islands of Langerhans
cell clusters in the pancreas that form the endocrine part of that organ; secrete insulin and other hormones
 
jaw
the part of the skull of a vertebrate that frames the mouth and holds the teeth
 
jaw
the bones of the skull that frame the mouth and serve to open it; the bones that hold the teeth
 
jawbone
the jaw in vertebrates that is hinged to open the mouth
 
jejunum
the part of the small intestine between the duodenum and the ileum
 
jowl
a fullness and looseness of the flesh of the lower cheek and jaw (characteristic of aging)
 
jugal point
the craniometric point at the union of the frontal and temporal processes of the zygomatic bone
 
jugular
veins in the neck that return blood from the head
 
keel
the median ridge on the breastbone of birds that fly
 
kidney
either of two bean-shaped excretory organs that filter wastes (especially urea) from the blood and excrete them and water in urine
 
knee
joint between the femur and tibia in a quadruped; corresponds to the human knee
 
kneecap
a small flat triangular bone in front of the knee that protects the knee joint
 
knuckle
a joint of a finger when the fist is closed
 
labia majora
the two outer folds of the vulva
 
labia minora
the two inner folds of the vulva
 
labial vein
a vein draining the lips of the mouth
 
labial vein
veins draining the lips of the vulva
 
labium
a liplike structure that bounds a bodily orifice (especially any of the four labiate folds of a woman's vulva)
 
lachrymal duct
any of several small ducts that carry tears from the lacrimal glands
 
lachrymal gland
any of the glands in the eyes that secrete tears
 
lacrimal apparatus
the structures that secrete and drain tears from the eye
 
lacrimal bone
small fragile bone making up part of the front inner walls of each eye socket and providing room for the passage of the lacrimal ducts
 
lacrimal vein
drains the lacrimal gland; empties into the superior ophthalmic vein
 
lacteal
any of the lymphatic vessels that convey chyle from the small intestine to the thoracic duct
 
lactiferous duct
ducts of the mammary gland that carry milk to the nipple
 
lambda
the craniometric point at the junction of the sagittal and lamboid sutures of the skull
 
lamboid suture
the suture between the occipital and parietal bones
 
lamella
a thin membrane that is one of the calcified layers that form bones
 
lamina
a thin plate or layer (especially of bone or mineral)
 
lamina arcus vertebrae
lamina of the vertebral arch; the flattened posterior part of the vertebral arch from which the spinous process extends
 
landmark
an anatomical structure used as a point of origin in locating other anatomical structures (as in surgery) or as point from which measurements can be taken
 
language area
a large cortical area (in the left hemisphere in most people) containing all the centers associated with language
 
lantern jaw
a long thin lower jaw
 
lap
the upper side of the thighs of a seated person
 
lappet
a fleshy wrinkled and often brightly colored fold of skin hanging from the neck or throat of certain birds (chickens and turkeys) or lizards
 
large intestine
beginning with the cecum and ending with the rectum; includes the cecum and the colon and the rectum; extracts moisture from food residues which are later excreted as feces
 
laryngeal vein
one of two veins draining the larynx
 
laryngopharynx
the lower part of the pharynx
 
larynx
a cartilaginous structure at the top of the trachea; contains elastic vocal cords that are the source of the vocal tone in speech
 
lat
a broad flat muscle on either side of the back
 
lateral condyle
a condyle on the outer side of the lower extremity of the femur
 
lateral epicondyle
epicondyle near the lateral condyle of the femur
 
lateral line
sense organs of fish and amphibians; believed to detect pressure changes in the water
 
lateral ventricle
either of two horseshoe-shaped ventricles one in each cerebral hemisphere; they communicate with the third ventricle via the foramen of Monro
 
layer
thin structure composed of a single thickness of cells
 
leaf node
(botany) the small swelling that is the part of a plant stem from which one or more leaves emerge
 
left brain
the cerebral hemisphere to the left of the corpus callosum that controls the right half of the body
 
left coronary artery
arises from the left aortic sinus; supplies the left side of the heart
 
left gastric vein
arises from a union of veins from the gastric cardia; runs in the lesser omentum; empties into the portal vein
 
left ventricle
the chamber on the left side of the heart that receives arterial blood from the left atrium and pumps it into the aorta
 
left
the hand that is on the left side of the body
 
leg
a human limb; commonly used to refer to a whole limb but technically only the part of the limb between the knee and ankle
 
leg
a structure in animals that is similar to a human leg and used for locomotion
 
leg bone
a bone of the leg
 
lens capsule
a tenuous mesoblastic membrane surrounding the lens of the eye
 
lens nucleus
the central structure of the lens that is surrounded by the cortex
 
lenticular nucleus
a basal ganglion shaped like a lens and including the outer reddish putamen and the inner pale yellow pallidum
 
leptomeninges
the two innermost layers of the meninges; cerebrospinal fluid circulates between these innermost layers
 
lesser omentum
a part of the peritoneum attached to the stomach and liver and supporting the hepatic vessels
 
lesser rhomboid muscle
rhomboid muscle that draws the scapula toward the vertebral column and slightly upward
 
levator
a muscle that serves to lift some body part (as the eyelid or lip)
 
lien
a large dark-red oval organ on the left side of the body between the stomach and the diaphragm; produces cells involved in immune responses
 
ligament
a sheet or band of tough fibrous tissue connecting bones or cartilages or supporting muscles or organs
 
ligamentum teres uteri
ligament attached to the uterus on either side in front of and below the opening of the Fallopian tube and passing through the inguinal canal to the labia majora
 
limb
one of the jointed appendages of an animal used for locomotion or grasping: arm; leg; wing; flipper
 
limbic brain
a system of functionally related neural structures in the brain that are involved in emotional behavior
 
limbus
a border or edge of any of various body parts distinguished by color or structure
 
lingual vein
a vein that receives blood from the tongue and the floor of the mouth and empties into the internal jugular or the facial vein
 
lip
either of two fleshy folds of tissue that surround the mouth and play a role in speaking
 
liposome
an artificially made microscopic vesicle into which nucleic acids can be packaged; used in molecular biology as a transducing vector
 
little finger
the finger farthest from the thumb
 
little toe
the fifth smallest outermost toe
 
liver
large and complicated reddish-brown glandular organ located in the upper right portion of the abdominal cavity; secretes bile and functions in metabolism of protein and carbohydrate and fat; synthesizes substances involved in the clotting of the blood; synthesizes vitamin A; detoxifies poisonous substances and breaks down worn-out erythrocytes
 
lobate foot
a bird's foot having separate toes each with membranous flaps along the sides
 
lobe
(anatomy) a somewhat rounded subdivision of a bodily organ or part
 
lobe of the lung
any of the three lobes of the right lung or the two lobes of the left lung
 
lobule
a small lobe or subdivision of a lobe
 
locule
a small cavity or space within an organ or in a plant or animal
 
locus niger
a layer of deeply pigmented grey matter in the midbrain; associated with the striate body; is involved in metabolic disturbances associated with Parkinson's disease and with Huntington's disease
 
loin
either side of the backbone between the hipbone and the ribs in humans as well as quadrupeds
 
loins
the region of the hips and groin and lower abdomen
 
loins
the lower part of the abdomen just above the external genital organs
 
long bone
in limbs of vertebrate animals: a long cylindrical bone that contains marrow
 
love handle
excess fat around the waistline
 
lower respiratory tract
the bronchi and lungs
 
lumbar nerve
any of five pairs of spinal nerves emerging from the lumbar section of the spinal cord
 
lumbar plexus
a plexus of nerves formed by the ventral branches of the first four lumbar nerves
 
lumbar plexus
a lymphatic plexus located along the lower portion of the aorta and iliac vessels
 
lumbar vein
veins that drain the posterior body wall and the lumbar vertebral venous plexuses
 
lumbar vertebra
one of 5 vertebrae in the human vertebral column; lumbar vertebrae extend from the twelfth thoracic vertebra down to the sacral vertebrae
 
lumbosacral plexus
a nerve plexus formed by the ventral divisions of the coccygeal and sacral and lumbar nerves; supplies the lower limbs and perineum and coccygeal area
 
lumen
a cavity or passage in a tubular organ
 
lunate bone
one of the eight small wrist bones
 
lung
either of two saclike respiratory organs in the chest of vertebrates; serves to remove carbon dioxide and provide oxygen to the blood
 
Luschka's tonsil
a collection of lymphatic tissue in the throat behind the uvula (on the posterior wall and roof of the nasopharynx)
 
lymph gland
the source of lymph and lymphocytes
 
lymph vessel
a vascular duct that carries lymph which is eventually added to the venous blood circulation
 
lymphatic system
the interconnected system of spaces and vessels between body tissues and organs by which lymph circulates throughout the body
 
lymphatic tissue
tissue making up the lymphatic system
 
lysosome
an organelle found in the cytoplasm of most cells (especially in leukocytes and liver and kidney cells)
 
macula
a small yellowish central area of the retina that is rich in cones and that mediates clear detailed vision
 
male chest
the chest of a man
 
male internal reproductive organ
the reproductive organs of a man
 
male reproductive gland
the reproductive organs of a man
 
male reproductive system
the reproductive system of males
 
malpighian body
the capsule that contains Bowman's capsule and a glomerulus at the expanded end of a nephron
 
malposed tooth
a tooth that has grown in a faulty position
 
mamilla
the small projection of a mammary gland
 
mamma
milk-secreting organ of female mammals
 
mandibular gland
a salivary gland inside the lower jaw on either side that produces most of the nocturnal saliva; discharges saliva into the mouth under the tongue
 
manubrium
the upper part of the breastbone
 
marrowbone
a bone containing edible marrow; used especially in flavoring soup
 
marsupium
an external abdominal pouch in most marsupials where newborn offspring are suckled
 
masseter
a large muscle that raises the lower jaw and is used in chewing
 
mastoid
process of the temporal bone behind the ear at the base of the skull
 
mastoidale
the craniometric point at the lowest point of the mastoid process
 
matrix
the formative tissue at the base of a nail
 
maxilla
the jaw in vertebrates that is fused to the cranium
 
maxillary sinus
one of a pair of sinuses forming a cavity in the maxilla
 
maxillary vein
posterior continuation of the pterygoid plexus; joins the superficial temporal vein to form the retromandibular vein
 
meatus
a natural body passageway
 
medial condyle
a condyle on the inner side of the lower extremity of the femur
 
medial rectus
the ocular muscle whose contraction turns the eyeball medially
 
mediastinum
the part of the thoracic cavity between the lungs that contains the heart and aorta and esophagus and trachea and thymus
 
medulla
the inner part of an organ or structure in plant or animal
 
medulla spinalis
a major part of the central nervous system which conducts sensory and motor nerve impulses to and from the brain; a long tubelike structure extending from the base of the brain through the vertebral canal to the upper lumbar region
 
megacolon
an abnormal enlargement of the colon; can be congenital (as in Hirschsprung's disease) or acquired (as when children refuse to defecate)
 
Meibomian gland
a long sebaceous gland that lubricates the eyelids
 
member
the male sex organ (`member' is a euphemism)
 
membrane bone
any bone that develops within membranous tissue without previous cartilage formation; e.g. the clavicle and bones of the skull
 
membrane
a pliable sheet of tissue that covers or lines or connects the organs or cells of animals or plants
 
membranous labyrinth
the sensory structures of the inner ear including the labyrinthine receptors and the cochlea; contained within the bony labyrinth
 
meningeal veins
veins at accompany the meningeal arteries
 
meninges
a membrane (one of 3) that envelops the brain and spinal cord
 
meniscus
(anatomy) a disk of cartilage that serves as a cushion between the ends of bones that meet at a joint
 
mentum
a projection below the mouth of certain mollusks that resembles a chin
 
mesencephalon
the middle portion of the brain
 
mesenchyme
mesodermal tissue that forms connective tissue and blood and smooth muscles
 
mesenteric plexus
a plexus of autonomic nerves
 
mesenteric vein
a tributary of the portal vein passing from the intestine between the two layers of mesentery
 
mesentery
a double layer of peritoneum that attaches to the back wall of the abdominal cavity and supports the small intestines
 
mesoblast
the middle germ layer that develops into muscle and bone and cartilage and blood and connective tissue
 
mesocolon
mesentery that holds the lower colon to the dorsal abdominal wall
 
mesothelium
epithelium originating in the embryonic mesoderm; lines the primordial body cavity
 
metacarpal vein
dorsal and palmar veins of the hand
 
metacarpal
any bone of the hand between the wrist and fingers
 
metacarpus
the part of the hand between the carpus and phalanges
 
metaphysis
the growing part of a long bone between the diaphysis and the epiphysis
 
metatarsal
any bone of the foot between the ankle and the toes
 
metatarsal arch
the short lateral arch formed by the heads of the metatarsals
 
metatarsal vein
dorsal and plantar branches of veins serving the metatarsal region of the foot
 
metatarsus
the skeleton of the human foot between the toes and the tarsus; the corresponding part of the foot in birds or of the hind foot in quadrupeds
 
metencephalon
the part of the hindbrain that develops into the pons and the cerebellum
 
metopion
the craniometric point midway between the frontal eminences of the skull
 
microglia
neuroglial tissue of mesodermal origin that can become phagocytic
 
micropenis
an abnormally small penis
 
microtubule
a microscopically small tubule
 
mid-calf
the middle of the calf; half way between the knee and ankle
 
middle cerebral artery
one of two branches of the internal carotid artery; divides into three branches
 
middle cerebral vein
either of two cerebral veins
 
middle ear
the main cavity of the ear; between the eardrum and the inner ear
 
middle finger
the second finger; between the index finger and the ring finger
 
middle meningeal artery
branch of the maxillary artery; its branches supply meninges
 
middle temporal vein
arises near the eye; joins the superficial temporal veins to form the retromandibular vein
 
middle thyroid vein
a vein on each side that drains the lateral part of the thyroid and empties into the internal jugular vein
 
middle
the middle area of the human torso (usually in front)
 
minge
vulgar term for a woman's pubic hair or genitals
 
minimus
the fifth digit; the little finger or little toe
 
modiolus
the central conical bony pillar of the cochlea
 
mons
a mound of fatty tissue covering the pubic area in women
 
Montgomery's tubercle
one of the sebaceous glands on the areolae of the breast that lubricate the breast during breast-feeding
 
mouth
the externally visible part of the oral cavity on the face and the system of organs surrounding the opening
 
mouth
the opening through which food is taken in and vocalizations emerge
 
mouthpart
any part of the mouth of an insect or other arthropod especially one adapted to a specific way of feeding
 
MPS
a widely distributed system of free and fixed macrophages derived from bone marrow
 
mucosa
mucus-secreting membrane lining all body cavities or passages that communicate with the exterior
 
muscle system
the muscular system of an organism
 
muscle
animal tissue consisting predominantly of contractile cells
 
muscle
one of the contractile organs of the body
 
musculophrenic vein
veins that drain the upper abdominal wall and the lower intercostal spaces and the abdomen
 
musculoskeletal system
the system of muscles and tendons and ligaments and bones and joints and associated tissues that move the body and maintain its form
 
musculospiral nerve
largest branch of the brachial plexus; extends down the humerus to the lateral epicondyle where it divides into one branch that goes to the skin on the back of the hand and another that goes to the underlying extensor muscles
 
musculus abductor digiti minimi manus
the abductor muscle of the little finger
 
musculus abductor digiti minimi pedis
the abductor muscles of the little toe
 
musculus abductor hallucis
the abductor muscle of the great toe
 
musculus abductor pollicis
the abductor muscle of the thumb
 
musculus adductor brevis
the short adductor muscle of the thigh
 
musculus adductor hallucis
the adductor muscle of the great toe
 
musculus adductor longus
the long adductor muscle of the thigh
 
musculus articularis cubiti
a small branch of the triceps that inserts into the capsule of the elbow joint
 
musculus articularis genus
the articular muscle of the knee
 
musculus pectoralis minor
a skeletal muscle that draws down the scapula or raises the ribs
 
musculus pectoralis
either of two large muscles of the chest
 
musculus quadriceps femoris
a muscle of the thigh that extends the leg
 
musculus sartorius
a muscle in the thigh that helps to rotate the leg into the sitting position assumed by a tailor; the longest muscle in the human body
 
musculus scalenus
any of four pairs of muscles extending from the cervical vertebrae to the second rib; involved in moving the neck and in breathing
 
musculus serratus posterior
skeletal muscle that draws the rib cage backward and downward
 
musculus sphincter ani externus
an external ring of striated muscle surrounding the anus
 
musculus sphincter ani internus
an internal ring of smooth muscle formed by circular fibers of the rectum
 
musculus sphincter ductus choledochi
the smooth muscle sphincter of the common bile duct
 
musculus sphincter ductus pancreatici
the smooth muscle sphincter of the main pancreatic duct
 
musculus sphincter pupillae
a ring of smooth muscle surrounding the iris
 
musculus sphincter pylori
the sphincter muscle of the pylorus that separates the stomach from the duodenum
 
musculus sphincter urethrae
a striated sphincter muscle that constricts the urethra
 
musculus sternocleidomastoideus
one of two thick muscles running from the sternum and clavicle to the mastoid and occipital bone; turns head obliquely to the opposite side; when acting together they flex the neck and extend the head
 
musculus temporalis
muscle extending from the temporal fossa to the coronoid process of the mandible; acts to raise the mandible and close the jaws
 
musculus teres major
teres muscle that moves the arm and rotates it medially
 
musculus teres minor
teres muscle that adducts the arm and rotates it laterally
 
musculus tibialis
either of two skeletal muscle in each leg arising from the tibia; provides for movement of the foot
 
musculus transversalis abdominis
a flat muscle with transverse fibers that forms the anterior and lateral walls of the abdominal cavity
 
musculus triceps brachii
the skeletal muscle having three origins that extends the forearm when it contracts
 
muzzle
forward projecting part of the head of certain animals; includes the jaws and nose
 
myelencephalon
the posterior part of the hindbrain in developing vertebrates; forms the medulla oblongata in adults
 
myenteric plexus
a plexus of unmyelinated fibers and postganglionic autonomic cell bodies in the muscular coat of the esophagus and stomach and intestines
 
myocardium
the middle muscular layer of the heart wall
 
myometrium
the smooth muscle forming the wall of the uterus
 
nabothian gland
one of many small glands of the uterine cervix that secrete mucus
 
nail
horny plate covering and protecting part of the dorsal surface of the digits
 
naked eye
the eye unaided by any optical instrument that alters the power of vision or alters the apparent size or distance of objects
 
naris
any of the openings to the nasal cavities that allow air to flow through the cavities to the pharynx
 
nasal cavity
either of the two cavities lying between the floor of the cranium and the roof of the mouth and extending from the face to the pharynx
 
nasal concha
one of several turbinate bones in the nasal cavity
 
nasal meatus
the passages in the nasal cavity formed by the projections of the nasal conchae
 
nasal septum
a partition of bone and cartilage between the nasal cavities
 
nasal sinus
any of the paired sinuses in the bones of the face adjacent to the nasal cavity that are lined with mucous membrane that is continuous with the lining of the nasal cavities
 
nasal
an elongated rectangular bone that forms the bridge of the nose
 
nasion
the craniometric point at the bridge of the nose where the frontal and nasal bones of the skull meet
 
nasofrontal vein
a vein located in the anterior medial part of the orbit; connects the superior ophthalmic with the angular vein
 
nasolacrimal duct
a duct that carries tears from the lacrimal sac to the nasal cavity
 
nasopharynx
cavity forming the upper part of the pharynx
 
navicular
the largest wrist bone on the thumb side
 
neb
a long projecting or anterior elongation of an animal's head; especially the nose
 
neencephalon
the part of the brain having the most recent phylogenetic origin; the cerebral cortex and related parts
 
neocortex
the cortical part of the neencephalon
 
nephron
any of the small tubules that are the excretory units of the vertebrate kidney
 
nerve pathway
a bundle of myelinated nerve fibers following a path through the brain
 
nerve plexus
a network of intersecting nerves
 
nerve tissue
tissue composed of neurons
 
nerve
any bundle of nerve fibers running to various organs and tissues of the body
 
nervous system
the sensory and control apparatus consisting of a network of nerve cells
 
nervure
one of the horny ribs that stiffen and support the wing of an insect
 
nervus ischiadicus
arises from the sacral plexus and passes about halfway down the thigh where it divides into the common peroneal and tibial nerves
 
nervus oculomotorius
supplies extrinsic muscles of the eye
 
nervus opticus
the cranial nerve that serves the retina
 
nervus phrenicus
one of a pair of nerves that arises from cervical spinal roots and passes down the thorax to innervate the diaphragm and control breathing
 
nervus saphenus
a branch of the femoral nerve that supplies cutaneous branches to the inner aspect of the leg and foot
 
nervus spinalis
any of the 31 pairs of nerves emerging from each side of the spinal cord (each attached to the cord by two roots: ventral and dorsal)
 
nervus vagus
a mixed nerve that supplies the pharynx and larynx and lungs and heart and esophagus and stomach and most of the abdominal viscera
 
neural arch
a structure arising dorsally from a vertebral centrum and enclosing the spinal cord
 
neural structure
a structure that is part of the nervous system
 
neural tube
a tube of ectodermal tissue in the embryo from which the brain and spinal cord develop
 
neuroepithelium
epithelium associated with special sense organs and containing sensory nerve endings
 
neurohypophysis
the posterior lobe of the pituitary body; primarily glandular in nature
 
neuropil
the complex network of unmyelinated axones, dendrites, and glial branches that form the bulk of the central nervous system's grey matter and in which nerve cell bodies are embedded
 
nictitating membrane
a protective fold of skin in the eyes of reptiles and birds and some mammals
 
nodule
small rounded wartlike protuberance on a plant
 
nose
the organ of smell and entrance to the respiratory tract; the prominent part of the face of man or other mammals
 
notochord
a flexible rodlike structure that forms the supporting axis of the body in the lowest chordates and lowest vertebrates and in embryos of higher vertebrates
 
nucleolar organiser
the particular part of a chromosome that is associated with a nucleolus after nuclear division
 
nucleole
a small round body of protein in a cell nucleus; such organelles contain RNA and are involved in protein synthesis
 
nucleus
any histologically identifiable mass of neural cell bodies in the brain or spinal cord
 
obelion
the craniometric point on the sagittal suture near the lamboid suture
 
oblique vein of the left atrium
a tributary of the coronary sinus; on the posterior wall of the left atrium
 
obturator vein
a vein formed by the union of tributaries that drain the hip joints and thigh muscles; empties into the internal iliac vein
 
occipital bone
a saucer-shaped membrane bone that forms the back of the skull
 
occipital cortex
that part of the cerebral cortex in either hemisphere of the brain lying in the back of the head
 
occipital gyrus
any of the convolutions of the outer surface of the occipital lobe of the cerebrum
 
occipital vein
a vein that drains the occipital region
 
occipitomastoid suture
the suture between the occipital and the temporal bones; a continuation of the lamboid suture
 
occiput
back part of the head or skull
 
ocellus
an eye having a single lens
 
OD
the right eye
 
odontoid process
a toothlike process at the back of 2nd vertebra of the neck
 
oil gland
a gland that secretes oil
 
olecranon
process of the ulna that forms the outer bump of the elbow and fits into the fossa of the humerus when the arm is extended
 
olfactory brain
a center in the cerebral hemispheres that governs the sense of smell in lower animals; in humans it seems to mediate complex emotional behavior
 
olfactory bulb
one of two enlargements at the terminus of the olfactory nerve at the base of the brain just above the nasal cavities
 
oligodendria
tissue consisting of glial cells with sheetlike processes that form the myelin sheath of nerve fibers
 
omasum
the third compartment of the stomach of a ruminant
 
omentum
a fold of peritoneum supporting the viscera
 
ommatidium
any of the numerous small cone-shaped eyes that make up the compound eyes of some arthropods
 
opening
an aperture or hole that opens into a bodily cavity
 
operculum
a hard flap serving as a cover for (a) the gill slits in fishes or (b) the opening of the shell in certain gastropods when the body is retracted
 
ophryon
the craniometric point in the midline of the forehead immediately above the orbits
 
ophthalmic vein
either of two veins that serve the eye; empties into the cavernous sinus
 
optic radiation
a nerve pathway from the lateral geniculate body to the visual cortex
 
orbital point
the craniometric point at the lowest point on the lower edge of the orbit
 
organ
a fully differentiated structural and functional unit in an animal that is specialized for some particular function
 
organ of Corti
the hearing organ of the inner ear; contains receptors that respond to sound waves
 
organ of hearing
the part of the ear that is responsible for sensations of sound
 
organ of speech
any of the organs involved in speech production
 
oropharynx
cavity formed by the pharynx at the back of the mouth
 
os
a mouth or mouthlike opening
 
OS
the left eye
 
os breve
a bone that is of approximately equal dimension in all directions
 
os palatinum
either of two irregularly shaped bones that form the back of the hard palate and helps to form the nasal cavity and the floor of the orbits
 
os pisiforme
a small wrist bone that articulates only with the triquetral
 
os pubis
one of the three sections of the hipbone; together these two bones form the front of the pelvis
 
os sesamoideum
any of several small round bones formed in a tendon where it passes over a joint
 
os sphenoidale
butterfly-shaped bone at the base of the skull
 
os temporale
a thick bone forming the side of the human cranium and encasing the inner ear
 
os trapezium
the wrist bone on the thumb side of the hand that articulates with the 1st and 2nd metacarpals
 
os trapezoideum
the wrist bone between the trapezium and the capitate bones
 
osmoreceptor
sensory end organ that responds to changes in osmotic pressure
 
osteophyte
small abnormal bony outgrowth
 
ostiole
a small pore especially one in the reproductive bodies of certain algae and fungi through which spores pass
 
otic ganglion
an autonomic ganglion whose postganglionic fibers are distributed to the parotid gland
 
ovarian vein
one of the veins that drain the ovaries; the right opens into the inferior vena cava; the left opens into the left renal vein
 
ovary
(vertebrates) one of usually two organs that produce ova and secrete estrogen and progesterone
 
overlip
the upper lip
 
ovipositor
egg-laying tubular structure at the end of the abdomen in many female insects and some fishes
 
ovotestis
hermaphroditic gonad that contains both testicular and ovarian tissue
 
oxtail
the skinned tail of cattle; used especially for soups
 
pad
the fleshy cushion-like underside of an animal's foot or of a human's finger
 
palaeencephalon
the more primitive parts of the brain phylogenetically; most structures other than the cerebral cortex
 
palatine vein
a vein that drains the region of the palate and empties into the facial vein
 
paleocerebellum
the anterior lobe of the cerebellum which was one of the earliest parts of the hindbrain to develop in mammals
 
palm
the inner surface of the hand from the wrist to the base of the fingers
 
pancreas
a large elongated exocrine gland located behind the stomach; secretes pancreatic juice and insulin
 
pancreatic duct
a duct connecting the pancreas with the intestine
 
pancreatic vein
veins draining the pancreas and emptying into the superior mesenteric and splenic veins
 
papilla
a small projection of tissue at the base of a hair or tooth or feather
 
papilla
a small nipple-shaped protuberance concerned with taste, touch, or smell
 
papilla
(botany) a tiny outgrowth on the surface of a petal or leaf
 
papillary muscle
any of several muscles associated with the atrioventricular valves
 
parafovea
area of the retina immediately surrounding the fovea
 
parapodium
one of a pair of fleshy appendages of a polychete annelid that functions in locomotion and breathing
 
parasympathetic
originates in the brain stem and lower part of the spinal cord; opposes physiological effects of the sympathetic nervous system: stimulates digestive secretions; slows the heart; constricts the pupils; dilates blood vessels
 
parathyroid
any one of four endocrine glands situated above or within the thyroid gland
 
paraumbilical vein
small veins arising in skin around the navel; terminate as accessory portal veins
 
parenchyma
animal tissue that constitutes the essential part of an organ as contrasted with e.g. connective tissue and blood vessels
 
parietal bone
either of two skull bones between the frontal and occipital bones and forming the top and sides of the cranium
 
parietal cortex
that part of the cerebral cortex in either hemisphere of the brain lying below the crown of the head
 
parietal gyrus
any of the convolutions of the outer surface of the parietal lobe of the cerebrum
 
parietal pericardium
the tough outermost layer of the pericardium that is attached to the diaphragm and the sternum
 
parietal pleura
pleura that lines the inner chest walls and covers the diaphragm
 
parieto-occipital fissure
a sulcus near the posterior end of each hemisphere that separates the parietal lobes and the occipital lobes in both hemispheres
 
parietomastoid suture
the suture between the parietal and the temporal bones
 
parotid gland
a large salivary gland that produces 50% of daytime saliva; in human beings it is located in front of and below each ear
 
parotid vein
parotid branches of the facial vein; they drain part of the parotid gland and empty into the retromandibular vein
 
pars anterior
the anterior part of the anterior pituitary
 
pars intermedia
a thin piece of tissue that has become part of the posterior pituitary
 
partition
(anatomy) a structure that separates areas in an organism
 
passage
a path or channel or duct through or along which something may pass
 
patent ductus arteriosus
a ductus arteriosus that failed to close at birth; may require surgical correction
 
paw
a clawed foot of an animal especially a quadruped
 
pectoral arch
the bony arch formed by the collarbones and shoulder blades in humans
 
pectoral fin
either of a pair of fins situated just behind the head in fishes that help control the direction of movement
 
pectoral girdle
a skeletal support to which the forelimbs of vertebrates are attached
 
pectoral vein
veins that drain the pectoral muscles and empty into the subclavian vein
 
pedal extremity
the extremity of the limb in vertebrates
 
peeper
an informal term referring to the eye
 
peg
informal terms for the leg
 
pellicle
thin protective membrane in some protozoa
 
pelvic cavity
the space bounded by the bones of the pelvis and containing the pelvic viscera
 
pelvic fin
either of a pair of fins attached to the pelvic girdle in fishes that help control the direction of movement; correspond to hind limbs of a land vertebrate
 
pelvis
a structure shaped like a funnel in the outlet of the kidney into which urine is discharged before passing into the ureter
 
pennon
wing of a bird
 
perforated eardrum
an eardrum with a hole or tear in it; can interfere with normal hearing and cause other ear problems
 
perforating vein
veins that accompany the perforating arteries; drain leg muscles; empty into the deep femoral vein
 
periarterial plexus
an autonomic plexus that accompanies an artery
 
pericardial cavity
the space between the layers of the pericardium that contains fluid that lubricates the membrane surfaces and allows easy heart movement
 
pericardial sac
the membrane surrounding the heart
 
pericardial vein
several small veins from the pericardium
 
pericardium
a serous membrane with two layers that surrounds the heart
 
perimysium
the sheath of connective tissue that covers a bundle of muscle fibers
 
perineum
the general region between the anus and the genital organs
 
perineurium
the sheath of connective tissue that covers a bundle of nerve fibers
 
periosteum
a dense fibrous membrane covering the surface of bones (except at their extremities) and serving as an attachment for tendons and muscles; contains nerves and blood vessels that nourish the enclosed bone
 
peripheral nervous system
the section of the nervous system lying outside the brain and spinal cord
 
peristome
(botany) fringe of toothlike appendages surrounding the mouth of a moss capsule
 
peristome
region around the mouth in various invertebrates
 
perithelium
tissue layer around small blood vessels
 
peritoneum
a transparent membrane that lines the abdominal cavity in mammals and covers most of the viscera
 
peroneus
muscle of the lower leg that is involved in moving the foot
 
Peyer's patch
any of several lymph nodes in the walls of the intestines near the junction of the ileum and colon
 
phalanx
any of the bones of the fingers or toes
 
pharyngeal vein
veins from the pharyngeal plexus that empty into the internal jugular vein
 
pharynx
the passage to the stomach and lungs; in the front part of the neck below the chin and above the collarbone
 
phrenic vein
either of two veins that drain the diaphragm
 
physiological sphincter
a sphincter that is not recognizable at autopsy because its resting arrangement cannot be distinguished from adjacent tissue
 
pia mater
the highly vascular innermost of the 3 meninges
 
pilus
hairlike structure especially on the surface of a cell or microorganism
 
pineal eye
a sensory structure capable of light reception located on the dorsal side of the diencephalon in various reptiles
 
pinguecula
a slightly elevated elastic tissue deposit in the conjunctiva that may extend to the cornea but does not cover it
 
piriform area
pear-shaped neural structure on either side of the brain in the rhinencephalon
 
placenta
the vascular structure in the uterus of most mammals providing oxygen and nutrients for and transferring wastes from the developing fetus
 
plastron
(zoology) the part of a turtle's shell forming its underside
 
plate
any flat platelike body structure or part
 
platysma
either of two broad muscles located on either side of the neck and innervated by the facial nerve; extends from lower jaw to clavicle and is involved in moving the mouth and jaw
 
pleopod
one of the paired abdominal appendages of certain aquatic crustaceans that function primarily for carrying the eggs in females and are usually adapted for swimming
 
pleura
the thin serous membrane around the lungs and inner walls of the chest
 
pleural cavity
the cavity in the thorax that contains the lungs and heart
 
plexus dentalis
a plexus of nerves serving the teeth
 
plexus pulmonalis
one of two autonomic nerve plexuses in each lung
 
plexus sacralis
a nerve plexus formed by the 4th and 5th lumbar and 1st, 2nd, 3rd sacral nerves; supplies the pelvic region and lower limbs
 
plexus
a network of intersecting blood vessels or intersecting nerves or intersecting lymph vessels
 
plica vocalis
either of two pairs of folds of mucous membrane projecting into the larynx
 
pock
a pustule in an eruptive disease
 
pocket
(anatomy) saclike structure in any of various animals (as a marsupial or gopher or pelican)
 
podetium
an organ or body resembling a stalk; especially the outgrowth of the thallus of certain lichens on which the ascocarp is borne
 
pogonion
the craniometric point that is the most forward-projecting point on the anterior surface of the chin
 
pollex
the thick short innermost digit of the forelimb
 
pons Varolii
a band of nerve fibers linking the medulla oblongata and the cerebellum with the midbrain
 
popliteal vein
a vein arising in the knee and ascending to become the femoral vein
 
pore
any small opening in the skin or outer surface of an animal
 
porta hepatis
opening for major blood vessels to enter and leave the liver
 
portacaval shunt
shunt that is created surgically between the portal vein and the inferior vena cava so that blood from the abdominal organs can bypass the liver
 
portal system
system of veins that carry blood from the abdominal organs to the liver
 
postcentral gyrus
the convolution of parietal lobe that is bounded in front by the central sulcus
 
posterior cardinal vein
a major drainage channel from the caudal part of the body
 
posterior cerebral artery
arises from the basilar artery; divides into three branches
 
posterior facial vein
posterior branch of the facial vein; formed by temporal veins in front of the ear
 
posterior labial veins
veins that pass posterior from the labia majora to the internal pudendal vein
 
posterior meningeal artery
branch of the ascending pharyngeal artery that supplies the dura mater of the posterior cranial fossa
 
posterior naris
either one of the two posterior openings at the back of the nasal cavity leading to the nasopharynx
 
posterior vein of the left ventricle
arises near the apex of the heart and empties into the coronary sinus
 
precava
receives blood from the head and arms and chest and empties into the right atrium of the heart; formed from the azygos and both brachiocephalic veins
 
precentral gyrus
the convolution of the frontal lobe that is bounded in back by the central sulcus and that contains the motor area
 
precordium
the external surface of the body overlying the heart and stomach
 
preen gland
oil-secreting gland situated at the base of the tail in most birds
 
prefrontal cortex
the anterior part of the frontal lobe
 
prehensor
the anterior pair of legs of a centipede that are modified to seize prey and inject venom from the toxicognaths
 
prepyloric vein
a tributary of the right gastric vein
 
pressure point
an area on the skin that is highly sensitive to pressure
 
pricker
a small sharp-pointed tip resembling a spike on a stem or leaf
 
proboscis
the human nose (especially when it is large)
 
proboscis
a long flexible snout as of an elephant
 
pronator
a muscle that produces or assists in pronation
 
pronucleus
the nucleus of the ovum or sperm after fertilization but before they fuse to form the nucleus of the zygote
 
prostate
a firm partly muscular chestnut sized gland in males at the neck of the urethra; produces a viscid secretion that is the fluid part of semen
 
protective fold
a flap of tissue that protects what it covers
 
prothorax
the anterior part of an insect's thorax; bears the first pair of legs
 
proud flesh
the swollen tissue around a healing wound or ulcer
 
pseudopod
temporary outgrowth used by some microorganisms as an organ of feeding or locomotion
 
psoas
either of two muscles of the abdomen and pelvis that flex the trunk and rotate the thigh
 
pterion
the craniometric point in the region of the sphenoid fontanelle
 
pterygium
either of two thickened triangular layers of conjunctiva extending from the nasal edge of the eye to the cornea; it arises from irritation of the pinguecula
 
pterygoid muscle
muscle descending from the sphenoid bone to the lower jaw
 
pterygoid plexus
a plexus of veins draining the region of the pterygoid muscles and draining into the internal maxillary and anterior facial veins
 
pterygoid process
two bony processes descending from the body of the sphenoid bone
 
pudding face
a large fat human face
 
pudendal cleavage
the fissure between the labia majora
 
pudendal vein
vein of the pudendum
 
pudendum
human external genital organs collectively especially of a female
 
pug nose
a short nose; flattened and turned up at the end
 
pulmonary trunk
the artery that carries venous blood from the right ventricle of the heart and divides into the right and left pulmonary arteries
 
pulmonary valve
a semilunar valve between the right ventricle and the pulmonary artery; prevents blood from flowing from the artery back into the heart
 
pulmonary vein
any of four veins that carry arterial blood from the lungs to the left atrium of the heart
 
pulp
the soft inner part of a tooth
 
pulp cavity
the central cavity of a tooth containing the pulp (including the root canal)
 
puppy fat
fat on the body of a baby or child; disappears at adolescence
 
Purkinje fiber
a specialized cardiac muscle fiber that is part of the Purkinje network
 
Purkinje's system
a network of Purkinje fibers that carry the cardiac impulse from the atrioventricular node to the ventricles of the heart and causes them to contract
 
pustule
a small inflamed elevation of skin containing pus; a blister filled with pus
 
putamen
the outer reddish part of the lenticular nucleus
 
pyloric vein
receives veins from the upper surfaces of the stomach and empties into the portal vein
 
pylorus
a small circular opening between the stomach and the duodenum
 
quick
any area of the body that is highly sensitive to pain (as the flesh underneath the skin or a fingernail or toenail)
 
quill
a stiff hollow protective spine on a porcupine or hedgehog
 
radial vein
superficial veins ascending the radial side of the forearm; combines with the ulnar veins to form the brachial vein
 
radiation
a radial arrangement of nerve fibers connecting different parts of the brain
 
radicle
(anatomy) a small structure resembling a rootlet (such as a fibril of a nerve)
 
radius
the outer and slightly shorter of the two bones of the human forearm
 
ramus
the posterior part of the mandible that is more or less vertical
 
rattle
loosely connected horny sections at the end of a rattlesnake's tail
 
ray
any of the stiff bony spines in the fin of a fish
 
receptor
a cellular structure that is postulated to exist in order to mediate between a chemical agent that acts on nervous tissue and the physiological response
 
receptor
an organ having nerve endings (in the skin or viscera or eye or ear or nose or mouth) that respond to stimulation
 
rectum
the terminal section of the alimentary canal; from the sigmoid flexure to the anus
 
rectus
any of various straight muscles
 
rectus superior
the ocular muscle whose contraction turns the eyeball upward and medially
 
red bone marrow
bone marrow of children and some adult bones that is required for the formation of red blood cells
 
reflex arc
the neural path of a reflex
 
renal cortex
the cortex of the kidney containing the glomeruli and the convoluted tubules
 
renal vein
veins that accompany renal arteries; open into the vena cava at the level of the 2nd lumbar vertebra
 
reproductive organ
any organ involved in sexual reproduction
 
RES
a widely distributed system consisting of all the cells able to ingest bacteria or colloidal particles etc, except for certain white blood cells
 
respiratory center
the center in the medulla oblongata and pons that integrates sensory information about the level of oxygen and carbon dioxide in the blood and determines the signals to be sent to the respiratory muscles
 
respiratory organ
any organ involved in the process of respiration
 
respiratory system
the system for taking in oxygen and giving off carbon dioxide; in terrestrial animals this is accomplished by breathing
 
rete testis
network of tubules carrying sperm from the seminiferous tubules to the vasa efferentia
 
reticulum
the second compartment of the stomach of a ruminant
 
retina
the innermost light-sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve
 
rhinion
the anterior tip at the end of the suture of the nasal bones
 
rhomboid
any of several muscles of the upper back that help move the shoulder blade
 
rib
a riblike supporting or strengthening part of an animal or plant
 
rib cage
the bony enclosing wall of the chest
 
ribosome
an organelle in the cytoplasm of a living cell; they attach to mRNA and move down it one codon at a time and then stop until tRNA brings the required amino acid; when it reaches a stop codon it falls apart and releases the completed protein molecule for use by the cell
 
ridge
any long raised border or margin of a bone or tooth or membrane
 
right atrioventricular valve
valve with three cusps; situated between the right atrium and the right ventricle; allows blood to pass from atrium to ventricle and closes to prevent backflow when the ventricle contracts
 
right brain
the cerebral hemisphere to the right of the corpus callosum that controls the left half of the body
 
right coronary artery
arises from the right aortic sinus; supplies the right side of the heart
 
right ventricle
the chamber on the right side of the heart that receives venous blood from the right atrium and pumps it into the pulmonary trunk
 
right
the hand that is on the right side of the body
 
rima
a narrow elongated opening or fissure between two symmetrical parts
 
Rolando's area
the cortical area that influences motor movements
 
Roman nose
a nose with a prominent slightly aquiline bridge
 
root
the embedded part of a bodily structure such as a tooth, nail, or hair
 
root canal
the passage in the root of a tooth through which its nerve and blood vessels enter the pulp cavity
 
rostrum
beaklike projection of the anterior part of the head of certain insects such as e.g. weevils
 
rotator cuff
a supporting structure of the shoulder consisting of the muscles and tendons that attach the arm to the shoulder joint and enable the arm to move
 
round bone
bones that are round in shape
 
rudiment
the remains of a body part that was functional at an earlier stage of life
 
ruga
(anatomy) a fold or wrinkle or crease
 
SA node
a specialized bit of heart tissue that controls the heartbeat
 
sac
a structure resembling a bag in an animal
 
saccule
a small sac or pouch (especially the smaller chamber of the membranous labyrinth)
 
sacral nerve
any of five pairs of spinal nerves emerging from the sacral region of the spinal cord
 
sacral vein
vein of the sacral region
 
sacral vertebra
one of 5 vertebrae in the human spine that fuse in the adult to form the sacrum
 
sacrum
wedge-shaped bone consisting of five fused vertebrae forming the posterior part of the pelvis; its base connects with the lowest lumbar vertebra and its tip with the coccyx
 
saddle
posterior part of the back of a domestic fowl
 
salivary duct
a duct through which saliva passes from the salivary gland into the mouth
 
salivary gland
any of three pairs of glands in the mouth and digestive system that secrete saliva for digestion
 
salpinx
a tube in the uterus or the ear
 
saphenous vein
either of two chief superficial veins of the leg that drain blood from the foot
 
sarcolemma
an extensible membrane enclosing the contractile substance of a muscle fiber
 
sarcosome
a large mitochondrion in a striated muscle fiber
 
scalp
the skin that covers the top of the head
 
scapula
either of two flat triangular bones one on each side of the shoulder in human beings
 
scar tissue
the connective tissue that forms a scar; consists of fibroblasts in new scars and collagen fibers in old scars
 
sclera
the whitish fibrous membrane (albuginea) that with the cornea forms the outer covering and protection of the eyeball
 
scleral veins
tributaries of the anterior ciliary veins that drain the sclera of the eye
 
scrotal vein
veins passing from the scrotum to the pudendal veins
 
scrotum
the external pouch that contains the testes
 
scut
a short erect tail
 
semicircular canal
one of three tube loops filled with fluid and in planes nearly at right angles with one another; concerned with equilibrium
 
semilunar valve
a heart valve with cusps shaped like half-moons; prevents blood from flowing back into the heart
 
seminal duct
the efferent duct of the testis in man
 
seminal vesicle
either of a pair of glands located on either side of the male urinary bladder that open into the vas deferens and that secrete many components of semen during ejaculation
 
seminiferous tubule
any of the numerous long convoluted tubules in the testis which are the sites where spermatozoa mature
 
semipermeable membrane
a membrane (as a cell membrane) that allows some molecules to pass through but not others
 
sensorimotor area
an area of the cortex including the precentral gyrus and the postcentral gyrus and combining sensory and motor functions
 
sensorium
the areas of the brain that process and register incoming sensory information and make possible the conscious awareness of the world
 
sensory hair
a long stiff hair growing from the snout or brow of most mammals as e.g. a cat
 
sensory system
the body's system of sense organs
 
septum
(anatomy) a dividing partition between two tissues or cavities
 
sericterium
silk-producing gland of insects (especially of a silkworm) or spiders
 
serosa
a thin membrane lining the closed cavities of the body; has two layers with a space between that is filled with serous fluid
 
serratus posterior inferior
a thin quadrilateral muscle at the junction of the thoracic and lumbar regions; acts to counteract the pull of the diaphragm on the ribs to which it is attached
 
serratus posterior superior
a thin quadrilateral muscle of the upper and dorsal part of the thorax; acts to elevate the upper ribs
 
serratus
any of several muscles of the trunk
 
seta
stalk of a moss capsule
 
seta
a stiff hair or bristle
 
shank
the part of the human leg between the knee and the ankle
 
shank's mare
you own legs
 
shin
the front part of the human leg between the knee and the ankle
 
shin
the inner and thicker of the two bones of the human leg between the knee and ankle
 
short saphenous vein
a vein running from the foot up the back of the leg to the knee
 
shoulder
the part of the body between the neck and the upper arm
 
shunt
a passage by which a bodily fluid (especially blood) is diverted from one channel to another
 
side
either the left or right half of a body
 
sigmoid colon
the s-shaped curve between the descending colon and the rectum
 
sigmoid sinus
an S-shaped dural sinus on the temporal and occipital bones
 
sigmoid vein
tributaries of the inferior mesenteric vein; drains the sigmoid colon
 
sinciput
the front part of the head or skull (including the forehead)
 
sinew
a cord or band of inelastic tissue connecting a muscle with its bony attachment
 
sinus
any of various air-filled cavities especially in the bones of the skull
 
sinus rectus
an unpaired sinus of the dura mater
 
sinus transversus
a paired dural sinus; terminates in the sigmoid sinus
 
sinus
a wide channel containing blood; does not have the coating of an ordinary blood vessel
 
sinusoid
tiny endothelium-lined passages for blood in the tissue of an organ
 
siphon
a tubular organ in an aquatic animal (especially in mollusks) through which water can be taken in or expelled
 
skeletal muscle
a muscle that is connected at either or both ends to a bone and so move parts of the skeleton; a muscle that is characterized by transverse stripes
 
skeletal structure
any structure created by the skeleton of an organism
 
skin graft
a piece of skin taken from a donor area and surgically grafted at the site of an injury or burn
 
skull
the bony skeleton of the head of vertebrates
 
small
the slender part of the back
 
small intestine
the longest part of the alimentary canal; where digestion is completed
 
smooth muscle
muscle tissue that does not appear striated under the microscope; has the form of thin layers or sheets
 
socket
a bony hollow into which a structure fits
 
soft palate
a muscular flap that closes off the nasopharynx during swallowing or speaking
 
sole
the underside of the foot
 
soleus
a broad flat muscle in the calf of the leg under the gastrocnemius muscle
 
spermatic cord
a structure resembling a cord that suspends the testis within the scrotum and contains the vas deferens and other vessels and nerves
 
sphenion
the anterior tip of the parietal bone
 
sphenoid fontanel
the irregularly shaped area on either side of the cranium where the frontal bone and the anterior tip of the parietal bone and the temporal bone and the greater wing of the sphenoid bone meet; corresponds to the pterion when bones have ossified
 
spicule
small pointed structure serving as a skeletal element in various marine and freshwater invertebrates e.g. sponges and corals
 
spinal nerve root
one of two roots of the spinal nerves
 
spinal nerve roots
either of two roots of the spinal nerves
 
spinal vein
veins that drain the spinal cord
 
spindlelegs
long thin legs
 
spine
a sharp rigid animal process or appendage; as a porcupine quill or a ridge on a bone or a ray of a fish fin
 
spiracle
a breathing orifice
 
splanchnic nerve
any of several nerves of the sympathetic part of the autonomic nervous system that innervate viscera and blood vessels
 
splenic vein
a vein formed by several small veins on the surface of the spleen; joins the superior mesenteric to form the portal vein
 
splenius
either of two flat muscles that extend from the upper vertebrae to the base of the skull and serve to rotate or flex or extend the head and neck
 
splint bone
a rudimentary metacarpal or metatarsal bone on either side of the cannon bone in the leg of a horse or related animal
 
spur
tubular extension at the base of the corolla in some flowers
 
stapes
the stirrup-shaped ossicle that transmits sound from the incus to the cochlea
 
stellate venule
a star-shaped group of venules in the renal cortex
 
stephanion
the craniometric point on the coronal suture above the acoustic meatus
 
sternocleidomastoid vein
drains the sternocleidomastoid muscle; empties into the internal jugular vein
 
stigma
an external tracheal aperture in a terrestrial arthropod
 
stinger
a sharp organ of offense or defense (as of a wasp or stingray or scorpion) often connected with a poison gland
 
stinging hair
a multicellular hair in plants like the stinging nettle that expels an irritating fluid
 
stoma
a mouth or mouthlike opening (especially one created by surgery on the surface of the body to create an opening to an internal organ)
 
stretch receptor
a receptor in a muscle that responds to stretching of the muscle tissue
 
striated muscle tissue
muscle tissue characterized by transverse stripes
 
stroma
the supporting tissue of an organ (as opposed to parenchyma)
 
stump
the part of a limb or tooth that remains after the rest is removed
 
style
a slender bristlelike or tubular process
 
stylet
small needlelike appendage; especially the feeding organ of a tardigrade
 
styloid process
extends from the base of the temporal bone
 
stylomastoid vein
a vein that drains the tympanic cavity and empties into the retromandibular vein
 
subclavian vein
a continuation of the axillary vein; joins the internal jugular to form the brachiocephalic vein
 
sublingual gland
a small salivary gland that produces mucin (the viscous component of saliva); in human beings it is located on either side of the mouth under the tongue
 
sublingual vein
a tributary of the lingual vein
 
submucosa
the connective tissue beneath mucous membrane
 
substantia alba
whitish nervous tissue of the CNS consisting of neurons and their myelin sheaths
 
subthalamic nucleus
an oval mass of grey matter located in the caudal part of the subthalamus; associated with the striate body
 
subthalamus
the ventral part of the thalamus
 
sucker
an organ specialized for sucking nourishment or for adhering to objects by suction
 
sudoriferous gland
any of the glands in the skin that secrete perspiration
 
sulcus
(anatomy) any of the narrow grooves in an organ or tissue especially those that mark the convolutions on the surface of the brain
 
superciliary arch
a ridge on the frontal bone above the eye socket
 
superficial epigastric vein
empties into the great saphenous vein
 
superficial middle cerebral vein
a large vein along the line of the Sylvian fissure to the cavernous sinus
 
superficial temporal vein
join the middle temporal vein to empty into the retromandibular vein
 
superior cerebellar artery
the superior branch of the cerebellar artery
 
superior cerebral vein
a cerebral vein that drains the dorsal convexity of the cerebral hemisphere and empties into the cavernous sinus
 
superior colliculus
an essential visual center between the retina and the striate cortex
 
superior epigastric veins
veins that accompany the superior epigastric artery
 
superior labial vein
a tributary of the facial vein that drains the upper lip
 
superior mesenteric artery
originates from the upper part of the aorta that supplies the small intestines and the cecum and the colon
 
superior ophthalmic vein
a vein that begins at the inner angle of the eye socket and passes through the superior orbital fissure to empty into the cavernous sinus
 
superior pulmonary vein
either of two pulmonary veins (left and right) returning blood from the superior lobes of the lungs
 
superior thalamostriate vein
a long vein that helps to form the internal cerebral vein
 
superior thyroid vein
a vein on each side that drains the upper part of the thyroid and empties into the internal jugular vein
 
supinator
a muscle (especially in the forearm) that produces or assists in supination
 
supraorbital vein
drains the front of the scalp; unites with the supratrochlear vein to form the angular vein
 
supratrochlear vein
drains the front of the scalp; unites with the supraorbital vein to form the angular vein
 
sweat duct
a small duct that conveys sweat from a sudoriferous gland to the surface of the skin
 
Sylvian aqueduct
a canal connecting the third and fourth ventricles
 
sympathetic nervous system
originates in the thoracic regions of the spinal cord; opposes physiological effects of the parasympathetic: reduces digestive secretions; speeds the heart; contracts blood vessels
 
symphysion
the most forward point of the alveolar process of the mandible
 
synovial membrane
a thin membrane in synovial (freely moving) joints that lines the joint capsule and secretes synovial fluid
 
syrinx
the vocal organ of a bird
 
system
a group of physiologically or anatomically related organs or parts
 
tail
the posterior part of the body of a vertebrate especially when elongated and extending beyond the trunk or main part of the body
 
talon
a sharp hooked claw especially on a bird of prey
 
taret organ
(endocrinology) organ most affected by a particular hormone
 
target organ
(radiology) organ intended to receive the therapeutic dose of a radioactive substance
 
tarsal
any bone of the tarsus
 
tarsus
the part of the foot of a vertebrate between the metatarsus and the leg; in human beings the bones of the ankle and heel collectively
 
telencephalon
the anterior division of the forebrain; the cerebrum and related parts of the hypothalamus
 
temple
the flat area on either side of the forehead
 
temporal artery
any of the three arteries on either side of the brain supplying the cortex of the temporal lobe
 
temporal cortex
that part of the cerebral cortex in either hemisphere of the brain lying inside the temples of the head
 
temporal gyrus
any of the convolutions of the outer surface of the temporal lobe of the cerebrum
 
temporal vein
any of several veins draining the temporal region
 
tendon of Achilles
a large tendon that runs from the heel to the calf
 
tensor
any of several muscles that cause an attached structure to become tense or firm
 
tensor tympani
a small muscle in the middle ear that tenses to protect the eardrum
 
tentacle
any of various elongated tactile or prehensile flexible organs that occur on the head or near the mouth in many animals; used for feeling or grasping or locomotion
 
tentorium
(anatomy) a fold of dura mater that covers the cerebellum and supports the occipital lobes of the cerebrum
 
teres
either of two muscles in the shoulder region that move the shoulders and arms
 
testicular vein
a vein from the testicles
 
thalamostriate vein
a vein serving the thalamus and corpus striatum
 
thalamus
large egg-shaped structures of grey matter that form the dorsal subdivision of the diencephalon
 
thenar
the fleshy area of the palm at the base of the thumb
 
thermoreceptor
a sensory receptor that responds to heat and cold
 
thick skin
skin that is very thick (as an elephant or rhinoceros)
 
thigh
the part of the leg between the hip and the knee
 
third ventricle
a narrow ventricle in the midplane below the corpus callosum; communicates with the fourth ventricle via the Sylvian aqueduct
 
thoracic aorta
a branch of the descending aorta; divides into the iliac arteries
 
thoracic duct
the major duct of the lymphatic system
 
thoracic nerve
any of twelve pairs of spinal nerves emerging from the thoracic region of the spinal cord
 
thoracic vein
veins that drain the thoracic walls
 
thoracoepigastric vein
a vein arising from the region of the superficial epigastric vein and opening into the axillary vein or thoracic vein
 
thorax
part of an insect's body that bears the wings and legs
 
thorax
the middle region of the body of an arthropod between the head and the abdomen
 
throat
the part of an animal's body that corresponds to a person's throat
 
thumbnail
the nail of the thumb
 
thymus
a ductless glandular organ at the base of the neck that produces lymphocytes and aids in producing immunity; atrophies with age
 
thyroid vein
any of several small veins draining blood from the thyroid area
 
thyroid
located near the base of the neck
 
tibial vein
veins of the lower leg; empty into the popliteal vein
 
tibialis anterior
a muscle running from the tibia to the first metatarsal and cuneiform bones
 
tibialis posterior
a deep muscle of the leg
 
tissue
part of an organism consisting of an aggregate of cells having a similar structure and function
 
toe
one of the digits of the foot
 
toe
forepart of a hoof
 
toenail
the nail at the end of a toe
 
tomentum
a network of tiny blood vessels between the cerebral surface of the pia mater and the cerebral cortex
 
tooth
hard bonelike structures in the jaws of vertebrates; used for biting and chewing or for attack and defense
 
tooth
toothlike structure in invertebrates found in the mouth or alimentary canal or on a shell
 
topknot
showy crest or knot of hair or feathers
 
toxicognath
either of a pair of poison fangs in the modified front pair of legs of the centipede
 
trabecula
rod-shaped structures of fibrous tissue that divide an organ into parts (as in the penis) or stabilize the structure of an organ (as in the spleen)
 
trachea
one of the tubules forming the respiratory system of most insects and many arachnids
 
trachea
membranous tube with cartilaginous rings that conveys inhaled air from the larynx to the bronchi
 
tracheal vein
several small veins from the trachea
 
tract
a system of body parts that together serve some particular purpose
 
tragus
a small cartilaginous flap in front of the external opening of the ear
 
transverse colon
the part of the large intestine that extends across the abdominal cavity and joins the ascending to the descending colon
 
transverse process
one of two processes that extend from each vertebra and provide the point of articulation for the ribs
 
triceps
any skeletal muscle having three origins (but especially the triceps brachii)
 
trochanter
one of the bony prominences developed near the upper extremity of the femur to which muscles are attached
 
trophoblast
the membrane that forms the wall of the blastocyst in early development; aids implantation in the uterine wall
 
trotter
foot of a pig or sheep especially one used as food
 
true rib
one of the first seven ribs in a human being which attach to the sternum
 
tube foot
tentacular tubular process of most echinoderms (starfish and sea urchins and holothurians) having a sucker at the end and used for e.g. locomotion and respiration
 
tube
(anatomy) any hollow cylindrical body structure
 
tubular cavity
a cavity having the shape of a tube
 
tubule
a small tube
 
tuft
a bunch of feathers or hair
 
tunica albuginea testes
whitish cover of the testicle
 
turbinal
any of the scrolled spongy bones of the nasal passages in man and other vertebrates
 
tusk
a long pointed tooth specialized for fighting or digging; especially in an elephant or walrus or hog
 
tympanic bone
the bone enclosing the middle ear
 
tympanic vein
veins from the tympanic cavity that empty into the retromandibular vein
 
ulnar vein
any of several veins of the forearm
 
umbilical vein
a vein in the umbilical cord; returns nutrient blood from the placenta to the fetus
 
umbilical vesicle
membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional
 
umbilical
membranous duct connecting the fetus with the placenta
 
underbelly
the soft belly or underside of an animal's body
 
underlip
the lower lip
 
underpart
a part lying on the lower side or underneath an animal's body
 
undescended testicle
a testis that fails to move into the scrotum as the male fetus develops
 
upper respiratory tract
the nose and throat and trachea
 
ureter
either of a pair of thick-walled tubes that carry urine from the kidney to the urinary bladder
 
urethra
duct through which urine is discharged in most mammals and which serves as the male genital duct
 
urinary bladder
a membranous sac for temporary retention of urine
 
urinary tract
the organs and tubes involved in the production and excretion of urine
 
urochord
a notochord of a larval tunicate typically confined to the caudal region
 
uropygium
posterior part of a bird's body from which the tail feathers grow
 
uterine cavity
the space inside the uterus between the cervical canal and the Fallopian tubes
 
uterine vein
one of two veins on each side that arise from the uterine plexus and empty into the internal iliac vein
 
uterus
a hollow muscular organ in the pelvic cavity of females; contains the developing fetus
 
utricle
a small pouch into which the semicircular canals open
 
uvea
the part of the eye that contains the iris and ciliary body and choroid
 
uveoscleral pathway
a tubule that drains excess aqueous humor
 
uvula
a small pendant fleshy lobe at the back of the soft palate
 
vacuole
a tiny cavity filled with fluid in the cytoplasm of a cell
 
vagina
the lower part of the female reproductive tract; a moist canal in female mammals extending from the labia minora to the uterus
 
valve
a structure in a hollow organ (like the heart) with a flap to insure one-way flow of fluid through it
 
valvelet
a small valve
 
vane
the flattened weblike part of a feather consisting of a series of barbs on either side of the shaft
 
varicose vein
a vein that is permanently dilated; most common in the legs
 
vas
a tube in which a body fluid circulates
 
vasa efferentia
the several highly convoluted tubules that lead from the rete testis to the vas deferens and form the head of the epididymis
 
vasa vasorum
any small blood vessel ramifying on the outside of a major artery or vein
 
vascular structure
a structure composed of or provided with blood vessels
 
vascular system
the vessels and tissue that carry or circulate fluids such as blood or lymph or sap through the body of an animal or plant
 
vegetation
an abnormal growth or excrescence (especially a warty excrescence on the valves of the heart)
 
vein of penis
a vein serving the penis
 
vein
a blood vessel that carries blood from the capillaries toward the heart
 
vena bulbi penis
vein of the head of the penis; tributary of the internal pudendal vein that drains the perineum
 
vena bulbi vestibuli
vein of the vestibular bulb
 
vena canaliculi cochleae
vein of the cochlear canal
 
vena cava
either of two large veins that return oxygen-depleted blood to the right atrium of the heart
 
vena dorsalis clitoridis profunda
deep dorsal vein of the clitoris; tributary of the vesical venous plexus
 
vena profunda penis
deep vein of the penis; enters the prostatic plexus
 
vena vertebralis
a vein that goes through the foramina of the cervical vertebrae and forms a plexus around the vertebral artery; empties into the brachiocephalic vein
 
vena vesicalis
veins that drain the vesical plexus and join the internal iliac veins
 
vena vestibularis
veins that drain the saccule and utricle
 
vena vorticosum
a vein formed by branches from the back surface of the eye and the ciliary body; empties into the ophthalmic veins
 
venae dorsales clitoridis superficiales
superficial dorsal veins of the clitoris; tributaries of the external pudendal vein on either side
 
venae dorsales penis profunda
deep dorsal vein of the penis; tributary of the prostatic plexus
 
venae dorsales penis superficiales
superficial dorsal veins of the penis; paired tributaries of the external pudendal veins on each side
 
venae interlobulares hepatis
interlobular veins of the liver
 
venae interlobulares renis
interlobular veins of the kidney; receive blood from the arcuate vein and empty into the renal veins
 
venae palpebrales
veins of the eyelids
 
venae profundae clitoridis
deep veins of the clitoris; join the vesical plexus
 
venae renis
veins of the kidney; drain the kidney into the renal vein
 
venation
(zoology) the system of venous blood vessels in an animal
 
vent
external opening of urinary or genital system of a lower vertebrate
 
venter
a bulging body part (as the belly of a muscle)
 
venter
the womb
 
ventricle
one of four connected cavities in the brain; is continuous with the central canal of the spinal cord and contains cerebrospinal fluid
 
vermis
the narrow central part of the cerebellum between the two hemispheres
 
vertebra
one of the bony segments of the spinal column
 
vestibular apparatus
organs mediating the labyrinthine sense; concerned with equilibrium
 
vestibular gland
a gland that opens into the vestibule of the vagina; secretions lubricate the vagina during coitus
 
vestibule
any of various bodily cavities leading to another cavity (as of the ear or vagina)
 
vestibule of the ear
the central cavity of the bony labyrinth of the ear
 
vestibule of the vagina
the space between the labia minora containing the orifice of the urethra
 
villus
a minute hairlike projection on mucous membrane
 
visceral pleura
pleura that covers the lungs
 
visual area
the cortical area that receives information from the lateral geniculate body of the thalamus
 
visual system
the sensory system for vision
 
vital organ
a bodily organ that is essential for life
 
voluntary muscle
striated muscle that can be controlled voluntarily
 
vomer
thin trapezoidal bone of the skull forming the posterior and inferior parts of the nasal septum
 
vulva
external parts of the female genitalia
 
waist
the narrowing of the body between the ribs and hips
 
wasp waist
a very slender waist
 
water blister
blister containing a nonpurulent clear watery content
 
water vascular system
system of fluid-filled tubes used by echinoderms in locomotion and feeding and respiration
 
web
membrane connecting the toes of some aquatic birds and mammals
 
webbed foot
a bird's foot with folds of skin between the toes
 
webfoot
a foot having the toes connected by folds of skin
 
Wernicke's center
the auditory word center; located in the posterior part of the superior temporal convolution in most people
 
wing
a movable organ for flying (one of a pair)
 
wisdom tooth
any of the last 4 teeth on each side of the upper and lower jaw; the last of the permanent teeth to erupt (between ages 16 and 21)
 
wishbone
the furcula of a domestic fowl
 
withers
the highest part of the back at the base of the neck of various animals especially draft animals
 
Wormian bone
any of the tiny soft bones found in the sutures between cranial bones
 
xiphoid process
smallest of the three parts of the breastbone; articulates with the corpus sternum and the seventh rib
 
yellow bone marrow
bone marrow that is yellow with fat; found at the ends of long bones in adults
 
yolk sac
membranous structure enclosing the yolk of eggs in birds, reptiles, marsupials, and some fishes; circulates nutrients to the developing embryo
 
zona pellucida
thick membrane around the mammalian ovum; can be penetrated by one sperm in the fertilization process; usually remains around the fertilized egg until it is implanted in the wall of the uterus
 
zona
(anatomy) any encircling or beltlike structure
 
zonula
small beltlike zone
 
zygodactyl foot
a bird's foot having the first and fourth toes of each foot directed backward and the second and third forward
 
zygomatic process
a slender process of the temporal bone that strengthens the zygomatic arch