abdomen
(ab´duo-men, ab-do´men) the portion of the trunk between the diaphragm and pelvis.
abduction
(ab-duk´shun) the movement of a body part away from the axis or midline of the body; movement of a digit away from the axis of the limb.
absorption
(ab-sorp´shun) the transport of molecules across epithelial membranes into the body fluids.
accessory organs
(ak-ses´uo-re) organs that assist with the functioning of other organs within a system.
accommodation
(ua-kom´´uo-da´shun) a process whereby the focal length of the eye is changed by automatic adjustment of the curvature of the lens to bring images of objects from various distances into focus on the retina.
acetabulum
(as´´ue-tab´yuu-lum) a socket in the lateral surface of the hipbone (os coxa) with which the head of the femur articulates. (see ilium, ischium, pubis)
achilles tendon
(ua-kil´=ez) see tendo calcaneous.
acromegaly
(ak´´ro-meg´ua-le) a condition caused by the hypersecretion of growth hormone from the pituitary gland after maturity and characterized by enlargement of the extremities, such as the nose, jaws, fingers, and toes.
acromion
greek akros = summit (cf. acropolis) and omos = shoulder, hence, the tip of the shoulder.
adduction
(au-duk´shun) the movement of a body part toward the axis or midline of the body; movement of a digit toward the axis of the limb.
adenoids
(ad´ue-noidz) the tonsils located in the nasopharynx; pharyngeal tonsils.
adhesion
latin ad = to, and haesus = stuck, hence, stuck to
adventitia
(ad´´ven-tish´ua) the outermost epithelial layer of a visceral organ; also called serosa.
afferent
(af´er-ent) conveying or transmitting to.
afferent arteriole
(ar-tir´e-=ol) a blood vessel within the kidney that supplies blood to the glomerulus.
afferent neuron
(noor´on) see sensory neuron.
albumin
(al-byoo´min) a water-soluble protein produced in the liver; the major component of the plasma proteins.
alimentary canal
the tubular portion of the digestive tract. see also gastrointestinal tract (gi tract).
allantois
(ua-lan´to-is) an extraembryonic membranous sac involved in the formation of blood cells. it gives rise to the fetal umbilical arteries and vein and also contributes to the formation of the urinary bladder.
alveolar sacs
(al-ve´uo-lar) a cluster of alveoli that share a common chamber or central atrium.
alveolus
(al-ve´uo-lus) two meanings; 1.an individual air capsule within the lung. the alveoli are the basic functional units of respiration. 2.the socket that secures a tooth (tooth socket).
amniocentesis
(am´´ne-o-sen-te´sis) a procedure in which a sample of amniotic fluid is aspirated to examine suspended cells for various genetic diseases.
amnion
(am´ne-on) a developmental membrane surrounding the fetus that contains amniotic fluid.
amphiarthrosis
(am´´fe-ar-thro´sis) a slightly movable articulation in a functional classification of joints.
ampulla
(am-pool´ua) latin = a two-handed flask, a local dilatation of a duct or tube.
ampulla of vater
(fua´ter) see hepatopancreatic ampulla.
anal canal
(a´nal) the terminal tubular portion of the large intestine that opens through the anus of the gi tract.
anastomosis
(ua-nas´tuo-mo´sis) an interconnecting aggregation of blood vessels or nerves that form a network plexus.
anatomical position
(an´´ua-tom´u1-kal) an erect body stance with the eyes directed interior, the arms at the sides, the palms of the hands facing interior, and the fingers pointing straight down.
anatomy
(ua-nat´uo-me) the branch of science concerned with the structure of the body and the relationship of its organs.
anemia
(ua-ne´me-ua) an abnormal reduction in the red blood cell count, hemoglobin concentration, or hematocrit, or any combination of these measurements. this condition is associated with a decreased ability of the blood to carry oxygen.
angina pectoris
(an-ji´nua pek´tuo-ris) a thoracic pain, often referred to the left pectoral and arm area, caused by myocardial ischemia.
annulus fibrosus
tough hyaline cartilaginous rim of an intervertebral disc (see nucleus pulposus)
antebrachium
(an´´te-bra´ke-em) the forearm.
anteflexion
the forward angle of the normal uterus on the cervix. (see anteversion, retroflexion, retroversion)
anterior
(ventral) toward the front; the opposite of posterior, or dorsal.
anterior pituitary
(pu1-too´u1-ter-e) see adenohypophysis.
anterior root
the anterior projection of the spinal cord, composed of axons of motor neurons.
anteversion
the forward bending position of the normal uterus on the backward sloping vagina. (see anteflexion, retroversion, retroflexion)
antrum
greek antron = cave, hence a space in a bone or organ
anus
(a´nus) the terminal opening of the gi tract.
aorta
(a-or´tua) the major systemic vessel of the arterial system of the body, emerging from the left ventricle.
aortic arch
the superior left bend of the aorta between the ascending and descending portions.
apex
(a´peks) the tip or pointed end of a conical structure.
apneustic center
(ap-noo´stik) a collection of nuclei(nerve cell bodies) in the brain stem that participates in the rhythmic control of breathing.
apocrine gland
(ap´uo-krin) a type of sweat gland that functions in evaporative cooling. it may respond during periods of emotional stress.
aponeurosis
(ap´´uo-noo-ro´sis) greek apo = from, and neuron = tendon (later applied to nerve cell and its fibres), fibrous or membranous sheet like tendon.
appendix
a short pouch that attaches to the cecum.
appendicular
latin appendere = to hang on, supplement.
aqueous humor
(a´kwe-us) the watery fluid that fills the anterior and posterior chambers of the eye.
arachnoid mater
(ua-rak´noid) the weblike (greek: arakhnes=spider) middle covering (meninx) of the central nervous system. joined to the pia mater by thin strands of tissue and covered by the dura mata (see meninges)
arbor vitae
(ar´bor vi´te) the branching arrangement of white matter within the cerebellum.
arm
the portion of the upper extremity from the shoulder to the elbow. (see brachium, forearm, antibrachium)
arrector pili muscle
(ah-rek´tor pih´le) the smooth muscle attached to a hair follicle that, upon contraction, pulls the hair into a more vertical position, resulting in "goose bumps."
arteriole
(ar-tir´e-=ol) a minute arterial branch.
arteriosclerosis
(ar-tir´´e-o-sklue-ro´sis) any one of a group of diseases characterized by thickening and hardening of the artery wall and in the narrowing of its lumen.
arteriovenous anastomoses
(ar-tir´´e-o-ve´nus ua-nas´´tuo-mo´s=ez) direct connections between arteries and veins that bypass capillary beds.
artery
(ar´tue-re) a blood vessel that carries blood away from the heart.
arthrology
(ar-throl´uo-je) the scientific study of the structure and function of joints.
articular cartilage
(ar-tik´yuu-lar kar´tu1-lij) a hyaline cartilaginous covering over the articulating surface of the bones of synovial joints.
articulation
(ar-tik´´yuu-la´shun) a joint.
arytenoid cartilages
(ar´´ue-te´noid) a pair of small cartilages located on the superior aspect of the larynx.
ascending colon
(ko´lon) the portion of the large intestine between the cecum and the hepatic flexure.
astigmatism
(ua-stig´mua-tiz´´em) unequal curvature of the refractive surfaces of the eye (cornea and/or lens), so that light entering the eye along certain meridians does not focus on the retina.
atherosclerosis
(ath´´ue-ro-sklue-ro´sis) a common type of arteriosclerosis found in medium and larger arteries in which raised areas within the tunica intima are formed from smooth muscle cells, cholesterol, and other lipids. these plaques occlude arteries and serve as sites for the formation of thrombi.
atresia
greek a = negative, and tresis = a hole, hence an absence or closure of a body orifice or tubular organ.
atretic
(ua-tret´ik) without an opening. atretic ovarian follicles are those that fail to ovulate.
atrioventricular bundle
(a´´tre-o-ven-trik´yuu-lar) a group of specialized cardiac fibers that conduct impulses from the atrioventricular node to the ventricular muscles of the heart; also called the bundle of his or av bundle.
atrioventricular node
(a microscopic aggregation of specialized cardiac fibers located in the interatrial septum of the heart that are a part of the conduction system of the heart; av node.
atrioventricular valve
(a cardiac valve located between an atrium and a ventricle of the heart; av valve.
atrium
(a´tre-um) latin = entrance hall; either of the two superior chambers of the heart that receive venous blood.
atrophy
(at´ruo-fe) a gradual wasting away or decrease in the size of a tissue or an organ.
attachments
may mean either an origin or insertion of a muscle. the tedious memorising of origins and insertions is quite unnecessary
auditory
(aw´du1-tor-e) pertaining to the structures of the ear associated with hearing.
auditory tube
a narrow canal that connects the middle ear chamber to the pharynx; also called the eustachian canal.
auricle
(or´1u-kul) two meanings; 1.the fleshy pinna of the ear. 2. an ear-shaped appendage of each atrium of the heart.
auscultating
latin ausculto = to listen to, hence, auscultation, the act of listening to a bodily activity.
autonomic nervous system
(aw´´tuo-nom´ik) the sympathetic and parasympathetic portions of the nervous system that function to control the actions of the visceral organs and skin; ans.
axial
synonymous with transverse plane
axilla
(ak-sil´ua) the depressed hollow commonly called the armpit.
axon
(ak´son) the elongated process of a nerve cell that transmits an impulse away from the cell body of a neuron.
ball-and-socket joint
(The most freely movable type of synovial joint(e.g., the shoulder or hip joint).
basal nucleus
(ba´sal noo´kle-us) A mass of nerve cell bodies located deep within a cerebral hemisphere of the brain; also called basal ganglion.
belly
The thickest circumference of a skeletal muscle.
benign
(b1u-n=1n´) Not malignant.
bifid
Latin bis = double, and findo = to split
bifurcate
(bi´fur-k=at) Forked; divided into two branches.
bile
A liver secretion that is stored and concentrated in the gallbladder and released through the common bile duct into the duodenum. It is essential for the absorption of fats.
bilirubin
(bil´´u1-roo´bin) Bile pigment derived from the breakdown of the heme portion of hemoglobin.
bipennate
(bi-pen´=at) Latin bis = double, and pinna = feather, hence converging from 2 sides; Denoting muscles that have a fibre architecture coursing obliquely on both sides of a tendon.
blood
(The fluid connective tissue that circulates through the cardiovascular system to transport substances throughout the body.
blood-brain barrier
A specialized mechanism, not a structure, that inhibits the passage of certain materials from the blood into brain tissue and cerebrospinal fluid.
bolus
(bo´lus) A moistened mass of food that is swallowed from the oral cavity into the pharynx.
bone
A solid, rigid, ossified connective tissue forming an organ of the skeletal system.
bony labyrinth
(lab´u1-rinth) A series of chambers within the petrous part of the temporal bone associated with the vestibular organs and the cochlea. The bony labyrinth contains a fluid called perilymph.
brachial
(bra´ke-al) Pertaining to the arm (shoulder-elbow).
brachial plexus
(bra´ke-al plek´sus) A network of nerve fibers that arise from spinal nerves C5-C8 and T1. Nerves arising from the brachial plexuses supply the upper extremities.
brain
The enlarged superior portion of the central nervous system located in the cranial cavity of the skull.
brain stem
The portion of the brain consisting of the medulla oblongata, pons, and midbrain.
branchial
Associated with the entrance to the digestive system.
brevis
Latin = short - cf. brief
bronchial tree
(brong´ke-al) The bronchi and their branching bronchioles.
bronchiole
(brong´ke-=ol) A small division of a bronchus within the lung.
bronchus
(brong´kus) A branch of the trachea that leads to a lung.
buccal cavity
(buk´al) Latin bucca = cheek; The mouth, or oral cavity.
bulbourethral glands
(bul´´bo-yoo-re´thral) A pair of glands that secrete a viscous fluid into the male urethra during sexual excitement; also called Cowper's glands.
bundle of His
See atrioventricular bundle
bursa
(bur´sa) Greek = a purse, hence a flattened sac containing a film of fluid (synovial fluid). Bursae are located at friction points, as around joints, over which tendons can slide without contacting bone.
buttocks
(but´oks) The rump or fleshy masses on the posterior aspect of the lower trunk, formed primarily by the gluteal muscles.
CABG
coronary artery bypass graft
caecum
(se´kum) latin = blind; the pouch like portion of the large intestine to which the ileum of the small intestine is attached.
calyx
(ka´liks) a cup-shaped portion of the renal pelvis that encircles a renal papilla.
calcaneus
latin calx = heel, hence the bone of the heel.
calcar avis
latin the spur of a bird, hence a spur-like elevation.
calcarine
latin calcar = spur, hence spur-shaped.
calf
the soft tissue swelling at the back of the leg.
callosum
latin callum = hard.
calvaria
latin calva = bald head, hence the part of the skull containing the brain - i.e. cranium minus the facial skeleton.
calyx
latin = a wine-cup (plural - calyces).
canaliculus
(kan´´ua-lik´yuu-lus) a microscopic channel in bone tissue that connects lacunae.
canal of schlemm
(shlem) see scleral venous sinus.
cancer
(a tumor characterized by abnormally rapid cell division and the loss of specialized tissue characteristics. this term usually refers to malignant tumors.
cancellous
adjective, latin cancelli = grating or lattice. (see cortical, trabeculea)
canthus
greek kanthos - used at first for rim of eye, then angle between ends of rims
capillary
(kap´u1-lar´´e) latin capillaris = hair-like. a microscopic blood vessel that connects an arteriole and a venule; the functional unit of the circulatory system.
capitate
adjective, having a caput from Latin capitis = of a head (q.v.).
capitulum
diminutive of caput, Latin = head.
capsule
Latin capsa = box, hence an enclosing sheet.
carcinoma
cancer of the epithelial (rather than connective tissue) origin
cardiac muscle
(kar´de-ak) muscle of the heart, consisting of striated muscle cells. these cells are interconnected into a mass called the myocardium.
cardiac output
the volume of blood pumped per minute by either the right or left ventricle.
cardiac tamponade
cardiac tamponade is a life-threatening condition caused by fluid under pressure around the heart. fluid that collects in the pericardial sac (the tissue sac in which the heart lies) can develop enough pressure to prevent the heart from relaxing completely between beats. usually, this fluid has accumulated rapidly, and the increase in pericardial pressure causes a sudden decrease in cardiac output
cardiogenic shock
(kar´´de-o-jen´ik) shock that results from low cardiac output in heart disease.
carotid sinus
(kua-rot´id) an expanded portion of the internal carotid artery located immediately above the point of branching from the external carotid artery. the carotid sinus contains baroreceptors that monitor blood pressure.
carpus
(kar´pus) greek=wrist. the proximal portion of the hand that contains the eight carpal bones.
cartilage
(kar´tu1-lij) latin = gristle; a type of connective tissue with a solid elastic matrix.
cartilaginous joint
(kar´´tu1-laj´u1-nus) a joint that lacks a joint cavity, permitting little movement between the bones held together by cartilage.
cauda equina
(kaw´dua e-kwi´nua) the lower end of the spinal cord where the roots of spinal nerves have a tail-like appearance.
caudal
(kaw´dual) nearer the tail (or where it would be). the kidneys are caudal to the diaghpram.
cell
the structural and functional unit of an organism; the smallest structure capable of performing all the functions necessary for life.
cementum
(se-men´tum) bone like material that binds the root of a tooth to the periodontal membrane of the bony socket.
central canal
an elongated longitudinal channel in the centre of an osteon in bone tissue that contains branches of the nutrient vessels and a nerve; also called a haversian canal.
central nervous system
part of the nervous system consisting of the brain and the spinal cord; cns.
cephalic
(nearer to, or pertaining to the head.
cerebellar peduncle
(ser´´ue-bel´ar pue-dung´k'l) an aggregation of nerve fibers connecting the cerebellum with the brain stem.
cerebellum
(ser´´ue-bel´um) the portion of the brain concerned with the coordination of skeletal muscle contraction. part of the metencephalon, it consists of two hemispheres and a central vermis.
cerebral arterial circle
(ser´ue-bral) an arterial vessel that encircles the pituitary gland. it provides alternate routes for blood to reach the brain should a carotid or vertebral artery become occluded; also called the circle of willis.
cerebral peduncles
a paired bundle of nerve fibers along the inferior surface of the midbrain that conduct impulses between the pons and the cerebral hemispheres.
cerebrospinal fluid
(ser´´ue-bro-spi´nal) a fluid produced by the choroid plexus of the ventricles of the brain. it fills the ventricles and surrounds the central nervous system in association with the meninges.
cerebrum
(ser´ue-brum) the largest portion of the brain, composed of the right and left hemispheres.
ceruminous gland
(sue-roo´mu1-nus) a specialized integumentary gland that secretes cerumen, or earwax, into the external auditory canal.
cervical
(ser´vu1-kal) pertaining to the neck or a necklike portion of an organ.
cervical ganglion
(gang´gle-on) a cluster of postganglionic sympathetic nerve cell bodies located in the neck, near the cervical vertebrae.
cervical plexus
(plek´sus) a network of spinal nerves formed by the anterior branches of the first four cervical nerves.
cervix
(ser´viks) latin = neck; 1.the narrow neck like portion of an organ. 2.the inferior end of the uterus that adjoins the vagina (cervix of the uterus).
cheyne-stokes respiration
(ch=an´st=okes´ res´´pu1-ra´shun) breathing characterized by rhythmic waxing and waning of the depth of respiration, with regularly occurring periods of apnea (failure to breathe).
chiasma
(ki-as´mua) a crossing of nerve tracts from one side of the cns to the other; also called a chiasm.
choanae
(ko-a´ne) greek = funnel, plural - choanae; the two posterior openings from the nasal cavity into the nasal pharynx; also called the internal nares.
chondrocranium
(kon´´dro-kra´ne-um) the portion of the skull that supports the brain. it is derived from endochondral bone.
chordae tendineae
(kor´de ten-din´e-e) chordlike tendinous bands that connect papillary muscles to the leaflets of the atrioventricular valves within the ventricles of the heart.
chorea
(kuo-re´-ua) the occurrence of a wide variety of rapid, complex, jerky movements that appear to be well coordinated but that are performed involuntarily.
chorion
an extraembryonic membrane that participates in the formation of the placenta.
choroid
(kor´oid) adjective, greek chorion = skin and eidos = shape or form, hence, like a membrane
choroid plexus
a mass of vascular capillaries from which cerebrospinal fluid is secreted into the ventricles of the brain.
chyme
(k=1m) chyle: greek = juice. chyli:greek = juice; the mass of partially digested food that passes from the pylorus of the stomach into the duodenum of the small intestine.
cilia
(sil´e-ua) latin cilia = eyelashes; microscopic hair like processes that move in a wavelike manner on the exposed surfaces of certain epithelial cells.
ciliary body
(sil´e-er´´e) a portion of the choroid layer of the eye that secretes aqueous humor. it contains the ciliary muscle.
circadian rhythms
(ser´´kua-de´an) physiological changes that repeat at about 24-hour intervals. these are often synchronized with changes in the external environment, such as the day-night cycles.
circle of willis
see cerebral arterial circle.
circumduction
(ser´´kum-duk´shun) a movement of a body part that outlines a cone, such that the distal end moves in a circle while the proximal portion remains relatively stable.
cirrhosis
(su1-ro´sis) liver disease characterized by loss of normal microscopic structure, which is replaced by fibrosis and nodular regeneration.
clavicle
diminutive of latin clavis = key - old roman key was s-shaped
clitoris
(klit´or-is, kli´tor-is) a small, erectile structure in the vulva of the female, homologous to the glans penis in the male.
cns
(see central nervous system.)
coccygeal
(kok-sij´e-al) pertaining to the region of the coccyx; the caudal termination of the vertebral column.
cochlea
(kok´le-ua) the organ of hearing in the inner ear where nerve impulses are generated in response to sound waves.
cochlear window
see round window.
coelom
(se´lom) greek koilos = a hollow; the abdominal cavity.
collateral
(kuo-lat´er-al) a small branch of a blood vessel or nerve fiber.
colon
(ko´lon) the first portion of the large intestine.
common bile duct
a tube formed by the union of the hepatic duct and cystic duct that transports bile to the duodenum.
compact bone
tightly packed bone that is superficial to spongy bone and covered by the periosteum; also called dense bone.
condyle
(kon´d=1l) greek kondylos = knuckle; a rounded process at the end of a long bone that forms an articulation.
cone
a color receptor cell in the retina of the eye.
congenital
(kon-jen´u1-tal) present at the time of birth.
congestive heart failure
(kon-jes´tiv) the inability of the heart to deliver an adequate blood flow as a result of heart disease or hypertension. this condition is associated with breathlessness, salt and water retention, and oedema.
conjunctiva
(kon´´jungk-ti´vua) the thin membrane covering the anterior surface of the eyeball and lining the eyelids.
connective tissue
one of the four basic tissue types within the body. it is a binding and supportive tissue with abundant matrix.
conoid
greek konoeides = resembling a cone, cone shape
contralateral
(kon´´trua-lat´er-al) taking place or originating in a corresponding part on the opposite side of the body.
conus arteriosus
(see infundibulum)
conus medullaris
(kó nus med´´yuu-l=ar´is) the inferior, tapering portion of the spinal cord.
convolution
(kon-vuo-loo´shun) an elevation on the surface of a structure and an infolding of the tissue upon itself.
coracoid
adjective, greek korax = a crow, and eidos = shape or form, hence, like a crow's beak
cornea
(kor´ne-ua) the transparent, convex, anterior portion of the outer layer of the eyeball.
coronal plane
(kor´uo-nal, kuo-ro´nal) a plane that divides the body into anterior and posterior portions; also called a frontal plane.
coronary circulation
(kor´uo-nar´´e) the arterial and venous blood circulation to the wall of the heart.
coronary sinus
a large venous channel on the posterior surface of the heart into which the cardiac veins drain.
corpora quadrigemina
(kor´por-ua kwad´´ru1-jem´u1-na) four superior lobes of the midbrain concerned with visual and auditory functions.
corpus callosum
(kor´pus kua-lo´sum) latin corpus=body, callosum-hard; a large tract of hard white matter within the brain that connects the right and left cerebral hemispheres.
corpuscle of touch
(kor´pus'l) a touch sensory receptor found in the papillary layer of the dermis of the skin; also called meissner's corpuscle.
cortex
(kor´teks) 1.the outer layer of an internal organ or body structure, as of the kidney or adrenal gland. 2. the convoluted layer of gray matter that covers the surface of each cerebral hemisphere.
cortical
latin = bark like; the hard outer bone of a long bone. (see cancellous)
costal cartilage
(kos´tal) the cartilage that connects the ribs to the sternum.
cranial
(kra´ne-al) pertaining to the cranium.
cranial nerves
one of 12 pairs of nerves that arise from the brain.
cranium
(kra´ne-um) the bones of the skull that enclose or support the brain and the organs of sight, hearing, and balance.
crenation
(kru1-na´shun) a notched or scalloped appearance of the red blood cell membrane caused by the osmotic loss of water from these cells.
crest
a thickened ridge of bone for the attachment of muscle.
cricoid cartilage
(kri´koid) greek krikos = ring, and eidos = shape; a ring-shaped cartilage that forms the inferior portion of the larynx.
cribriform
adjective, latin cribrum = sieve, hence, sieve-like
crista
(kris´tua) latin = crest; a crest, such as the crista galli that extends superiorly from the cribriform plate of the ethmoid bone.
crista terminalis
marks the junction between the two embyological parts of the right atruim of the heart. at its upper end is the sinoatrial node.
cryptorchidism
(krip-tor´ku1-diz´´em) a developmental defect in which one or both testes fail to descend into the scrotum and, instead, remain in the body cavity.
cubital
(kyoo´bu1-tal) latin cubitus = elbow; the cubital fossa is the anterior aspect of the elbow joint.
cyanosis
(si´ua-no´sis) a bluish discoloration of the skin or mucous membranes due to excessive concentration of deoxyhemoglobin; indicates inadequate oxygen concentration in the blood.
cystic duct
(sis´tik dukt) the tube that transports bile from the gallbladder to the common bile duct.
cytology
(si-tol´uo-je) the science dealing with the study of cells.
deciduous
(du1-sij´oo-us) Pertaining to something shed or cast off in a particular sequence. Deciduous teeth are shed and replaced by permanent teeth during development.
decussation
(dek´´uh-sa´shun) A crossing of nerve fibres from one side of the CNS to the other.
deep
Far, or further, from the surface (see superficial)
defecation
(def´´ue-ka´shun) The elimination of faeces from the rectum through the anal canal and out the anus.
deglutition
(de´´gloo-tish´un) The act of swallowing.
dendrite
(den´dr=1t) A nerve cell process that transmits impulses toward a neuron cell body.
dentin
(den´tin) The main substance of a tooth, covered by enamel over the crown of the tooth and by cementum on the root.
dentition
(den-tish´un) The number, arrangement, and shape of teeth.
dependent
in a relaxed state, lying down (see erect, supine)
dermal papilla
(pua-pil´ua) A projection of the dermis into the epidermis.
dermatomes
the strip of skin supplied by one spinal nerve (sensory) (see myotomes)
dermis
(der´mis) The second, or deep, layer of skin beneath the epidermis.
descending colon
The segment of the large intestine that descends on the left side from the level of the spleen to the level of the left iliac crest.
diapedesis
(di´´ua-pue-de´sis) The migration of white blood cells through the endothelial walls of blood capillaries into the surrounding connective tissues.
diaphragm
(di´ua-fram) A sheetlike dome of muscle and connective tissue that separates the thoracic and abdominal cavities.
diaphysis
(di-af´u1-sis) The shaft of a long bone.
diarrhoea
(di´´ua-re´ua) Abnormal frequency of defecation accompanied by abnormal liquidity of the feces.
diarthrosis
(di´´ar-thro´sis) A type of functionally classified joint in which the articulating bones are freely movable; also called a synovial joint.
diastole
(di-as´tuo-le) The sequence of the cardiac cycle during which a heart chamber wall is relaxed.
diencephalon
(di´´en-sef´ua-lon) A major region of the brain that includes the third ventricle, thalamus, hypothalamus, and pituitary gland.
digestion
(The process by which larger molecules of food substance are broken down mechanically and chemically into smaller molecules that can be absorbed.
diploe
(dip´lo-e) The spongy layer of bone positioned between the inner and outer layers of compact bone.
distal
(dis´tal) Further away from the midline or origin; the opposite of proximal.
dorsal
(dor´sal) Pertaining to the back or posterior portion of a body part; the opposite of ventral; also called posterior.
dorsal root ganglion
(See posterior root ganglion)
dorsiflexion
(dor´´su1-flek´shun) Movement at the ankle as the dorsum of the foot is elevated.
dorsum
Latin = back. During development, the lower limb rotates medially so that extensors are at the front, flexors at the back, the knee points forward (not backward like the elbow) and the dorsum of the foot is at the front, not the back.
ductus arteriosus
(duk´tus ar-tir´´e-o´sus) The blood vessel that connects the pulmonary trunk and the aorta in a fetus.
ductus deferens
(def´er-enz) pl. ductus deferentia A tube that carries spermatozoa from the epididymis to the ejaculatory duct; also called the vas deferens or seminal duct.
ductus venosus
(ven-o´sus) A fetal blood vessel that connects the umbilical vein and the inferior vena cava.
duodenum
(doo´´uo-de´num, doo-od´ue-num) The first portion of the small intestine that leads from the pylorus of the stomach to the jejunum.
dura mater
(door´ua ma´ter) The outermost meninx.
eccrine gland
(ek´rin) A sweat gland that functions in thermoregulation.
ectoderm
(ek´tuo-derm) The outermost of the three primary germ layers of an embryo.
ectopic
(ek-top´ik) Greek ek = out, and topos = place, hence out of place
edema
(ue-de´mua) An excessive accumulation of fluid in the body tissues.
effector
(ue-fek´tor) An organ, such as a gland or muscle, that responds to a motor stimulation.
efferent
(ef´er-ent) Conveying away from the center of an organ or structure.
efferent arteriole
(ar-tir´e-=ol) An arteriole of the renal vascular system that conducts blood away from the glomerulus of a nephron.
efferent ductules
(duk´toolz) A series of coiled tubules through which spermatozoa are transported from the rete testis to the epididymis.
efferent neuron
(noor´on) See motor neuron.
elastic fibres
(ue-las´tik) Protein strands that are found in certain connective tissue that have contractile properties.
elbow
The synovial joint between the brachium and the antebrachium.
embryology
(em´´bre-ol´uo-je) The study of prenatal development from conception through the eighth week in utero.
emphysema
(em´´fu1-se´mua, em´´fu1-ze´mua) A lung disease in which the alveoli are destroyed and the remaining alveoli become larger. It results in decreased vital capacity and increased airway resistance.
emulsification
(ue-mul´´su1-fu1-ka´shun) The process of producing an emulsion or fine suspension; in the small intestine, fat globules are emulsified by the detergent action of bile.
enamel
(ue-nam´el) The outer dense substance covering the crown of a tooth.
endocardium
(en´´do-kar´de-um) The endothelial lining of the heart chambers and valves.
endochondral bone
(en´´duo-kon´dral) Denoting bones that develop as hyaline cartilage models first and that are then ossified.
endocrine
(en´duo-krin) secretion by a cell into its blood vessels (see exocrine).
endoderm
(en´duo-derm) The innermost of the three primary germ layers of an embryo.
endogenous
(en-doj´ue-nus) Denoting a product or process arising from within the body (as opposed to exogenous products or influences from external sources).
endolymph
(en´duo-limf) A fluid within the membranous labyrinth and cochlear duct of the inner ear that aids in the conduction of vibrations involved in hearing and the maintenance of equilibrium.
endometrium
(en´´do-me´tre-um) The inner lining of the uterus.
endoplasmic reticulum
(en-do-plaz´mik rue-tik´yuu-lum) A cytoplasmic organelle composed of a network of canals running through the cytoplasm of a cell.
endothelium
(en´´do-the´le-um) The layer of epithelial tissue that forms the thin inner lining of blood vessels and heart chambers.
enteric
(en-ter´ik) The term referring to the small intestine.
epicardium
(ep´´u1-kar´de-um) A thin, outer layer of the heart; also called the visceral pericardium.
epicondyle
(ep´´u1-kon´d1=l) A projection of bone above a condyle.
epidermis
(ep´´u1-der´mis) The outermost layer of the skin, composed of several stratified squamous epithelial layers.
epididymis
(ep´´u1-did´u1-mis) A highly coiled tube located along the posterior border of the testis. It stores spermatozoa and transports them from the seminiferous tubules of the testis to the ductus deferens.
epidural space
(ep´´u1-door´al) A space between the spinal dura mater and the bone of the vertebral canal. (epidural anasthetic - a liquid anastetic is injected into the extra(epi)dural space. insertion of hollow needle through the skin of the back and the ligamentum flavum. The needle is not advanced further as for a lumbar puncture)
epigastric region
Greek epi = upon, and gaster = belly, hence, the upper median zone of the abdomen (see hypochondriac, umbilical, lumbar, inguinal and hypogastric)
epiglottis
(ep´´u1-glot´is) A leaf like structure positioned on top of the larynx. It covers the glottis during swallowing.
epiphyseal plate
(ep´´u1-fiz´e-al) A hyaline cartilaginous layer located between the epiphysis and diaphysis of a long bone. It functions as a longitudinal growing region.
epiphysis
(ue-pif´u1-sis) The end segment of a long bone, separated from the diaphysis early in life by an epiphyseal plate but later becoming part of the larger bone.
epiploic
adjective, Greek epiploon = a net, which the greater omentum resembles with fat entangled in it. Synonymous with omental, mesenteric and ligamentous.
episiotomy
(ue-pe´´ze-ot´uo-me) An incision of the perineum at the end of the second stage of labor to facilitate delivery and to avoid tearing the perineum.
epithelial tissue
(ep´´u1-the´le-al) One of the four basic tissue types; the type of tissue that covers or lines all exposed body surfaces.
eponychium
(ep´´uo-nik´e-um) The thin layer of stratum corneum of the epidermis of the skin that overlaps and protects the lunula of the nail.
erect
Standing upright (see dependent, supine, prone)
erythrocyte
(ue-rith´ruo-s1=t) A red blood cell.
eustachian canal
(yoo-sta´ke-an) See auditory tube.
eversion
(ue-ver´zhun) A movement of the foot in which the sole is turned outward (laterally).
exocrine
(ek´suo-krin) A cell or group of cells that secretes its product to an epithelial surface, directly or through ducts.
expiration
(ek´´spu1-ra´shun) The process of expelling air from the lungs through breathing out; also called exhalation.
extension
(ek-sten´shun) A movement that increases the angle between parts of a joint. (Usually straighten)
extensor
(A muscle that, upon contraction, increases the angle of a joint.
external
(superficial) Located on or toward the surface.
external acoustic meatus
(ua-koo´stik me-a´tus) An opening through the temporal bone that connects with the tympanum and the middle-ear chamber and through which sound vibrations pass; also called the external auditory meatus.
exteroceptors
(ek´´stue-ro-sep´torz) Sensory receptors that are sensitive to changes in the external environment (as opposed to interoceptors).
extraocular muscles
(ek´´strua-ok´yuu-lar) The muscles that insert into the sclera of the eye and that act to change the position of the eye in its orbit (as opposed to the intraocular muscles, such as those of the iris and ciliary body within the eye).
extrinsic
(eks-trin´sik) Pertaining to an outside or external origin.
face
Two meanings; 1.The anterior aspect of the head not supporting or covering the brain. 2.The exposed surface of a structure.
facet
(fas´et) A small, smooth surface of a bone where articulation occurs.
faeces
(fe´s=ez) Material expelled from the GI tract during defecation, composed of undigested food residue, bacteria, and secretions; also called stool.
falciform ligament
(fal´su1-form lig´ua-ment) An extension of parietal peritoneum that separates the right and left lobes of the liver.
fallopian tube
(fua-lo´pe-an) See uterine tube.
false vocal cords
The supporting folds of tissue for the true vocal cords within the larynx.
falx cerebelli
(falks ser´´ue-bel´e) A fold of the dura mater anchored to the occipital bone. It projects inward between the cerebellar hemispheres.
falx cerebri
(ser´ue-bre) A fold of dura mater anchored to the crista galli of the ethmoid bone. It extends between the right and left cerebral hemispheres.
fascia
(fash´e-ua) Two meanings:1. Superficial fascia:Loose connective and fatty tissue, of variable thickness (prevertebral) 2. Deep fascia:A tough sheet of fibrous tissue binding the skin to underlying muscles or supporting and separating muscles. (clavipectoral)
fascia lata
deep fascia of the thigh
fasciculus
(fua-sik´yuu-lus) A small bundle of muscle or nerve fibers.
fauces
(faw´s=ez) Latin = throat, the passageway between the mouth and the pharynx.
fibrin
(fi´brin) The insoluble protein formed from fibrinogen by the enzymatic action of thrombin during the process of blood clot formation.
fibrous joint
(fi´brus) A type of articulation bound by fibrous connective tissue that allows little or no movement (a synarthrosis). (see syndesmosis, suture, gomphosis)
fibular
Can be used to mean lateral side of the leg (see tibial, peroneal)
filiform papillae
(fil´u1-form pua-pil´e) Numerous small projections over the entire surface of the tongue in which taste buds are absent.
filum terminale
(fi´lum ter-mu1-nal´e) A fibrous, threadlike continuation of the pia mater, extending inferiorly from the terminal end of the spinal cord to the coccyx.
fimbriae
(fim´bre-e) Latin = a fringe, fringe like extensions. (e.g. open end of the uterine tube)
fissure
(fish´ur) A groove or narrow cleft that separates two parts, such as the cerebral hemispheres of the brain.
flagellum
(flua-jel´um) A whip like structure that provides motility for sperm.
flexion
(flek´shun) A movement that decreases the angle between parts of a joint.
flexor
(flek´sor) A muscle that decreases the angle of a joint when it contracts.
foetus
(fe´tus) A prenatal human after 8 weeks of development.
fontanel
(fon´´tua-nel´) A membranous-covered region on the skull of a fetus or baby where ossification has not yet occurred; commonly called a soft spot.
foot
The terminal portion of the lower extremity, consisting of the tarsal bones, metatarsal bones, and phalanges.
foramen
(fuo-ra´men), pl. foramina An opening in an anatomical structure, usually in a bone, for the passage of a blood vessel or a nerve.
foramen ovale
(o-val´e) An opening through the interatrial septum of the fetal heart.
forearm
The portion of the upper extremity between the elbow and the wrist; also called the antebrachium. (see arm, brachium)
fornix
(for´niks) Latin = arch:1.A recess around the cervix of the uterus where it protrudes into the vagina. 2.A tract within the brain connecting the hippocampus with the mammillary bodies.
fossa
(fos´ua) A depressed area, usually on a bone.
fourth ventricle
(ven´tru1-k'l) A cavity within the brain, between the cerebellum and the medulla oblongata and the pons, containing cerebrospinal fluid.
fovea centralis
(fo´ve-ua sen-tra´ lis) Latin = a pit (usually smaller than a fossa), a depression on the macula lutea of the eye, where only cones are located; the area of keenest vision.
frenulum
(fren´yuu-lum) Latin = bridle or curb:a membranous structure that serves to anchor and limit the movement of a body part.
frontal
Two meanings 1.Pertaining to the region of the forehead. 2. A plane through the body, dividing the body into anterior and posterior portions; also called the coronal plane.
fundus
Latin = bottom or base. (But note that the fundus of the stomach and uterus are at the top, and the fundus of the eye and of the bladder are posterior!).
fungiform papillae
(fun´ju1-form pua-pil´e) Flattened, mushroom-shaped projections interspersed over the surface of the tongue in which taste buds are present.
gallbladder
A pouchlike organ attached to the underside of the liver in which bile secreted by the liver is stored and concentrated.
ganglion
(gang´gle-on) Greek = swelling, an aggregation of nerve cell bodies occurring outside the central nervous system.
gastrointestinal tract
(GI tract) (gas´´tro-in-tes´tu1-nal) The portion of the digestive tract that includes the stomach and the small and large intestines.
gigantism
(ji-gan´tiz´´em) Abnormal body growth as a result of the excessive secretion of growth hormone.
gingiva
(jin´ju1-vua) The fleshy covering over the mandible and maxilla through which the teeth protrude within the mouth; also called the gum.
gland
An organ that produces a specific substance or secretion.
glans penis
(glanz pe´nis) The enlarged, sensitive, distal end of the penis.
gliding joint
A type of synovial joint in which the articular surfaces are flat, permitting only side-to-side and back-and-forth movements.
glomerular capsule
(glo-mer´yuu-lar) The double-walled proximal portion of a renal tubule that encloses the glomerulus of a nephron; also called Bowman's capsule.
glottis
(glot´is) A slitlike opening into the larynx, positioned between the true vocal cords.
glycogenolysis
(gli´´kuo-jue-nol´u1-sis) The hydrolysis of glycogen to glucose 1-phosphate, which can be converted to glucose 6-phosphate, which then may be oxidized via glycolysis or (in the liver) converted to free glucose.
goblet cell
A unicellular mucus-secreting gland that is associated with columnar epithelia; also called a mucous cell.
Golgi tendon organ
A sensory receptor found near the junction of tendons and muscles.
gomphosis
Fibrous joint between teeth and jaw.
gonad
(go´nad) A reproductive organ, testis or ovary, that produces gametes and sex hormones.
Graves' disease
A hyperthyroid condition believed to be caused by excessive stimulation of the thyroid gland by autoantibodies; it is associated with exophthalmos (bulging eyes), high pulse rate, high metabolic rate, and other symptoms of hyperthyroidism.
grey matter
The region of the central nervous system composed of nonmyelinated nerve tissue.
greater omentum
(o-men´tum) A double-layered peritoneal membrane that originates on the greater curvature of the stomach. It hangs inferiorly like an apron over the contents of the abdominal cavity.
gross anatomy
The branch of anatomy concerned with structures of the body that can be studied without a microscope.
gustatory
(gus´tua-tor´´e) Pertaining to the sense of taste.
gut
(The GI tract or a portion thereof; generally used in reference to the embryonic digestive tube, consisting of the foregut, midgut, and hindgut.
gyrus
(ji´rus) Greek gyros = circle, a convoluted elevation or ridge.
hair
A threadlike appendage of the epidermis consisting of keratinized dead cells that have been pushed up from a dividing basal layer.
hair cells
Specialized receptor nerve endings for detecting sensations, such as in the spiral organ (organ of Corti).
hair follicle
(fol´lu1-k'l) A tubular depression in the dermis of the skin in which a hair develops.
hallucis
Latin hallex = great toe (hallucis = of the great toe).
hand
The terminal portion of the upper extremity, containing the carpal bones, metacarpal bones, and phalanges.
hard palate
(pal´it) The bony partition between the oral and nasal cavities, formed by the maxillae and palatine bones and lined by mucous membrane.
haustra
(haws´trua) Sacculations or pouches of the colon.
haversian canal
(hua-ver´shan) See central canal.
haversian system
See osteon.
head
(The uppermost portion of a human that contains the brain and major sense organs.
heart
A four-chambered, muscular pumping organ positioned in the thoracic cavity, slightly to the left of midline.
heart murmur
An auscultatory sound of cardiac or vascular origin, usually caused by an abnormal flow of blood in the heart as a result of structural defects of the valves or septum.
hepatic duct
(hue-pat´ik) A duct formed from the fusion of several bile ducts that drain bile from the liver. The hepatic duct merges with the cystic duct from the gallbladder to form the common bile duct.
hepatic portal circulation
The return of venous blood from the digestive organs and spleen through a capillary network within the liver before draining into the heart.
hepatopancreatic ampulla
(hep´´ua-to-pan´´kre-at´ik) A small, elevated area within the duodenum where the combined pancreatic and common bile duct empties; also called the ampulla of Vater.
Hering-Breuer reflex
A reflex in which distension of the lungs stimulates stretch receptors, which in turn act to inhibit further distension of the lungs.
hermaphrodite
(her-maf´ruo-d=1t) An organism having both testes and ovaries.
hiatal hernia
(hi-a´tal her´ne-ua) A protrusion of an abdominal structure through the esophageal hiatus of the diaphragm into the thoracic cavity.
hiatus
Latin = a gap, an opening or fissure; a foramen.
hilum
(hi´lum) A concave or depressed area where vessels or nerves enter or exit an organ; also called hilus.
hinge joint
A type of synovial articulation characterized by a convex surface of one bone fitting into a concave surface of another such that movement is confined to one plane, as in the elbow or interphalangeal joint.
histology
(hu1-stol´uo-je) Microscopic anatomy of the structure and function of tissues.
horizontal
(transverse, axial) plane A directional plane that divides the body, organ, or appendage into superior and inferior or proximal and distal portions.
hormone
(hor´m=on) A chemical substance produced in an endocrine gland and secreted into the bloodstream to cause an effect in a specific target organ.
hyaline cartilage
(hi´ua-l=1n) A cartilage with a homogeneous matrix. It is the most common type, occurring at the articular ends of bones, in the trachea, and within the nose. Most of the bones in the body are formed from hyaline cartilage.
hyaline membrane disease
A disease affecting premature infants who lack pulmonary surfactant, it is characterized by collapse of the alveoli (atelectasis) and pulmonary edema; also called respiratory distress syndrome.
hydrophilic
(hi´´druo-fil´ik) Denoting a substance that readily absorbs water; literally, "water loving."
hydrophobic
(hi´´druo-fo´bik) Denoting a substance that repels, and that is repelled by, water; "water fearing."
hymen
(hi´men) A developmental remnant (vestige) of membranous tissue that partially covers the vaginal opening.
hyperextension
(hi´´per-ek-sten´shun) Extension beyond the normal anatomical position.
hyperopia
(hi´´per-o´pe-ua) A refractive disorder in which rays of light are brought to a focus behind the retina as a result of the eyeball being too short; also called longsightedness.
hyperplasia
(hi´´per-pla´zha) An increase in organ size due to an increase in cell numbers as a result of mitotic cell division (in contrast to hypertrophy).
hypertension
(hi´´per-ten´shun) Elevated or excessive blood pressure.
hypertrophy
(hi´´per´truo-fe) Growth of an organ due to an increase in the size of its cells (in contrast to hyperplasia).
hyperventilation
(hi´´per-ven´´tu1-la´shun) A high rate and depth of breathing that results in a decrease in the blood carbon dioxide concentration to below normal.
hypochondriac region
An abdominal region (see umbilical, epigastric, lumbar, inguinal and hypogastric)
hypodermis
(hi´´puo-der´mis) A layer of fat beneath the dermis of the skin.
hyponychium
(hi´´puo-nik´e-um) A thickened, supportive layer of stratum corneum at the distal end of a digit under the free edge of the nail.
hypothalamus
(hi´´po-thal´ua-mus) A portion of the forebrain within the diencephalon that lies below the thalamus, where it functions as an autonomic nerve center and regulates the pituitary gland.
ileocecal valve
(il´´e-uo-se´kal) a modification of the mucosa at the junction of the small and large intestine that forms a one-way passage and prevents the backflow of food materials.
ileum
(il´e-um) the terminal portion of the small intestine between the jejunum and cecum.
iliac fossa
groin area (see inguinal region)
ilium
the components of the hip bone, the ilium, ischium and pubis, meet in the centre of the acetabulum, the three parts fusing at about 16 yrs of age.
incus
(ing´kus) the middle of three auditory ossicles within the middle-ear chamber; commonly called the anvil.
inferior vena cava
(ve´nua ka´vua) a large systemic vein that collects blood from the body regions inferior to the level of the heart and returns it to the right atrium.
infundibulum
(in´´fun-dib´yuu-lum) latin = funnel, the stalk that attaches the pituitary gland to the hypothalamus of the brain.
ingestion
(in-jes´chun) the process of taking food or liquid into the body by way of the oral cavity.
inguinal region
(ing´gwu1-nal) pertaining to the groin region. (see iliac fossa)
inguinal canal
the circular passageway in the abdominal wall through which a testis descends into the scrotum.
insertion
the more movable attachment of a muscle, usually more distal. (see attachment)
inspiration
(in´´spu1-ra´shun) the act of breathing air into the alveoli of the lungs; also called inhalation.
insula
(in´suu-lua) a deep, paired cerebral lobe.
integument
(in-teg´yoo-ment) the skin; the largest organ of the body.
intercellular substance
(in´´ter-sel´yuu-lar) the matrix or material between cells that largely determines tissue types.
intercostal
space between ribs.
internal (deep)
toward the center, away from the surface of the body.
internal ear
the innermost portion or chamber of the ear, containing the cochlea and the vestibular organs.
interosseous membrane
a fiberous membrane attaching bones in a fiberous joint of variable flexibility e.g. intermediate radioulnar joint, inferior tibiofibular joint (see syndesmoses)
intervertebral disc
(in´´ter-ver´tue-bral) a pad of fibrocartilage located between the bodies of adjacent vertebrae. (see annulus fibrosus, neucleus pulposus)
intestinal crypt
a simple tubular digestive gland opening onto the surface of the intestinal mucosa that secretes digestive enzymes; also called the crypt of lieberkühn.
intramembranous ossification
(see membranous bone.)
intrapleural space
(in´´trua-ploor´al) an actual or potential space between the visceral pleural membrane covering the lungs and the somatic pleural membrane lining the thoracic wall.
intrinsic
(in-trin´zik) situated within or pertaining to internal origin.
invaginate
to fold inwards or sheathe.
inversion
(in-ver´zhun) a movement of the foot in which the sole is turned inward.
in vitro
(in ve´tro) occurring outside the body, in a test tube or other artificial environment.
in vivo
(in ve´vo) occurring within the body.
ipsilateral
(ip´´su1-lat´er-al) on the same side (as opposed to contralateral).
iris
(i´ris) the pigmented portion of the vascular tunic of the eye that surrounds the pupil and regulates its diameter.
ischemia
(u1-ske´me-ua) a rate of blood flow to an organ that is inadequate to supply sufficient oxygen and maintain aerobic respiration in that organ.
ischium
the components of the hip bone, the ilium, ischium and pubis, meet in the centre of the acetabulum, the three parts fusing at about 16 yrs of age
islets of Langerhans
(i´letz of lang´er-hanz) See pancreatic islets.
isthmus
(is´mus) Greek isthmos = a narrow passage, a narrow neck or portion of tissue connecting two structures.
jaundice
(jawn´dis) A condition characterized by high blood bilirubin levels and staining of the tissues with bilirubin, which imparts a yellow color to the skin and mucous membranes.
jejunum
(jue-joo´num) The middle portion of the small intestine, located between the duodenum and the ileum.
joint capsule
(The fibrous tissue that encloses the joint cavity of a synovial joint.
jugular
adjective, Latin jugulum = neck
keratin
(ker´ua-tin) An insoluble protein present in the epidermis and in epidermal derivatives, such as hair and nails.
kidney
(kid´ne) One of a pair of organs of the urinary system that contains nephrons and that filters wastes from the blood in the formation of urine.
kinesiology
(ku1-ne´´se-ol´uo-je) The study of body movement.
knee
(A region in the lower extremity between the thigh and the leg that contains a synovial hinge joint.
kyphosis
Greek kyphos = bent or bowed forward, dorsal convexity of the spine (see lordosis, scoliosis)
labial frenulum
(la´be-al fren´yuu-lum) A longitudinal fold of mucous membrane that attaches the lips to the gum along the midline of both the upper and lower lip.
labia majora
(la´be-ua mua-jor´ua), sing. labium majus A portion of the external genitalia of a female consisting of two longitudinal folds of skin extending downward and backward from the mons pubis.
labia minora
(mu1-nor´ua), sing. labium minus Two small folds of skin, devoid of hair and sweat glands, lying between the labia major of the external genitalia of a female.
labyrinth
(lab´u1-rinth) An intricate structure consisting of interconnecting passages (e.g., the bony and membranous labyrinths of the inner ear.
lacrimal canaliculus
(lak´ru1-mal kan´´ua-lik´yuu-lus) A drainage duct for tears, located at the medial corner of an eyelid. It conveys the tears medially into the nasolacrimal sac.
lacrimal gland
(A tear-secreting gland, located on the superior lateral portion of the eyeball underneath the upper eyelid.
lactation
(lak-ta´shun) The production and secretion of milk by the mammary glands.
lacteal
(lak´te-al) A small lymphatic duct associated with a villus of the small intestine.
lacuna
(lua-kyoo´nua) A small, hollow chamber that houses an osteocyte in mature bone tissue or a chondrocyte in cartilage tissue.
lambdoidal suture
(lam´doid-al soo´chur) The immovable joint in the skull between the parietal bones and the occipital bone.
lamella
(lua-mel´ua) A concentric ring of matrix surrounding the central canal in an osteon of mature bone tissue.
lamellated corpuscle
(lam´ue-la-ted) A sensory receptor for pressure, found in tendons, around joints, and in visceral organs; also called a pacinian corpuscle.
lamina
(lam´u1-nua) A thin plate of bone that extends superiorly from the body of a vertebra to form either side of the arch of a vertebra.
lanugo
(lau-noo´go) Short, silky fetal hair, which may be present for a short time on a premature infant.
large intestine
The last major portion of the GI tract, consisting of the cecum, colon, rectum, and anal canal.
laryngopharynx
(lua-ring´´go-far´ingks) The inferior or lower portion of the pharynx in contact with the larynx. 686
larynx
(lar´ingks) The structure located between the pharynx and trachea that houses the vocal cords; commonly called the voice box.
lateral
(lat´er-al) Pertaining to the side; farther from the midplane.
lateral ventricle
(ven´tru1-k'l) A cavity within the cerebral hemisphere of the brain that is filled with cerebrospinal fluid.
leg
(The portion of the lower extremity between the knee and ankle (see thigh)
lens
(lenz) A transparent refractive organ of the eye positioned posterior to the pupil and iris.
lesion
(le´zhun) A wounded or damaged area.
lesser omentum
(o-men´tum) A peritoneal fold of tissue extending from the lesser curvature of the stomach to the liver.
ligament
(lig´ua-ment) A tough cord or fibrous band of connective tissue that binds bone to bone to strengthen and provide flexibility to a joint. It also may support viscera.
ligamentous
(not to be confused with other uses of ligament) synonymous with omental, epiploic and mesenteric.
ligamentum flavum
connecting adjacent laminae. (see lamina, lumbar puncture)
limbic system
(lim´bik) A portion of the brain concerned with emotions and autonomic activity.
limbus
Latin = a margin, edge, usually curved
linea alba
(lin´e-ua al´bua) A vertical fibrous band extending down the anterior medial portion of the abdominal wall.
lingual frenulum
(ling´gwal fren´yuu-lum) A longitudinal fold of mucous membrane that attaches the tongue to the floor of the oral cavity.
lithotomy position
lying on the back, with the lower limbs elevated and the feet in stirrups.
liver
(A large visceral organ inferior to the diaphragm in the right hypochondriac region. The liver detoxifies the blood and modifies the blood plasma concentration of glucose, triglycerides, ketone bodies, and proteins.
lower extremity
(A lower appendage, including the hip, thigh, knee, leg, and foot.
lumbar
(lum´bar) Pertaining to the region of the loins.
lumbar plexus
(plek´sus) A network of nerves formed by the anterior branches of spinal nerves L1 through L4.
lumbar puncture
insertion of hollow needle through the skin of the back, the ligamentum flavum, and the dura mater. In the Adult the needle should be inserted between the vertebtal laminae of L3/4. in a child one or two intervertebral spaces below. (see epidural)
lumbar region
A region of the abdomen (see hypochondriac, epigastric, umbilical, inguinal and hypogastric)
lumen
(loo´men) The space within a tubular structure through which a substance passes.
lung
One of the two major organs of respiration positioned within the thoracic cavity on either side of the mediastinum.
lunula
(loo´nyoo-lua) The half-moon-shaped whitish area at the proximal portion of a nail.
Lymph
(limf) A clear, plasma like fluid that flows through lymphatic vessels.
lymphatic system
(lim-fat´ik) The lymphatic vessels and lymph nodes.
lymph node
A small, ovoid mass of reticular tissue located along the course of lymph vessels.
macula lutea
(mak´yuu-lua loo´te-ua) A yellowish depression in the retina of the eye that contains the fovea centralis, the area of keenest vision.
malignant
threatening to life; virulent. Of a tumor, cancerous, tending to metastasize.
malleus
(mal´e-us) The first of three auditory ossicles that attaches to the tympanum; commonly called the hammer.
mammary gland
(mam´er-e) The gland of the female breast responsible for lactation and nourishment of the young.
marrow
(mar´o) The soft connective tissue found within the inner cavity of certain bones that produces red blood cells.
mast cell
A type of connective tissue cell that produces and secretes histamine and heparin and promotes local inflammation.
mastication
(mas´´tu1-ka´shun) The chewing of food.
Matrix
(ma´triks) The intercellular substance of a tissue.
McBurney?s point
A point within the Right Lumbar region of the abdomen surface marking the base of the appendix. Specifically, one third the way along a line drawn from the right ASIS to the umbilicus.
meatus
(me-a´tus) Latin = passage; adjective - meatal. A passageway or opening into a structure.
mechanoreceptor
(mek´´ua-no-re-sep´tor) A sensory receptor that responds to a mechanical stimulus.
medial
(me´de-al) Toward or closer to the midplane of the body.
mediastinum
(me´´de-ua-sti´num) The partition in the center of the thorax between the two pleural cavities.
medulla
(mue-dul´ua) The center portion of an organ.
medulla oblongata
(ob´´long-gua´tua) A portion of the brain stem located between the spinal cord and the pons.
medullary
(med´l-er´´e) (Latin=marrow) The hollow core of the diaphysis of a long bone in which marrow is found.
Meissner's corpuscle
(m=1s´nerz) See corpuscle of touch.
melanin
(mel´ua-nin) A dark pigment found within the epidermis or epidermal derivatives of the skin.
melanocyte
(mel´ua-no-s=1t) A specialized melanin-producing cell found in the deepest layer of the epidermis.
melanoma
(mel´´ua-no´mua) A dark, malignant tumor of the skin that frequently forms in moles.
membranous bone
(mem´brua-nus) Bone that forms from membranous connective tissue rather than from cartilage.
membranous labyrinth
(lab´u1-rinth) A system of communicating sacs and ducts within the bony labyrinth of the inner ear that includes the cochlea and vestibular apparatus. It is filled with endolymph and surrounded by perilymph and bone.
Ménière's disease
(m=an-yarz´) Deafness, tinnitus, and vertigo resulting from a disorder of the labyrinth.
meninges
(mue-nin´j=ez), sing. meninx. A group of three fibrous membranes covering the central nervous system, composed of the dura mater, arachnoid mater, and pia mater.
menisci
(mue-nis´ke) Wedge-shaped fibrocartilages in certain synovial joints.
menopause
(men´uo-pawz) The period marked by the cessation of menstrual periods in the human female.
menstrual cycle
(men´stroo-al) The rhythmic female reproductive cycle, characterized by changes in hormone levels and physical changes in the uterine lining.
menstruation
(men´´stroo-a´shun) The discharge of blood and tissue from the uterus at the end of the menstrual cycle.
mesencephalic aqueduct
(mez´´en-sue-fal´ik ak´wue-dukt) The channel that connects the third and fourth ventricles of the brain; also called the aqueduct of Sylvius.
mesencephalon
(mes´´en-sef´ua-lon) The midbrain, which contains the corpora quadrigemina and the cerebral peduncles.
mesenchyme
(mez´en-k=1m) An embryonic connective tissue that can migrate, and from which all connective tissues arise.
mesenteric
synonymous with omental, epiploic and ligamentous.
mesenteric patches
(mes´´en-ter´ik) Clusters of lymph nodes on the walls of the small intestine; also called Peyer's patches.
mesentery
(mes´en-ter´´e) A fold of peritoneal membrane that attaches an abdominal organ to the abdominal wall.
mesoderm
(mes´uo-derm) The middle one of the three primary germ layers.
mesothelium
(mes´´uo-the´lium) A simple squamous epithelial tissue that lines body cavities and covers visceral organs; also called serosa.
mesovarium
(mes´´uo-va´re-um) The peritoneal fold that attaches an ovary to the broad ligament of the uterus.
metacarpus
(met´´ua-kar´pus) The region of the hand between the wrist and the phalanges, including the five metacarpal bones that support the palm of the hand.
metastasis
(mue-tas´tua-sis) The spread of a disease from one organ or body part to another.
metatarsus
(met´´ua-tar´sus) The region of the foot between the ankle and the phalanges that includes the five metatarsal bones.
metencephalon
(met´´en-sef´ua-lon) The most superior portion of the hindbrain that contains the cerebellum and the pons.
microvilli
(mi´´kro-vil´i) Microscopic hairlike projections of cell membranes on certain epithelial cells.
micturition
(mik´´tuu-rish´un) The process of voiding urine; also called urination.
midbrain
The portion of the brain between the pons and the forebrain.
midclavicular lines
Longitudinal lines drawn from the mid-point of the clavicle to the mid-point of the inguinal ligament.
middle ear
The middle of the three portions of the ear that contains the three auditory ossicles.
midsagittal plane
(mid-saj´u1-tal) A plane that divides the body into equal right and left halves; also called the median plane or midplane.
mitochondria
(mi´´tuo-kon´dre-ua), sing. mitochondrion Cytoplasmic organelles that serve as sites for the production of most of the cellular energy; the so-called powerhouses of the cell.
mitral valve
(mi´tral) The left atrioventricular heart valve; also called the bicuspid valve.
mixed nerve
A nerve that contains both motor and sensory nerve fibers.
mons pubis
(monz pyoo´bis) A fatty tissue pad covering the symphysis pubis and covered by pubic hair in the female.
motor area
A region of the cerebral cortex from which motor impulses to muscles or glands originate.
motor nerve
A nerve composed of motor nerve fibers.
motor neuron
(noor´on) A nerve cell that conducts action potentials away from the central nervous system and innervates effector organs (muscle and glands). It forms the anterior roots of the spinal nerves; also called an efferent neuron.
motor unit
A single motor neuron and the muscle fibers it innervates.
mucosa
(myoo-ko´sua) A mucous membrane that lines cavities and tracts opening to the exterior.
mucous cell
(myoo´kus) See goblet cell.
mucous membrane
(A thin sheet consisting of layers of visceral organs that include the lining epithelium, submucosal connective tissue, and(in some cases) a thin layer of smooth muscle (the muscularis mucosa).
Murphy?s point
Surface marking for the Gall Bladder. Where the midclavicular line and the transpyloric plane cross on the right side.
muscle
(mus´el) A major type of tissue adapted to contract. The three kinds of muscle are cardiac, smooth, and skeletal.
muscle group
Muscles rarely act in isolation. They are formed as part of a group usually supplied with the same nerve and within one fascial (see fascia) compartment, and it is the group as a whole that acts. So not only need you not worry about remembering which end of a muscle is the origin and which the insertion (see attachments), in many cases you need not worry about individual muscles - only muscle groups.
muscularis
(mus´´kyuu-la´ris) A muscular layer or tunic of an organ, composed of smooth muscle tissue.
mydriasis
dilation of the pupils
myelencephalon
(mi´´ue-len-sef´ua-lon) The posterior portion of the hindbrain that contains the medulla oblongata.
myelin
(mi´ue-lin) A lipoprotein material that forms a sheathlike covering around nerve fibers.
myelin sheath
A sheath surrounding axons formed by successive wrappings of a neuroglial cell membrane. Myelin sheaths are formed by neurolemmocytes in the peripheral nervous system and by oligodendrocytes within the central nervous system.
myenteric plexus
(mi´´en-ter´ik plek´sus) A network of sympathetic and parasympathetic nerve fibers located in the muscularis tunic of the small intestine; also called the plexus of Auerbach.
myocardial infarction
(mi´´uo-kar´de-al in-fark´shun) An area of necrotic tissue in the myocardium that is filled in by scar (connective) tissue.
myocardium
(mi´´uo-kar´de-um) The cardiac muscle layer of the heart.
myology
(mi-ol´uo-je) The science or study of muscle structure and function.
myometrium
(mi´´o-me´tre-um) The layer or tunic of smooth muscle within the uterine wall.
myopia
(mi-o´pe-ua) A visual defect in which objects may be seen distinctly only when very close to the eyes; also called shortsightedness.
myotomes
the skeletal muscle/muscle group supplied by one spinal cord segment (motor) (see dermatomes)
nail
A hardened, keratinized plate that develops from the epidermis and forms a protective covering on the surface of the distal phalanges of fingers and toes.
nasal cavity
(na´zal) A mucosa-lined space above the oral cavity, divided by a nasal septum. It is the first chamber of the respiratory system.
nasal concha
(kong´kua) A scroll-like bone extending medially from the lateral wall of the nasal cavity; also called a turbinate bone.
nasal septum
(sep´tum) A bony and cartilaginous partition that separates the nasal cavity into two portions.
nasopharynx
(na´´zo-far´ingks) The first or uppermost chamber of the pharynx, positioned posterior to the nasal cavity and extending down to the soft palate.
neck
Two meanings:1.Any constricted portion, such as the neck of an organ. 2.The cervical region of the body between the head and thorax.
necrosis
(nue-kro´sis) Cellular death or tissue death due to disease or trauma.
negative feedback
A mechanism in the body for maintaining a state of internal constancy, or homeostasis; effectors are activated by changes in the internal environment, and the actions of the effectors serve to counteract these changes and maintain a state of balance.
neonatal
(ne´´o-na´tal) Newborn, the stage of life from birth to the end of 4 weeks.
neoplasm
(ne´uo-plazm) A new, abnormal growth of tissue, as in a tumor.
nephron
(nef´ron) The functional unit of the kidney, consisting of a glomerulus, convoluted tubules, and a nephron loop.
nerve
A bundle of nerve fibers outside the central nervous system.
neurilemma
(noor´´u1-lem´ua) A thin, membranous covering surrounding the myelin sheath of a nerve fiber.
neurofibril node
A gap in the myelin sheath of a nerve fiber; also called a node of Ranvier.
neuroglia
(noo-rog´le-ua) Specialized supportive cells of the central nervous system.
neurohypophysis
(noor´´o-hi-pof´u1-sis) The posterior lobe of the pituitary gland derived from the brain. Its major secretions include antidiuretic hormone (ADH), also called vasopressin, and oxytocin, produced in the hypothalamus.
neurolemmocyte
(noor´´uo-lem´uo-s=1t) A specialized neuroglia cell that surrounds an axon fiber of a peripheral nerve and forms the neurilemmal sheath; also called a Schwann cell.
neuron
(noor´on) The structural and functional unit of the nervous system, composed of a cell body, dendrites, and an axon; also called a nerve cell.
nexus
(nek´sus) A bond between members of a group; the type of bonds present in single-unit smooth muscles.
nipple
(A dark pigmented, rounded projection at the tip of the breast.
node of Ranvier
(ran´ve-a) See neurofibril node.
notochord
(no´tuo-kord) A flexible rod of tissue that extends the length of the back of an embryo.
nucleus
(noo´kle-us) A spheroid body within a cell that contains the genetic factors of the cell.
nucleus pulposus
(pul-po´sus) Fibrocartilaginous soft core of an intervertebral disc (see annulus fibrosus)
nystagmus
(nu1-stag´mus) Involuntary oscillary movements of the eye.
obese
(o-b=es´) Excessively fat.
olfactory
(ol-fak´tuo-re) Pertaining to the sense of smell.
olfactory bulb
(An aggregation of sensory neurons of an olfactory nerve, lying inferior to the frontal lobe of the cerebrum on either lateral side of the crista galli of the ethmoid bone.
olfactory tract
(The olfactory sensory tract of axons that conveys impulses from the olfactory bulb to the olfactory portion of the cerebral cortex.
oligodendrocyte
(ol´´u1-go-den´druo-s=1t) A type of neuroglial cell concerned with the formation of the myelin of nerve fibers within the central nervous system.
omental
synonymous with mesenteric, epiploic and ligamentous.
omentum
Latin = apron; adjective - omental
oncology
(on-kol´uo-je) The study of tumors.
optic
(op´tik) Pertaining to the eye.
optic chiasma
(ki-az´mua) An X-shaped structure on the inferior aspect of the brain, anterior to the pituitary gland, where there is a partial crossing over of fibers in the optic nerves; also called the optic chiasm.
optic disc
(A small region of the retina where the fibers of the ganglion neurons exit from the eyeball to form the optic nerve; also called the blind spot.
optic tract
A bundle of sensory axons located between the optic chiasma and the thalamus that functions to convey visual impulses from the photoreceptors within the eye.
oral
Latin oris = a mouth. Pertaining to the mouth.
ora serrata
The jagged peripheral margin of the retina.
organ
A structure consisting of two or more tissues that performs a specific function.
organelle
(or´´gua-nel´) A minute living structure of a cell with a specific function.
organism
An individual living creature.
organ of Corti
(kor´te) See spiral organ.
orifice
(or´u1-fis) An opening into a body cavity or tube.
origin
The place of muscle attachment-usually the more stationary point or the proximal bone; opposite the insertion.
oropharynx
(o´´ro-far´ingks) The second portion of the pharynx, located posterior to the oral cavity and extending from the soft palate to the hyoid bone.
osmolality
(oz´´muo-lal´u1-te) A measure of the total concentration of a solution; the number of moles of solute per kilogram of solvent.
osmosis
(oz-mo´sis) The passage of solvent (water) from a more dilute to a more concentrated solution through a membrane that is more permeable to water than to the solute.
osseous tissue
(os´e-us) Greek osteon = bone.
ossicle
(os´u1-kul) One of the three bones of the middle ear; also called the auditory ossicle.
ossification
(os´´u1-fu1-ka´shun) The process of bone tissue formation.
osteoblast
(os´te-uo-blast) A bone-forming cell.
osteoclast
(os´te-uo-klast) A cell that causes erosion and resorption of bone tissue.
osteocyte
(os´te-uo-s=1t) A mature bone cell.
osteology
(os´´te-ol´uo-je) The study of the structure and function of bone and the entire skeleton.
osteomalacia
(os´´te-o-mua-la´shua) Softening of bones due to a deficiency of vitamin D and calcium.
osteon
(os´te-on) A group of osteocytes and concentric lamellae surrounding a central canal, constituting the basic unit of structure in osseous tissue; also called a haversian system.
osteoporosis
(os´´te-o-puo-ro´sis) Demineralization of bone, seen most commonly in postmenopausal women and patients who are inactive or paralyzed. It may be accompanied by pain, loss of stature, and other deformities and fractures.
otoliths
(o´tuo-liths) Small, hardened particles of calcium carbonate in the saccule and utricle of the inner ear, associated with the receptors of equilibrium; also called statoconia.
outer ear
The outer portion of the ear, consisting of the auricle and the external auditory canal.
oval window
An oval opening in the bony wall between the middle and inner ear, into which the footplate of the stapes fits; also called the vestibular window.
ovarian ligament
(lig´ua-ment) A cordlike connective tissue that attaches the ovary to the uterus.
ovary
(o´vua-re) The female gonad in which ova and certain sexual hormones are produced.
oviduct
(o´vu1-dukt) The tube that transports ova from the ovary to the uterus; also called the uterine tube or fallopian tube.
palate
(pal´at) The roof of the oral cavity.
palatine
(pal´ua-t=1n) Pertaining to the palate.
palmar
(pal´mar) Pertaining to the palm of the hand.
palpation
To examine by the sense of touch.
palpebra
(pal´pue-brua) An eyelid.
pancreas
(pan´kre-as) A mixed organ in the abdominal cavity that secretes pancreatic juices into the GI tract and insulin and glucagon into the blood.
pancreatic duct
(pan´´kre-at´ik) A drainage tube that carries pancreatic juice from the pancreas into the duodenum of the hepatopancreatic ampulla.
pancreatic islets
A cluster of cells within the pancreas that forms the endocrine portion and secretes insulin and glucagon; also called islets of Langerhans.
papillae
(pua-pil´e) Small, nipplelike projections.
papillary muscle
(pap´u1-ler´´e) Muscular projections from the ventricular walls of the heart to which the chordea tendineae are attached.
paranasal sinus
(par´´ua-na´zal si´nus) An air chamber lined with a mucous membrane that communicates with the nasal cavity.
parasympathetic
(par´´ua-sim´´pua-thet´ik) Pertaining to the division of the autonomic nervous system concerned with activities that, in general, inhibit or oppose the physiological effects of the sympathetic nervous system (eg relaxes us for gut tube activity (salivation, gastric activity, peristalsis, sphincter relaxation), it constricts the pupils, slows the heart, and it has important reproductive functions.) (see sympathetic)
parathyroids
(par´´ua-thi´roidz) Small endocrine glands embedded on the posterior surface of the thyroid glands that are concerned with calcium metabolism.
parietal
(pua-ri´ue-tal) Pertaining to a wall of an organ or cavity.
parietal pleura
(ploor´ua) The thin serous membrane attached to the thoracic walls of the pleural cavity.
parotid gland
(pua-rot´id) One of the paired salivary glands located on the side of the face over the masseter muscle just anterior to the ear and connected to the oral cavity through a salivary duct.
parturition
(par´´tyoo-rish´un) The process of giving birth; childbirth.
pathogen
(path´uo-jen) Any disease-producing microorganism or substance.
pectoral
(pek´tuo-ral) Pertaining to the chest region.
pectoral girdle
The portion of the skeleton that supports the upper extremities.
pedicle
(ped´u1-k'l) The portion of a vertebra that connects and attaches the lamina to the body.
pelvic
(pel´vik) Pertaining to the pelvis.
pelvic girdle
The portion of the skeleton to which the lower extremities are attached.
pelvis
(pel´vis) the term pelvis can mean the bony pelvis (a basin like bony structure formed by the sacrum and ossa coxae), the pelvic part of the abdominal cavity or the renal pelvis
penis
(pe´nis) (latin=tail) The male organ of copulation, used to introduce sperm into the female vagina and through which urine passes during urination.
pennate
(pen´=at) Pertaining to a skeletal muscle fibre arrangement in which the fibres are attached to tendinous slips in a featherlike pattern.
pepsin
(pep´sin) The protein-digesting enzyme secreted in gastric juice.
peptic ulcer
(pep´tik ul´ser) An injury to the mucosa of the esophagus, stomach, or small intestine due to the action of acidic gastric juice.
perforating canal
A minute duct through compact bone by which blood vessels and nerves penetrate to the central canal of an osteon; also called Volkmann's canal.
pericardium
(per´´u1-kar´de-um) A protective serous membrane that surrounds the heart.
perichondrium
(per´´u1-kon´dre-um) A toughened connective sheet that covers some kinds of cartilage.
perikaryon
(per´´u1-kar´e-on) The cell body of a neuron.
perilymph
(per´u1-limf) A fluid of the inner ear that provides a liquid-conducting medium for the vibrations involved in hearing and the maintenance of equilibrium.
perimysium
(per´´u1-mis´e-um) Fascia (connective tissue) surrounding a bundle of muscle fibers.
perineum
(per´´u1-ne´um) The floor of the pelvis, which is the region between the anus and the symphysis pubis. It is the region that contains the external genitalia.
perineurium
(per´´u1-noor´e-um) Connective tissue surrounding a bundle of nerve fibers.
periodontal membrane
(per´´e-uo-don´tal) A fibrous connective tissue lining the dental alveoli.
periosteum
(per´´e-os´te-um) A fibrous connective tissue covering the outer surface of bone.
peripheral nervous system
(pue-rif´er-al) The nerves and ganglia of the nervous system that lie outside of the brain and spinal cord. (PNS) This includes both the crainial nerves arising from the brain (12 pairs) and the spinal nerves arising from the spinal cord (31 pairs, usually) (see central nervous system)
peristalsis
(per´´u1-stal´sis) Rhythmic contractions of smooth muscle in the walls of various tubular organs by which the contents are forced onward.
peritoneal cavity
Strictly speaking nothing is in the peritoneal cavity except a thin layer of peritoneal fluid. But it is used synonymously with the abdominal pelvic cavity.
peritoneum
(per´´1u-tuo-ne´um) The serous membrane that lines the abdominal cavity and covers the abdominal visceral organs.
peroneal
(greek) can be used to mean lateral in the leg, going out of fashion (see fibular, tibial)
phalanx
(fa´langks), pl. phalanges A bone of a finger or toe.
pharynx
(far´ingks) The organ of the digestive system and respiratory system located at the back of the oral and nasal cavities that extends to the larynx anteriorly and to the esophagus posteriorly; also called the throat.
photoreceptor
(fo´´to-re-sep´tor) A sensory nerve ending that responds to the stimulation of light.
physiology
(fiz´´e-ol´uo-je) The science that deals with the study of body functions.
pia mater
(pi´ua ma´ter) The innermost meninx that is in direct contact with the brain and spinal cord.
pineal gland
(pin´e-al) A small cone-shaped gland located in the roof of the third ventricle.
pinna
(pin´ua) The outer, fleshy portion of the external ear; also called the auricle.
pinocytosis
(pin´´uo-si-to´sis) Cell drinking; invagination of the cell membrane forming narrow channels that pinch off into vacuoles. This allows for cellular intake of extracellular fluid and dissolved molecules.
pituitary gland
(pu1-too´u1-ter-e) A small, pea-shaped endocrine gland situated on the interior surface of the diencephalonic region of the brain, consisting of anterior and posterior lobes; also called the hypophysis.
pivot joint
(piv´ut) A synovial joint in which the rounded head of one bone articulates with the depressed cup of another to permit a rotational type of movement only.
placenta
(plua-sen´tua) The organ of metabolic exchange between the mother and the fetus.
plantar
(plan´tar) Pertaining to the sole of the foot.
plantarflexion
A movement at the ankle joint. Pointing toes down to the ground (flexion) (see dorsiflexion)
plasma
(plaz´mua) The fluid, extracellular portion of circulating blood.
platelets
(pl=at-letz) Small fragments of specific bone marrow cells that function in blood coagulation; also called thrombocytes.
pleural
(ploor´al) Pertaining to the serous membranes associated with the lungs.
pleural cavity
The potential space between the visceral pleura and parietal pleura.
pleural membranes
Serous membranes that surround the lungs and provide protection and compartmentalization.
plexus
(plek´sus) A network of interlaced nerves or vessels.
plexus of Auerbach
(ow´er-bak) See myenteric plexus.
plexus of Meissner
(m=1s´ner) See submucosal plexus.
plicae circulares
(pli´ce sur-kyuu-lar´=ez) Deep folds within the wall of the small intestine that increase the absorptive surface area.
pneumotaxic area
(noo´´muo-tak´sik) The region of the respiratory control center located in the pons of the brain.
pollicus
Latin pollex = thumb; hence of the thumb
polyuria
(pol´´e-yoor´e-ua) Excretion of an excessively large volume of urine in a given period.
pons
(ponz) The portion of the brain stem just above the medulla oblongata and anterior to the cerebellum.
popliteal
(pop´´lu1-te´al, pop-lit´e-al) Pertaining to the concave region on the posterior aspect of the knee.
posterior
(pos-t=er´e-or) Toward the back; also called dorsal.
posterior pituitary
(pu1-too´u1-ter-e) See neurohypophysis.
posterior root
An aggregation of sensory neuron fibres lying between a spinal nerve and the posterolateral aspect of the spinal cord; also called the dorsal root or sensory root.
posterior root ganglion
(gang´gle-on) A cluster of cell bodies of sensory neurons located along the posterior root of a spinal nerve.
postnatal
(p=ost-na´tal) After birth.
pregnancy
A condition in which a female is carrying a developing offspring within the body.
prenatal
(pre-na´tal) Pertaining to the period of offspring development during pregnancy; before birth.
prepuce
(pre´pyoos) A fold of loose, retractable skin covering the glans of the penis or clitoris; also called the foreskin.
process
Latin = going forwards, used to indicate growing out, i.e., an outgrowth, usually of bone, e.g., the zygomatic process of the temporal bone.
pronation
(pro-na´shun) A rotational movement of the forearm in which the palm of the hand is turned posteriorly.
proprioceptor
(pro´´pre-o-sep´tor) A sensory nerve ending that responds to changes in tension in a muscle or tendon.
prostate
(pros´t=at) A walnut-shaped gland surrounding the male urethra just below the urinary bladder that secretes an additive to seminal fluid during ejaculation.
prosthesis
(pros-the´sis) An artificial device to replace a diseased or worn body part.
protoplasm
(pro´tuo-plaz´´em) A general term for the colloidal complex of protein that constitutes the living material of a cell. It includes cytoplasm and nucleoplasm.
protraction
(pro-trak´shun) The movement of a body part, such as the mandible, forward on a plane parallel with the ground; the opposite of retraction.
proximal
(prok´-su1-mal) Closer to the midplane of the body or to the origin of an appendage; the opposite of distal.
pseudohermaphrodite
(soo´´duo-her-maf´ruo-d1=t) An individual with some of the physical characteristics of both sexes, but who lacks functioning gonads of both sexes; a true hermaphrodite has both testes and ovaries.
puberty
(pyoo´ber-te) The period of development in which the reproductive organs become functional.
pubis
the components of the hip bone, the ilium, ischium and pubis, meet in the centre of the acetabulum, the three parts fusing at about 16 yrs of age
pulmonary
(pul´muo-ner´´e) Pertaining to the lungs.
pulmonary circulation
The system of blood vessels from the right ventricle of the heart to the lungs that transports deoxygenated blood and returns oxygenated blood from the lungs to the left atrium of the heart.
pulp cavity
A cavity within the center of a tooth that contains blood vessels, nerves, and lymphatics.
pupil
The opening through the iris that permits light to enter the posterior cavity of the eyeball and be refracted by the lens through the vitreous chamber.
Purkinje fibers
(pur-kin´je) See conduction myofibers.
pyloric sphincter
(pi-lor´ik sfingk´ter) A modification of the muscularis tunic between the stomach and the duodenum that functions to regulate the food material leaving the stomach.
pylorus
Greek = gate-keeper; hence, the part of the pyloric canal containing the sphincter, which guards the opening into the duodenum; adjective - pyloric
pyramid
(pir´ua-mid) Any of several structures that have a pyramidal shape (e.g., the renal pyramids in the kidney and the medullary pyramids on the anterior surface of the brain).
quadriceps
Latin quadri = four, and caput = head; hence, a 4-headed muscle
radial
This is the preferred term for the lateral side of forearm and hand (see ulnar)
ramus
(ra´mus) A branch of a bone, artery, or nerve.
raphe
(ra´fe) A ridge or a seamlike structure between two similar parts of a body organ, as in the scrotum.
receptor
(re-sep´tor) A sense organ or a specialized distal end of a sensory neuron that receives stimuli from the environment.
rectum
(rek´tum) The terminal portion of the GI tract, between the sigmoid colon and the anal canal.
red marrow
(mar´o) A tissue that forms blood cells, located in the medullary cavity of certain bones.
red nucleus
(noo´kle-us) An aggregation of grey matter of a reddish colour located in the upper portion of the midbrain. It sends fibers to certain brain tracts.
reflex
(re´fleks) A rapid involuntary response to a stimulus.
regional anatomy
The division of anatomy concerned with structural arrangement in specific areas of the body, such as the head, neck, thorax, or abdomen.
renal
(re´nal) Pertaining to the kidney.
renal corpuscle
(kor´pus'l) The portion of the nephron consisting of the glomerulus and a glomerular capsule; also called the malpighian corpuscle.
renal cortex
The outer portion of the kidney, primarily vascular.
renal medulla
(mue-dul´ua) The inner portion of the kidney, including the renal pyramids and renal columns.
renal pelvis
The inner cavity of the kidney formed by the expanded ureter and into which the calyces open.
renal pyramid
A triangular structure within the renal medulla composed of nephron loops and the collecting ducts.
respiration
(res´´pu1-ra´shun) The exchange of gases between the external environment and the cells of an organism.
respiratory center
The structure or portion of the brain stem that regulates the depth and rate of breathing.
respiratory distress syndrome
A lung disease of the newborn, most frequently occurring in premature infants, that is caused by abnormally high alveolar surface tension as a result of a deficiency in lung surfactant; also called hyaline membrane disease.
respiratory membrane
A thin, moistened membrane within the lungs, composed of an alveolar portion and a capillary portion, through which gaseous exchange occurs.
rete testis
(re´te tes´tis) A network of ducts in the center of the testis associated with the production of spermatozoa.
reticular formation
(rue-tik´yuu-lar) A network of nervous tissue fibers in the brain stem that arouses the higher brain centers.
retina
(ret´u1-nua) The principal portion of the internal tunic of the eyeball that contains the photoreceptors.
retinaculum
Latin = a tether; hence, a thickened band of deep fascia which retains tendons or the patella
retraction
(re-trak´shun) The movement of a body part, such as the mandible, backward on a plane parallel with the ground; the opposite of protraction.
retroflexion
Latin retro = backwards, and flexion = bent; hence, the position of being bent backwards, applied to the angulation of the body of the uterus on the cervix (see anteflexion)
retroperitoneal
(ret´´ro-per´´u1-tuo-ne´al) Positioned behind the parietal peritoneum.
retroversion
Latin retro = backwards, and version = turned; hence, the position of being turned backwards, applied to the angulation of the cervix uteri on the vagina. (see anteversion)
rhythmicity area
(rith-mis´u1-te) A portion of the respiratory control center located in the medulla oblongata that controls inspiratory and expiratory phases.
ribosome
(ri´bo-s=om) A cytoplasmic organelle composed of protein and RNA in which protein synthesis occurs.
rickets
(rik´ets) A condition caused by a deficiency of vitamin D and associated with an interference of the normal ossification of bone.
right lymphatic duct
(lim-fat´ik) A major vessel of the lymphatic system that drains lymph from the upper right portion of the body into the right subclavian vein.
rigor mortis
(rig´or mor´tis) The stiffening of a dead body due to the depletion of ATP and the production of rigor complexes between actin and myosin in muscles.
rod
A photoreceptor in the retina of the eye that is specialized for colorless, dim-light vision.
root canal
The hollow, tubular extension of the pulp cavity into the root of the tooth that contains vessels and nerves.
rotation
(ro-ta´shun) The movement of a bone around its own longitudinal axis.
round window
A round, membrane-covered opening between the middle and inner ear, directly below the oval window; also called the cochlear window.
rugae
(roo´je) Latin = a wrinkle. The folds or ridges of the mucosa of an organ.
saccadic eye movements
(sua-kad´ik) Very rapid eye movements that occur constantly and that change the focus on the retina from one point to another.
saccule
(sak´yool) A sac like cavity in the membranous labyrinth inside the vestibule of the inner ear that contains a vestibular organ for equilibrium.
sacral
(sa´kral) Pertaining to the sacrum.
sacral plexus
(plek´sus) A network of nerve fibers that arises from spinal nerves L4 through S3. Nerves arising from the sacral plexus merge with those from the lumbar plexus to form the lumbosacral plexus and supply the lower extremity.
saddle joint
A synovial joint in which the articular surfaces of both bones are concave in one plane and convex or saddle shaped, in the other plane, such as in the distal carpometacarpal joint of the thumb.
sagittal plane
(saj´u1-tal) A vertical plane, running parallel to the midsagittal plane, that divides the body into unequal right and left portions.
salivary gland
(sal´u1-ver-e) An accessory digestive gland that secretes saliva into the oral cavity.
scala tympani
(ska´lau tim´pua-ne) The lower channel of the cochlea that is filled with perilymph.
scala vestibuli
(vue-stib´yuu-le) The upper channel of the cochlea that is filled with perilymph.
sclera
(skler´ua) The outer white layer of fibrous connective tissue that forms the protective covering of the eyeball.
scleral venous sinus
(ve´nus) A circular venous drainage for the aqueous humor from the anterior chamber; located at the junction of the sclera and the cornea; also called the canal of Schlemm.
scoliosis
(see lordosis, kyphosis)
scrotum
(skro´tum) A pouch of skin that contains the testes and their accessory organs.
sebaceous gland
(sue-ba´shus) An exocrine gland of the skin that secretes sebum.
sebum
(se´bum) An oily, waterproofing secretion of the sebaceous glands.
semen
(se´men) The thick, whitish secretion of the reproductive organs of the male, consisting of spermatozoa and additives from the prostate and seminal vesicles.
semicircular canals
(Tubule channels within the inner ear that contain receptors for equilibrium.
semilunar valve
(sem´´e-loo´nar) Crescent- or half-moon-shaped heart valves positioned at the entrances to the aorta and the pulmonary trunk.
seminal vesicles
(sem´u1-nal ves´u1-k'lz) A pair of accessory male reproductive organs lying posterior and inferior to the urinary bladder that secrete additives to spermatozoa into the ejaculatory ducts.
seminiferous tubules
(sem´´u1-nif´er-us too´byoolz) Numerous small ducts in the testes, where spermatozoa are produced.
semipermeable membrane
(sem´´e-per´me-ua-b'l) A membrane with pores of a size that permits the passage of solvent and some solute molecules while restricting the passage of other solute molecules.
senescence
(sue-nes´ens) The process of aging.
sensory area
A region of the cerebral cortex that receives and interprets sensory nerve impulses.
sensory neuron
(noor´on) A nerve cell that conducts an impulse from a receptor organ to the central nervous system; also called an afferent neuron.
septum
(sep´tum) A membranous or fleshy wall dividing two cavities.
serous membrane
(ser´us) An epithelial and connective tissue membrane that lines body cavities and covers visceral organs within these cavities; also called serosa.
serum
(ser´um) Blood plasma with the clotting elements removed.
sesamoid bone
(ses´ua-moid) A membranous bone formed in a tendon in response to joint stress (e.g., the patella).
shock
As it relates to the cardiovascular system, this term refers to a rapid, uncontrolled fall in blood pressure, which in some cases becomes irreversible and leads to death.
shoulder
The region of the body where the humerus articulates with the scapula.
sigmoid colon
(sig´moid ko´lon) The S-shaped portion of the large intestine between the descending colon and the rectum.
sinoatrial node
(sin´´no-a´tre-al) A mass of specialized cardiac tissue in the wall of the right atrium that initiates the cardiac cycle; the SA node; also called the pacemaker.
sinus
(si´nus) A cavity or hollow space within a body organ, such as a bone.
sinusoid
(si´nuu-soid) A small, blood-filled space in certain organs, such as the spleen or liver.
skeletal muscle
A specialized type of multinucleated muscle tissue that occurs in bundles, has crossbands of proteins, and contracts in either a voluntary or involuntary fashion.
small intestine
The portion of the GI tract between the stomach and the cecum whose function is the absorption of food nutrients.
smooth muscle
A specialized type of nonstriated muscle tissue composed of fusiform, single-nucleated fibers. It contracts in an involuntary, rhythmic fashion within the walls of visceral organs.
soft palate
(pal´at) The fleshy, posterior portion of the roof of the mouth, from the palatine bones to the uvula.
somatic
(so-mat´ik) Pertaining to the nonvisceral parts of the body.
sounds of Korotkoff
(kuo-rot´kof) The sounds heard when pressure measurements are taken. These sounds are produced by the turbulent flow of blood through an artery that has been partially constricted by a pressure cuff.
spermatic cord
(sper-mat´ik) The structure of the male reproductive system composed of the ductus deferens, spermatic vessels, nerves, cremaster muscle, and connective tissue. The spermatic cord extends from a testis to the inguinal ring.
sphincter
(sfingk´ter) A circular muscle that functions to constrict a body opening or the lumen of a tubular structure.
sphincter of ampulla
The muscular constriction at the opening of the common bile and pancreatic ducts; also called the sphincter of Oddi.
sphincter of Oddi
(o´de) See sphincter of ampulla.
sphygmomanometer
(sfig´´mo-mua-nom´u1-ter) A manometer (pressure transducer) used to measure the blood pressure.
spinal cord
(spi´nal) The portion of the central nervous system that extends downward from the brain stem through the vertebral canal.
spinal ganglion
A cluster of nerve cell bodies on the posterior root of a spinal nerve.
spinal nerve
(One of the 31 pairs of nerves that arise from the spinal cord.
spinous process
(spi´nus) A sharp projection of bone or a ridge of bone, such as on the scapula.
spiral organ
The functional unit of hearing, consisting of a basilar membrane supporting receptor hair cells and a tectorial membrane within the endolymph of the cochlear duct; also known as the organ of Corti.
spleen
(spl=en) A large, blood-filled, glandular organ located in the upper left quadrant of the abdomen and attached by mesenteries to the stomach.
spongy bone
(Bone tissue with a lattice like structure; also called cancellous bone.
squamous
(skwa´mus) Flat or scalelike.
stapes
(sta´p=ez) The innermost of the auditory ossicles that fits against the oval window of the inner ear; also called the stirrup.
stomach
A pouchlike digestive organ located between the esophagus and the duodenum.
stratified
(strat´u1-f=1d) Arranged in layers, or strata.
stratum basale
(stra´tum bua-sua´le) The deepest epidermal layer, where mitotic activity occurs.
stratum corneum
(kor´ne-um) The outer, cornified layer of the epidermis of the skin.
stroma
(stro´mua) A connective tissue framework in an organ, gland, or other tissue.
subarachnoid space
(sub´´ua-rak´noid) The space within the meninges between the arachnoid mater and pia mater, where cerebrospinal fluid flows.
subcostal plane
vertebral level L2/3. This is the plane marking the lowest point of the ribcage
subcutaneous
Beneath the skin
subdural space
a potential space (i.e. not normally present) between the closely adjacent arachnoid and dura mater. (see meninges, subarachnoid space)
sublingual gland
(sub-ling´gwal) One of the three pairs of salivary glands. It is located below the tongue and its duct opens to the side of the lingual frenulum.
submandibular gland
(sub´´man-dib´yuu-lar) One of the three pairs of salivary glands. It is located below the mandible and its duct opens to the side of the lingual frenulum.
submucosa
(sub´´myoo-ko´sa) A layer of supportive connective tissue that underlies a mucous membrane.
submucosal plexus
(sub´´myoo-k=os´al plek´sus) A network of sympathetic and parasympathetic nerve fibers located in the submucosa tunic of the small intestine; also called the plexus of Meissner.
sulcus
(sul´kus) A shallow impression or groove.
superficial
(soo´´per-fish´al) Toward or near the surface.
superficial fascia
(fash´e-ua) A binding layer of connective tissue between the dermis of the skin and the underlying muscle.
superior
(Toward the upper part of a structure or toward the head; also called cephalic.
superior vena cava
A large systemic vein that collects blood from regions of the body superior to the heart and returns it to the right atrium.
supination
(soo´´pu1-na´shun) Rotation of the arm so that the palm is directed forward or anteriorly; the opposite of pronation.
surface anatomy
The division of anatomy concerned with the structures that can be identified from the outside of the body.
suspensory ligament
(suu-spen´suo-re) Two meanings - 1.A portion of the peritoneum that extends laterally from the surface of the ovary to the wall of the pelvic cavity. 2. A ligament that supports an organ or body part, such as that supporting the lens of the eye.
sustentaculum tali
(latin = support of the talus) a process on the medial aspect of the calcaneum, palpable inferior to the head of the talus.
sutural bone
(soo´chur-al) A small bone positioned within a suture of certain cranial bones; also called a wormian bone.
suture
(soo´chur) A type of fibrous joint found between bones of the skull.
sweat gland
A skin gland that secretes a fluid substance for evaporative cooling.
sympathetic
(sim´´pua-thet´ik) Pertaining to the division of the autonomic nervous system concerned with activities that, in general, arouse the body for physical activity, it is active when we are alert, fearful or stressed, dilating the pupils (see mydriasis) and speeding the heart. It is also important in temparature regulation (goosebumps, blushing/blanching and sweating); also called the thoracolumbar division. (see parasympathetic)
symphysis
(sim´fu1-sis) A type of cartilaginous joint characterized by a fibrocartilaginous pad between the articulating bones, which provides slight movement.
symphysis pubis
(pyoo´bis) A slightly movable joint located anteriorly between the two pubic bones of the pelvic girdle.
synapse
(sin´aps) A minute space between the axon terminal of a presynaptic neuron and a dendrite of a postsynaptic neuron.
synarthrosis
(sin´´ar-thro´sis) A fibrous joint, such as a syndesmosis or a suture.
synchondrosis
(sin´´kon-dro´sis) A cartilaginous joint in which the articulating bones are separated by hyaline cartilage.
syndesmosis
(sin´´des-mo´sis) A type of fibrous joint in which two bones are united by an interosseous ligament.
synergist
(sin´er-jist) A muscle that assists the action of the prime mover.
synovial cavity
(su1-no´ve-al) A space between the two bones of a synovial joint, filled with synovial fluid.
synovial joint
A freely movable joint in which there is a synovial cavity between the articulating bones; also called a diarthrotic joint.
synovial membrane
The inner membrane of a synovial capsule that secretes synovial fluid into the joint cavity.
synovium
Specialised connective tissue that secretes synovial fluid to lubricate the articular surfaces.
system
A group of body organs that function together.
systemic
(sis-tem´ik) Relating to the entire organism rather than to individual parts.
systemic anatomy
The division of anatomy concerned with the structure and function of the various systems.
systemic circulation
The portion of the circulatory system concerned with blood flow from the left ventricle of the heart to the entire body and back to the heart via the right atrium (in contrast to the pulmonary system, which involves the lungs).
systole
(sis´tuo-le) The muscular contraction of a heart chamber during the cardiac cycle.
tachycardia
(tak´´u1-kar´de-ua) An excessively rapid heart rate, usually in excess of 100 beats per minute (in contrast to bradycardia, in which the heart rate is very slow).
tactile
(tak´til) Pertaining to the sense of touch.
taeniae coli
(te´ne-e ko´li) The three longitudinal bands of muscle in the wall of the large intestine.
tarsus
(tar´sus) The region of the foot containing the seven tarsal bones.
taste bud
An organ containing the chemocreceptors associated with the sense of taste.
tectorial membrane
(tek-to´re-al) A gelatinous membrane positioned over the hair cells of the spiral organ in the cochlea.
telencephalon
(tel´´en-sef´ua-lon) The anterior portion of the forebrain, constituting the cerebral hemispheres and related parts.
tendo calcaneous
(ten´do kal-ka´ne-us) The tendon that attaches the calf muscles to the calcaneous bone; also called the Achilles tendon.
tendon
(ten´dun) A band of dense regular connective tissue that attaches muscle to bone.
tendon sheath
A covering of synovial membrane surrounding certain tendons.
tenosynovitis
Inflammation of a tendon sheath
tentorium cerebelli
(ten-to´re-um ser´´ue-bel´e) An extension of dura mater that forms a partition between the cerebral hemispheres and the cerebellum and covers the cerebellum.
teratogen
(tue-rat´uo-jen) Any agent or factor that causes a physical defect in a developing embryo or fetus.
testis
(tes´tis) The primary reproductive organ of a male that produces spermatozoa and male sex hormones.
tetanus
(tet´n-us) A smooth contraction of a muscle (as opposed to muscle twitching).
thalamus
(thal´ua-mus) An oval mass of gray matter within the diencephalon that serves as a sensory relay center.
thebesian veins
small veins draining the myocardium directly into the chambers of the heart
thigh
The proximal portion of the lower extremity between the hip and the knee in which the femur is located (see leg)
third ventricle
(ven´tr1u-k'l) A narrow cavity between the right and left halves of the thalamus and between the lateral ventricles that contains cerebrospinal fluid.
thoracic
(tho-ras´ik) Pertaining to the chest region.
thoracic duct
The major lymphatic vessel of the body that drains lymph from the entire body, except for the upper right quadrant, and returns it to the left subclavian vein.
thorax
(thor´aks) The chest.
thrombocyte
(throm´buo-s=1t) A blood platelet formed from a fragmented megakaryocyte.
thrombus
(throm´bus) A blood clot produced by the formation of fibrin threads around a platelet plug.
thymus
(thi´mus) this is found in children anterior to the trachea, extending from the level of the cricoid cartilage down to the retrosternal area (A bilobed lymphoid organ). In the adult the thymic tissue is more or less confined to the retrosternal area
thyroid cartilage
(thi´roid kar´tu1-lij) The largest cartilage in the larynx that supports and protects the vocal cords; commonly called the Adam's apple.
tibial
can be used to mean medial in the leg (see fibular, peroneal)
tinnitus
(tu1-ni´tus) The spontaneous sensation of a ringing sound or other noise without sound stimuli.
tissue
An aggregation of similar cells and their binding intercellular substance, joined to perform a specific function.
tongue
A protrusible muscular organ on the floor of the oral cavity.
tonsil
(ton´sil) A node of lymphoid tissue located in the mucous membrane of the pharynx.
trabeculae
(trua-bek´yuu-le) A supporting framework of fibers crossing the substance of a structure, as in the lamellae of spongy bone. (see cancellous)
trachea
(tra´ke-ua) The airway leading from the larynx to the bronchi, composed of cartilaginous rings and a ciliated mucosal lining of the lumen; commonly called the windpipe.
tract
A bundle of nerve fibers within the central nervous system.
transpyloric plane
Vertebral level L1. This intersects the rib cage at the tip of the 9th costal cartilage. It is about half way between the xiphiod process and the umbilicus and it marks the position of several internal structures (e.g. pylorus. gall bladder, renal hila, origin of superior mesenteric artery)
transtubercular plane
Vertebral level L5. a line between the tubercles of the iliac crests
transverse colon
(trans-vers´ ko´lon) A portion of the large intestine that extends from right to left across the abdomen between the hepatic and splenic flexures.
transverse fissure
(fish´ur) The prominent cleft that horizontally separates the cerebrum from the cerebellum.
transverse plane
A plane that divides the body into superior and inferior portions; also called a horizontal, or cross-sectional, plane.
tricuspid valve
(tri-kus´pid) The heart valve located between the right atrium and the right ventricle. (see mitral)
trifurcation
A branching of a single vessel into three.
trigone
(tri´g=on) A triangular area in the urinary bladder between the openings of the ureters and the urethra.
trochanter
(tro-kan´ter) A broad, prominent process on the proximolateral portion of the femur.
trochlea
(trok´le-ua) A pulleylike anatomical structure (e.g., the medial surface of the distal end of the humerus that articulates with the ulna).
true vocal cords
Folds of the mucous membrane in the larynx that produce sound as they are pulled taut and vibrated.
trunk
The thorax and abdomen together.
tubercle
(too´ber-k'l) A small, elevated process on a bone.
tuberosity
(too´bu1-ros´u1-te) An elevation or protuberance on a bone.
tunica albuginea
(too´nu1-kua al´´byoo-jin´e-ua) A tough, fibrous tissue surrounding the testis.
tympanic membrane
(tim-pan´ik) The membranous eardrum positioned between the external and middle ear.
ulna
The medial and longer of the two bones in the forearm
ulnar
This is the preferred term for the medial side of the forearm and hand (see radial)
umbilical region
In the region of the umbilicus (see hypochondriac, epigastric, lumbar, inguinal and hypogastric)
umbilical cord
(um-bu1´lu1-kal) A cordlike structure containing the umbilical arteries and vein and connecting the fetus with the placenta.
umbilicus
(um-bu1-lu1-kus) The site where the umbilical cord was attached to the fetus; commonly called the navel.
unipolar neuron
(yoo´nu1-po-lar noor´on) A nerve cell that has a single nerve fiber extending from its cell body.
universal donor
A person with blood type O who is able to donate blood to people with other blood types in emergency blood transfusions.
universal recipient
A person with blood type AB who can receive blood of any type in emergency transfusions.
upper extremity
The appendage attached to the pectoral girdle, consisting of the shoulder, brachium, elbow, antebrachium, and hand.
urea
(yoo-re´ua) The chief nitrogenous waste product of protein catabolism in the urine, formed in the liver from amino acids.
uremia
(yoo-re´me-ua) The retention of urea and other products of protein catabolism as a result of inadequate kidney function.
ureter
(yoo-re´ter) A tube that transports urine from the kidney to the urinary bladder.
urethra
(yoo-re´thrua) A tube that transports urine from the urinary bladder to the outside of the body.
urinary bladder
(yoo´ru1-ner´´e) A distensible sac that stores urine, situated in the pelvic cavity posterior to the symphysis pubis.
uterine tube
(yoo´ter-in) The tube through which the ovum is transported to the uterus and the site of fertilization; also called the oviduct or fallopian tube.
uterus
(yoo´ter-us) A hollow, muscular organ in which a fetus develops. It is located within the female pelvis between the urinary bladder and the rectum; commonly called the womb.
utricle
(yoo´tru1-k'l) An enlarged portion of the membranous labyrinth, located within the vestibule of the inner ear.
uvula
(yoo´vyuu-lua) A fleshy, pendulous portion of the soft palate that blocks the nasopharynx during swallowing.
vacuole
(vak-yoo´=ol) A small space or cavity within the cytoplasm of a cell.
vagina
(vua-ji´nua) A tubular organ leading from the uterus to the vestibule of the female reproductive tract that receives the male penis during coitus.
vallate papillae
(val´=at pua-pil´e) The largest papillae on the surface of the tongue. They are arranged in an inverted V-shaped pattern at the posterior portion of the tongue.
vasectomy
(vua-sek´tuo-me, va-zek´tuo-me) Surgical removal of portions of the ductus deferentia to induce infertility.
vasoconstriction
(va´´zo-kon-strik´shun) Narrowing of the lumen of blood vessels due to contraction of the smooth muscles in their walls.
vasodilation
(va´´zo-di-la´shun) Widening of the lumen of blood vessels due to relaxation of the smooth muscles in their walls.
vasomotor center
(va´´zo-mo´tor) A cluster of nerve cell bodies in the medulla oblongata that controls the diameter of blood vessels. It is therefore important in regulating blood pressure.
vein
(v=an) A blood vessel that conveys blood toward the heart.
vena cava
(ve´nau ka´vua) One of two large vessels that return deoxygenated blood to the right atrium of the heart.
ventilation
(ven´´tu1-la´shun) Breathing; the process of moving air into and out of the lungs.
ventral
(ven´tral) Toward the front or facing surface; the opposite of dorsal; also called inferior.
ventricle
(ven´tru1-k'l) A cavity within an organ; especially those cavities in the brain that contain cerebrospinal fluid and those in the heart that contain blood to be pumped from the heart.
venule
(ven´yool) A small vessel that carries venous blood from capillaries to a vein.
vermis
(ver´mis) The coiled middle lobular structure that separates the two cerebellar hemispheres.
vertebral canal
(ver´tue-bral) The tubelike cavity extending through the vertebral column that contains the spinal cord; also called the spinal canal.
vertigo
(ver´tu1-go) A feeling of movement or loss of equilibrium.
vestibular window
See oval window.
vestibule
(ves´tu1-byool) A space or cavity at the entrance to a canal, especially that of the nose, inner ear, or vagina.
villus
(vil´us) A minute projection that extends outward into the lumen from the mucosal layer of the small intestine.
virulent
(vir´yuu-lent) Pathogenic; able to cause disease.
viscera
(vis´er-a) The organs within the abdominal or thoracic cavities.
visceral
(vis´er-al) Pertaining to the membranous covering of the viscera.
visceral peritoneum
(per´´u1-tuo-ne´um) A serous membrane that covers the surfaces of abdominal viscera.
visceral pleura
(ploor´ua) A serous membrane that covers the surfaces of the lungs.
visceroceptor
(vis´´er-uo-sep´tor) A sensory receptor located within body organs that responds to information concerning the internal environment.
vitreous humor
(vit´re-us hyoo´mer) The transparent gel that occupies the space between the lens and retina of the eyeball.
Volkmann's canal
(f=olk´manz) See perforating canal.
vulva
(vul´vua) The external genitalia of the female that surround the opening of the vagina.
white matter
Axions are surrounded by myelin, a fatty substance which is almost white in colour. Areas of the central nervous system rich in axions constitute the white matter (see grey matter).
wormian bone
(wer´me-an) See sutural bone.
xiphoid
Greek xiphos = a sword, and eidos = shape or form; hence, sword-shaped
yellow marrow
(mar´o) Specialized lipid storage tissue within bone cavities.
zygapophyseal joints
pairs of synovial facet joints between transverse processes in the spine.
zygote
(zi´g=ot) A fertilized egg cell formed by the union of a sperm cell and an ovum.
