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Medical Dictionary


Acronym for analysis of variance.

anovesical (a′no-ves′i-kal)
Relating in any way to both anus and urinary bladder.

anovular (an-ov′u-lar)
SYN: anovulatory.

anovulation (an-ov-u-la′shun)
Suspension or cessation of ovulation.

anovulatory (an-ov′u-la-tor-e)
Absence of the development of a mature graafian follicle and/or the discharge of the ovum during a menstrual cycle. SYN: anovular.

anoxemia (an-ok-se′me-a)
Absence of oxygen in arterial blood; formerly often used to include moderate decrease in oxygen now properly distinguished as hypoxemia. [G. an- priv. + oxygen + G. haima, blood]

anoxia (an-ok′se-a)
Absence or almost complete absence of oxygen from inspired gases, arterial blood, or tissues; to be differentiated from hypoxia. [G. an- priv. + oxygen] anemic a. a term formerly considered synonymous with anemic hypoxia, but now reserved for extremely severe cases in which oxygen and functional erythrocyte volume are almost completely lacking. anoxic a. a term formerly considered synonymous with hypoxic hypoxia, but now reserved for extremely severe cases in which oxygen is almost completely lacking. diffusion a. diffusion hypoxia severe enough to result in the absence of oxygen in alveolar gas. histotoxic a. poisoning of the respiratory enzyme systems of the tissues, as in the inhibition of cytochrome oxidase by cyanides; owing to the inability of tissue cells to utilize oxygen, its tension in arterial and capillary blood is usually greater than normal. a. neonatorum any a. observed in newborn infants. oxygen affinity a. a. due to inability of hemoglobin to release oxygen. stagnant a. stagnant hypoxia severe enough to result in the absence of oxygen in tissues.

anoxic (an-ok′sik)
Denoting or characteristic of anoxia.

Abbreviation for atrial natriuretic peptide.

G.V., 20th century Lebanese physiologist in Britain. See A. phenomenon.

Abbreviation for anterior nasal spine; autonomic nervous system.

ansa, gen. and pl. ansae (an′sa, -se) [TA]
Any anatomical structure in the form of a loop or an arc. SEE ALSO: loop. [L. loop, handle] a. cervicalis [TA] a loop in the cervical plexus consisting of fibers from the first three cervical nerves. Fibers from a loop between the C1 and C2 spinal nerves accompany the hypoglossal nerve for a short distance, leaving it as the superior root of the a. cervicalis. Fibers from a loop between the C2 and C3 spinal nerves form the inferior root of the a. cervicalis. Most commonly, the roots merge, forming the a. cervicalis, which gives rise to branches innervating infrahyoid muscles. SYN: cervical loop, loop of hypoglossal nerve. Haller a. SYN: communicating branch of facial nerve with glossopharyngeal nerve. Henle a. SYN: nephronic loop. a. hypoglossi obsolete term for a. cervicalis. lenticular a. SYN: lenticular loop. a. lenticularis [TA] SYN: lenticular loop. ansae nervorum spinalium SYN: loops of spinal nerves, under loop. peduncular a. SYN: a. peduncularis. a. peduncularis [TA] a complex fiber bundle curving around the medial edge of the internal capsule and connecting the anterior part of the temporal lobe (temporal cortex), amygdala, and olfactory cortex with the mediodorsal nucleus of the thalamus; it enters the thalamus as a component of the inferior thalamic peduncle which also contains a major part of the fibers connecting the mediodorsal nucleus to the orbitofrontal cortex. SYN: peduncular a., peduncular loop, Reil a.. Reil a. SYN: a. peduncularis. a. sacralis a nerve cord connecting one or both of the sympathetic nerve trunks with the ganglion impar. a. subclavia [TA] a nerve cord connecting the middle cervical and inferior cervical or stellate sympathetic ganglia, forming a loop around the subclavian artery. SYN: subclavian loop, Vieussens a., Vieussens loop. Vieussens a. SYN: a. subclavia.

ansate (an′sat)
SYN: ansiform.

1. (an′ser-in)Resembling or characteristic of a goose. See cutis anserina, pes anserinus. 2. (an′ser-en) Na-(β-Alanyl)-π-methyl-l-histidine;present in muscle and brain. SYN: N-methylcarnosine. [L. anserinus, fr. anser, goose]

Abbreviation for American National Standards Institute.

ansiform (an′si-form)
In the shape of a loop or arc. SYN: ansate. [L. ansa, handle, + forma, shape]

ansotomy (an-sot′o-me)
1. Surgical division of a loop, usually a constricting loop. 2. Section of the ansa lenticularis for treatment of striatal syndromes. [L. ansa, handle + G. tome, cutting]

One of the most numerous insects (order Hymenoptera), characterized by an extraordinary development of colonial dwelling and caste specialization. black imported fire a. SYN: Solenopsis richteri. fire a. any of several species in the genus Solenopsis whose bite causes a fiery, burning sensation and sometimes severe allergic reactions. SEE ALSO: solenopsin A. harvester a. SYN: Pogonomyrmex. red imported fire a. SYN: Solenopsis invicta. velvet a. a wingless mutilid wasp (family Mutilidae, order Hymenoptera) known for its venomous sting.

See anti-.

antacid (ant-as′id)
1. Neutralizing an acid. 2. Any agent that reduces or neutralizes acidity, as of the gastric juice or any other secretion ( e.g., calcium carbonate, magnesium hydroxide). SYN: antiacid.

antagonism (an-tag′on-izm)
1. Denoting mutual opposition in action between structures, agents, diseases, or physiologic processes. Cf.:synergism. 2. The situation in which the combined effect of two or more factors is smaller than the solitary effect of any one of the factors. SYN: mutual resistance. [G. antagonisma, from anti, against, + agonizomai, to fight, fr. agon, a contest] bacterial a. the inhibition of one bacterium by another.

antagonist (an-tag′o-nist)
Something opposing or resisting the action of another; certain structures, agents, diseases, or physiologic processes that tend to neutralize or impede the action or effect of others. Cf.:synergist. α-adrenoceptor a. SYN: α-adrenergic blocking agent. β-adrenoreceptor a. SYN: β-adrenergic blocking agent. aldosterone a. an agent that opposes the action of the adrenal hormone aldosterone on renal tubular mineralocorticoid retention; these agents, e.g., spironolactone, are useful in treating the hypertension of primary hyperaldosteronism, or the sodium retention of secondary hyperaldosteronism. associated a. one of two muscles or groups of muscles which pull in nearly opposite directions, but which, when acting together, move the part in a path between their diverging lines of action. calcium a. SYN: calcium channel-blocking agent. competitive a. an antimetabolite. enzyme a. an antimetabolite or inhibitor of enzyme action. folic acid antagonists modified pterins, such as aminopterin and methotrexate, that interfere with the action of folic acid and thus produce the symptoms of folic acid deficiency; have been used in cancer chemotherapy and inflammatory disorders. 5-hydroxy tryptamine antagonists agents that block serotonin receptors and hence interfere with the biological actions of serotonin (5-HT). insulin a. substances in the β- and γ-globulin or β1-lipoprotein fractions of serum that may induce a functional insulin deficiency; may include nonprecipitating antibodies against nonhuman insulin. leukotriene receptor a. a class of agents, of which zileuton, montelukast, zafirlukast are the best known, used in the prophylactic and chronic treatment of asthma in older children and adults; these drugs are not bronchodilators in themselves, but act by interfering with the leukotriene-mediated inflammatory process present in asthma. muscarinic a. drugs that bind with muscarinic cholinergic receptors but do not activate them, thus preventing access to acetylcholine; examples include atropine, scopolamine, propantheline, and pirenzepine. opioid antagonists agents such as naloxone and naltrexone that have high affinity for opiate receptors but do not activate these receptors. These drugs block the effects of exogenously administered opioids such as morphine, heroin, meperidine, and methadone, or of endogenously released endorphins and enkephalins.

antalgesia (ant-al-je′ze-a)
Rarely used term for lowering of a previous elevation in pain threshold. [anti- + G. algesis, sense of pain]

antalgic (ant-al′jik)
SYN: analgesic (2) .

antalkaline (ant-al′ka-lin)
Reducing or neutralizing alkalinity.

antaphrodisiac (ant′af-ro-diz′e-ak)
SYN: anaphrodisiac.

antaphroditic (ant′af-ro-dit′ik)
1. SYN: anaphrodisiac. 2. SYN: antivenereal.

antarthritic (ant′ar-thrit′ik)
Rarely used term for: SYN: antiarthritic.

antasthenic (ant-as-then′ik)
1. Strengthening or invigorating. 2. An agent possessing such qualities. [anti- + G. astheneia, weakness]

antasthmatic (ant-az-mat′ik)
SYN: antiasthmatic.

antatrophic (ant-a-trof′ik)
1. Preventing or curing atrophy. 2. An agent that promotes the restoration of atrophied structures.

antazoline hydrochloride (an-taz′o-len)
A histamine-antagonizing agent used in treating allergy; also available as a. phosphate. SYN: phenazoline hydrochloride.

Before, in front of (in time or place or order). SEE ALSO: pre-, pro- (1) . [L. ante, before, in front of]

antebrachial (an′te-bra′ke-al)
Relating to the forearm.

antebrachium (an-te-bra′ke-um) [TA]
SYN: forearm. [ante- + L. brachium, arm]

antecardium (an-te-kar′de-um)
SYN: precordia.

antecedent (an-te-se′dent)
A precursor. [L. antecedo, to go before] plasma thromboplastin a. (PTA) SYN: factor XI.

ante cibum (an′te si′bum)
Before a meal. The plural is ante cibos, before meals. [L.]

antecubital (an-te-ku′bi-tal)
In front of the elbow. [ante- + L. cubitum, elbow]

antefebrile (an-te-feb′ril)
Rarely used term for antepyretic. [ante- + L. febris, fever]

anteflex (an′te-fleks)
To bend anteriorly (forward) or cause to bend anteriorly. [ante- + L. flecto, pp. flexus, to bend]

anteflexion (an-te-flek′shun)
A bending forward; a sharp forward curve or angulation; denoting especially the normal forward bend in the uterus at the junction of corpus and cervix uteri. a. of iris rarely used term for an iris that is, in part, folded forward after a severe iridodialysis so that the pigmented layer faces forward.

antegrade (an′te-grad)
In the direction of normal movement, as in blood flow or peristalsis. [ante- + L. gradior, to walk]

antemortem (an′te-mor-tem)
Before death. Cf.:postmortem. [ante- + L. mors (mort-), death]

antenatal (an-te-na′tal)
SYN: prenatal. [ante- + L. natus, birth]

antepartum (an′te-par-tum)
Before labor or childbirth. Cf.:intrapartum, postpartum. [ante- + L. pario, pp. partus, to bring forth]

anteposition (an′te-po-si′shun)
Forward or anterior position.

antepyretic (an′te-pi-ret′ik)
Before the occurrence of fever; before the period of reaction following shock. [ante- + G. pyretos, fever]

anterior (an-ter′e-or)
1. [NA] In human anatomy, denoting the front surface of the body; often used to indicate the position of one structure relative to another, i.e., situated nearer the front part of the body. SYN: ventral (2) [TA] , ventralis [TA] . 2. Near the head or rostral end of certain embryos. 3. Undesirable and confusing substitute for cranial in quadrupeds. In veterinary anatomy, a. is restricted to parts of the eye and inner ear. 4. Before, in relation to time or space. [L.]

Anterior. [L. anterior, more before, earlier, fr. ante, before, + -r- -ior, more]

anteroexternal (an′ter-o-eks-ter′nal)
In front and to the outer side.

anterograde (an′ter-o-grad)
1. Moving forward. Cf.:antegrade. 2. Extending forward from a particular point in time; used in reference to amnesia. [L. gradior, pp. gressus, to step, go]

anteroinferior (an′ter-o-in-fer′e-or)
In front and below.

anterointernal (an′ter-o-in-ter′nal)
In front and to the inner side.

anterolateral (an′ter-o-lat′er-al)
In front and away from the middle line.

anteromedial (an′ter-o-me′de-al)
In front and toward the middle line.

anteromedian (an′ter-o-me′de-an)
In front and in the central line.

anteroposterior (an′ter-o-pos-ter-e-er)
1. Relating to both front and rear. 2. In x-ray imaging, describing the direction of the beam through the patient (projection) from anterior to posterior, e.g., an A-P projection of the abdomen; or the direction of view (A-P view) when a film is viewed as if facing the patient (anterior to posterior) regardless of projection.

anterosuperior (an′ter-o-soo-pe′re-er)
In front and above.

anterotic (ant-er-ot′ik)
Pertaining to an effort to avoid erotic feelings. [anti- + G. erotikos, pertaining to love]

antesystole (an-te-sis′to-le)
Premature activation of the ventricle responsible for the pre-excitation syndrome of the Wolff-Parkinson-White or Lown-Ganong-Levine types.

anteversion (an-te-ver′shun)
Turning forward, inclining forward as a whole without bending. [ante- + Mediev. L. versio, a turning]

anteverted (an-te-vert′ed)
Tilted forward; in a position of anteversion.


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