|Medical Dictionary - Dictionary of Medicine and Human Biology|
volt (v, V) (volt)
The unit of electromotive force; the electromotive force that will produce a current of 1 A in a circuit that has a resistance of 1 ohm; i.e., joule per coulomb. [Alessandro Volta, It. physicist, 1745–1827]
Electromotive force, pressure, or potential expressed in volts.
An apparatus for measuring the strength of a galvanic current by its electrolytic action. [volt + G. metron, measure]
A unit of electrical power; the product of 1 V by 1 A; equivalent to 1 W or 11000 kW.
An apparatus for measuring the electromotive force or difference of potential.
Friedrich E.R., German laryngologist, 1819–1889. See V. disease.
volume (V, V) (vol′yum)
Space occupied by matter, expressed usually in cubic millimeters, cubic centimeters, liters, etc. See water. SEE ALSO: capacity. [L. volumen, something rolled up, scroll, fr. volvo, to roll] atomic v. the atomic weight of an element divided by its density in the solid state; the v. of the gram-atomic weight of a solid element. v. averaging in computed tomography or magnetic resonance imaging, the effect of expressing the average density of a voxel as a pixel in the image; the greater the slice thickness, the more averaging is necessary, with loss in density resolution. closing v. (CV) the lung v. at which the flow from the lower parts of the lungs becomes severely reduced or stops during expiration, presumably because of airway closure; measured by the sharp rise in expiratory concentration of a tracer gas that had been inspired at the beginning of a breath that started from residual v.. distribution v. the v. throughout which an added tracer substance appears to have been evenly distributed, calculated by dividing the amount of tracer added by its concentration after equilibration. end-diastolic v. the capacity or the amount of blood in the ventricle immediately before a cardiac contraction begins; a measurement of cardiac filling between beats, related to diastolic function. end-systolic v. the capacity or the amount of blood in the ventricle at the end of the ventricular ejection period and immediately preceding the beginning of ventricular relaxation; a measurement of the adequacy of cardiac emptying, related to systolic function. expiratory reserve v. (ERV) the maximal v. of air (about 1000 mL) that can be expelled from the lungs after a normal expiration. SYN: reserve air, supplemental air. extracellular fluid v. (ECFV) the fraction of body water not in cells, about 25% of body weight: it consists of plasma water (4.5% of body weight), water between cells (interstitial water-lymph, 11.5% of body weight), water in dense bone and connective tissue (7.5% of body weight), and water secretions. See entries under entries under water.. SEE ALSO: intracellular fluid. forced expiratory v. (FEV) the maximal v. that can be expired in a specific time interval when starting from maximal inspiration. A subscript annotation normally indicates the number of seconds the patient has been expiring e.g., FEV30–60. inspiratory reserve v. (IRV) the maximal v. of air that can be inspired after a normal inspiration; the inspiratory capacity less the tidal v.. SYN: complemental air. mean corpuscular v. (MCV) the average v. of red cells, calculated from the hematocrit and the red cell count, in erythrocyte indices. minute v. the v. of any gas or fluid moved per minute; e.g., cardiac output or the respiratory minute v.. packed cell v. the v. of the blood cells in a sample of blood after it has been centrifuged in the hematocrit; normally, it amounts to 45% of the blood sample. partial v. the actual v. occupied by one species of molecule or particle in a solution; the reciprocal of the density of the molecule. residual v. (RV) the v. of air remaining in the lungs after a maximal expiratory effort. SYN: residual air, residual capacity. respiratory minute v. (RMV) the minute v. of breathing; the product of tidal v. times the respiratory frequency. See pulmonary ventilation. resting tidal v. the tidal v. under normal conditions, i.e., in the absence of exercise or other conditions that stimulate breathing. standard v. the v. of an ideal gas at standard temperature and pressure, approximately 22.414 L. stroke v. the v. pumped out of one ventricle of the heart in a single beat. SYN: stroke output. tidal v. (VT) the v. of air that is inspired or expired in a single breath during regular breathing. SYN: tidal air.
A device for determining the volume of a solid by measuring the amount of liquid it displaces. SYN: volumometer. [volume + G. metron, measure]
Relating to measurement by volume.
Relating or acting in obedience to the will; not obligatory. [L. voluntarius, fr. voluntas, will, fr. volo, to wish]
Causing or caused by sensual pleasure; given to gratification of the senses. [L. voluptuosus, fr. voluptas, pleasure]
Rolled up; convoluted. [L. voluta, a scroll, fr. volvo, pp. volutus, to roll]
A nucleoprotein complex found as cytoplasmic granules in certain bacteria, yeasts, and protozoa (such as trypanosome flagellates) which serves as food reserves. SYN: v. granules.
A genus of highly organized colonial green flagellates of the class Phytomastigophorea. [L. volvo, to roll]
A twisting of the intestine causing obstruction; if left untreated may result in vascular compromise of the involved intestine. [L. volvo, to roll] cecal v. rotation and twisting of the cecum toward the left upper quadrant, with ascending colon obstruction; associated with a cecum on a long mesentery. gastric v. twisting of the stomach that may result in obstruction and impairment of the blood supply to the organ; it can occur in paraesophageal hernia and occasionally in eventration of the diaphragm. See organoaxial. mesenteroaxial v. a type of gastric v. in which the axis of twist is parallel to the line of the gastric mesentery. SEE ALSO: organoaxial. sigmoid v. relatively common location of v., with obstruction either proximal or distal to the sigmoid segment.
vomer, gen. vomeris (vo′mer, vo′mer-is) [TA]
A flat bone of trapezoidal shape forming the inferior and posterior portion of the nasal septum; it articulates with the sphenoid, ethmoid, two maxillae, and two palatine bones. [L. ploughshare] v. cartilagineus SYN: vomeronasal cartilage.
Relating to the vomer.
Relating to the vomer and the base of the skull.
Relating to the vomer and the nasal bone.
1. To eject matter from the stomach through the mouth. 2. Vomitus; the matter so ejected. SYN: vomitus (2) . [L. vomo, pp. vomitus, to v.] Barcoo v. attacks of nausea and vomiting accompanied by bulimia affecting those living in the interior of the southern part of Australia. bilious v. v. containing large amounts of bile suggestive of bowel obstruction distal to the papilla of Vater. black v. the coffee-ground-colored material that is vomited, specifically, in severe yellow fever. SEE ALSO: coffee-ground v.. SYN: vomitus niger. coffee-ground v. v. consisting of fresh or old blood. SEE ALSO: black v..
The ejection of matter from the stomach in retrograde fashion through the esophagus and mouth. SYN: emesis (1) , vomition, vomitus (1) . cerebral v. v. due to intracranial disease, especially elevated intracranial pressure. cyclic v. a syndrome of recurrent bouts of v. seen especially in preverbal children; many affected children later develop typical migraine headaches. dry v. SYN: retching. epidemic v. virus caused by Norwalk virus, a 27-nm RNA virus in the family Caliciviridae frequently occurring in a group of people ( e.g., in a school or small community) suddenly and without prodromal illness or malaise, is intense while it lasts, but ceases abruptly after 24–48 hours; symptoms are headache, abdominal pain, giddiness, and diarrhea in most of the cases, and extreme prostration in about 75%. SYN: epidemic nausea. fecal v. vomitus with appearance and/or odor of feces suggestive of long-standing distal small bowel or colonic obstruction. SYN: copremesis, stercoraceous v.. morning v. v. occurring on rising or immediately after breakfast in some women during early pregnancy. SYN: morning sickness. pernicious v. uncontrollable v.. v. of pregnancy v. occurring in the early months of pregnancy. projectile v. expulsion of the contents of the stomach with great force. psychogenic v. v. associated with emotional distress and anxiety. retention v. v. due to mechanical obstruction, usually hours after ingestion of a meal. stercoraceous v. SYN: fecal v..
SYN: vomiting. [L. vomitio, fr. vomo, to vomit]
1. SYN: vomiting. 2. SYN: vomit (2) . [L. a vomiting, vomit] v. cruentes SYN: hematemesis. v. marinus SYN: seasickness. v. niger SYN: black vomit.
Often abbreviated to v. For names with this prefix not found here, see under the principal part of the name.
Victor, Austrian histologist, 1842–1925. See Ebner glands, under gland, Ebner reticulum, imbrication lines of von Ebner, under line, incremental lines of von Ebner, under line.
Constantin F., Austrian neurologist, 1876–1931. See von Economo disease.
D. P., German pathologist, 1858–1920. See Hansemann macrophage.
Eugen, German ophthalmologist, 1867–1939. See von Hippel-Lindau syndrome.
Julius, 19th century Austro-Hungarian pathologist. See von Kossa stain.
See von Recklinghausen disease. See Recklinghausen.
Leopold, Austrian laryngologist, 1837-1908. See Paget-von Schrötter syndrome.
E.A., Finnish physician, 1870–1949. See von Willebrand disease.
N., Dutch radiologist, 1879–1927. See V. disease.
vortex, pl .vortices (vor′teks, vor′ti-sez)
1. SYN: verticil. 2. SYN: whorl (5) . 3. SYN: v. lentis. [L. whirlpool, whorl, fr. verto or vorto, to turn around] v. coccygeus a spiral arrangement of coarse hairs sometimes present over the region of the coccyx. SYN: coccygeal whorl. v. cordis [TA] SYN: v. of heart. Fleischer v. SYN: cornea verticillata. v. of heart [TA] a spiral arrangement of muscular fibers at the apex of the heart. SYN: v. cordis [TA] , whorl (2) . v. lentis one of the stellar figures on the surface of the lens of the eye. SYN: v. (3) . vortices pilorum [TA] SYN: hair whorls, under whorl.
A genus of Ciliata of the order Peritrichida, bell-shaped and with a spiral of cilia around the adoral zone; various free-living species have been found at times in the feces, urine, and mucous discharges. [Mod. L. dim. of L. vortex, a whorl]
Plural of vortex.
Arranged in a whorl. [L. vorticosus, fr. vortex, a whorl]
Adolf, German pathologist, 1855–1925. See V. lenticular ring.
SYN: voice. [L.] v. choleraica a peculiar, hoarse, almost inaudible voice of a sufferer in the last stage of Asiatic cholera.
A contraction for volume element, which is the basic unit of CT or MR reconstruction; represented as a pixel in the display of the CT or MR image.
One who practices voyeurism.
The practice of obtaining sexual pleasure by looking, especially at the naked body or genitals of another or at erotic acts between others. SYN: scopophilia. [Fr. voir, to see]
Abbreviation for vasopressin; variegate porphyria.
Abbreviation for vocal resonance.
Abbreviation for volumetric solution.
Abbreviation for volume unit.
Ordinary; of the usual type. [L. fr. vulgus, a crowd]
Edme F.A., French physician, 1826–1887. See V. atrophy.
vulsella, vulsellum (vul-sel′a, -lum)
SYN: v. forceps. [L. pincers, fr. vello, pp. vulsus, to pluck]
vulva, pl .vulvae (vul′va)
[NA] The external genitalia of the female, comprised of the mons pubis, the labia majora and minora, the clitoris, the vestibule of the vagina and its glands, and the opening of the urethra and of the vagina. SYN: cunnus, pudendum femininum, trema (2) . [L. a wrapper or covering, seed covering, womb, fr. volvo, to roll]
vulvar, vulval (vul′var, vul′val)
Relating to the vulva.
Excision (either partial, complete, or radical) of the vulva. [vulva + G. ektome, excision]
Inflammation of the vulva. [vulva + G. -itis, inflammation] chronic atrophic v. an inflammation of atrophic vulvar skin, usually with severe pruritus. chronic hypertrophic v. obsolete term for swelling of the vulval tissues due to lymphatic obstruction; in some cases it may be caused by filariasis, with induration or ulceration of the skin. SYN: elephantiasis vulvae. follicular v. inflammation of the vulvar hair follicles.
The vulva. [L. vulva]
Relating to the vulva and the clitoris.
Chronic vulvar discomfort with complaints of burning and superficial irritation.
Relating to the vulva and the uterus.
Relating to the vulva and the vagina.
Inflammation of both vulva and vagina.
Alternative surname of Wedensky, Nikolai I.
SYN: V-Y flap.
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