| first-order reaction | A reaction the rate of which is proportional to the concentration of the single substance undergoing change; radioactive decay is a first-order process, defined by the equation -(dN/dt)=kN, where N is the number of atoms subject to decay (reaction), t is time, and k is the first-order decay (reaction) constant, i.e., the fraction of all atoms decaying per unit of time. See: decay constant, order. (05 Mar 2000) |
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| first parallel pelvic plane | The upper opening of the true pelvis, bounded anteriorly by the pubic symphysis and the pubic crest on either side, laterally by the iliopectineal lines, and posteriorly by the promontory of the sacrum. Synonym: apertura pelvis superior, aditus pelvis, first parallel pelvic plane, pelvic brim, pelvic inlet, pelvic plane of inlet, plane of inlet. (05 Mar 2000) |
| first rank symptoms | Those symptom's that, when present, indicate that the diagnosis of schizophrenia is likely, provided that organic or toxic aetiology is ruled out: delusion of control, thought broadcasting, thought withdrawal, thought insertion, hearing one's thoughts spoken aloud, auditory hallucinations that comment on one's behaviour, and auditory hallucinations in which two voices carry on a conversation. Synonym: first rank symptoms, schneiderian first rank symptoms. (05 Mar 2000) |
| first-set rejection | Allograft transplantation between two organisms not previously sensitised to the graft tissue. Necrosis of the graft usually occurs within 10 days of transplantation. (05 Mar 2000) |
| first stage of labour | The part of labour when the cervix dilates fully (to 10 centimeters). The first stage of labour is also called the stage of dilatation. (12 Dec 1998) |
| first temporal convolution | A longitudinal gyrus on the lateral surface of the temporal lobe between the lateral (sylvian) fissure and the superior temporal sulcus. Synonym: gyrus temporalis superior, first temporal convolution, superior temporal convolution. (05 Mar 2000) |
| first visceral cleft | <anatomy> The cleft between the hyoid and mandibular arches of the embryo; the external auditory meatus is developed from its dorsal portion. Synonym: first visceral cleft. (05 Mar 2000) |
| bridging hepatic necrosis | Area of liver necrosis which bridges adjacent portal areas and central veins; subsequent post-necrotic collapse and fibrosis is likely to result in cirrhosis. (05 Mar 2000) |
| right branch of proper hepatic artery | <anatomy, artery> Right branch of proper hepatic artery; terminal branch of proper hepatic artery supplying right lobe of liver; branch: cystic artery. Synonym: ramus dexter arteriae hepaticae propriae, right branch of proper hepatic artery. (05 Mar 2000) |
| right hepatic artery | <anatomy, artery> Right branch of proper hepatic artery; terminal branch of proper hepatic artery supplying right lobe of liver; branch: cystic artery. Synonym: ramus dexter arteriae hepaticae propriae, right branch of proper hepatic artery. (05 Mar 2000) |
| right hepatic duct | The duct that transmits bile to the common hepatic duct from the right half of the liver and the right part of the caudate lobe. Synonym: ductus hepaticus dexter. (05 Mar 2000) |
| right hepatic veins | Veins draining much of the right lobe of the liver (posterior segments [VI & VII] and part of the inferior anterior segment [V]) which merge to form a single or sometimes double trunk, draining into the right side of the suprahepatic portion of the inferior vena cava (between the superior surface of the liver and the diaphragm); when single, it is the largest vein of the liver. Synonym: venae hepaticae dextrae. (05 Mar 2000) |
| middle hepatic veins | Veins draining the central portion of the liver (the superior anterior segment [VIII] and the left side of the inferior anterior segment [V] of the right lobe and the medial segment [IV] of the left lobe) which join to form a trunk that merges with that of the left hepatic veins about 90% of the time prior to entering the left side of the inferior vena cava. Synonym: venae hepaticae mediae. (05 Mar 2000) |
| common hepatic artery | <anatomy, artery> Origin, coeliac; branches, right gastric, gastroduodenal, and proper hepatic. Synonym: arteria hepatica communis. (05 Mar 2000) |
| common hepatic duct | The part of the biliary duct system that is formed by the confluence of right and left hepatic ducts. at the porta hepatis it is joined by the cystic duct to become the common bile duct. Synonym: ductus hepaticus communis, hepatocystic duct. (05 Mar 2000) |