| thrix | Synonym: hair. Origin: G. (05 Mar 2000) |
|---|---|
| thrix annulata | A rare condition in which the hair shows alternate pigmented and bright segments, the latter due to air cavities within the cortex. Synonym: leukotrichia annularis, pili annulati, thrix annulata, trichonosus versicolor. (05 Mar 2000) |
| throat | <botany> Refers to the top of a corolla tube, where the tube joins the lobes. (09 Oct 1997) |
| throatwort | <botany> A plant (Campanula Trachelium) formerly considered a remedy for sore throats because of its throat-shaped corolla. Source: Websters Dictionary (01 Mar 1998) |
| throb | To beat, or pulsate, with more than usual force or rapidity; to beat in consequence of agitation; to palpitate; said of the heart, pulse, etc. "My heart Throbs to know one thing." (Shak) "Here may his head lie on my throbbing breast." (Shak) Origin: OE. Robben; of uncertain origin; cf. Russ. Trepete a trembling, and E. Trepidation. A beat, or strong pulsation, as of the heart and arteries; a violent beating; a papitation: "The IMPATIENT throbs and longings of a soul That pants and reaches after distant good." (Addison) Source: Websters Dictionary (01 Mar 1998) |
| throe | 1. Extreme pain; violent pang; anguish; agony; especially, one of the pangs of travail in childbirth, or purturition. "Prodogious motion felt, and rueful throes." (Milton) 2. A tool for splitting wood into shingles; a frow. Origin: OE. Rowe, rave, AS. Rea a threatening, oppression, suffering, perhaps influenced by Icel. Ra a throe, a pang, a longing; cf. AS. Reowian to suffer. Source: Websters Dictionary (01 Mar 1998) |
| thromb- | See: thrombo-. (05 Mar 2000) |
| thrombase | <enzyme> Protease (34 kD) generated in blood clotting that acts on fibrinogen to produce fibrin. Consists of two chains, A and B, linked by a disulphide bond. B chain has sequence homology with pancreatic serine proteases: cleaves at Arg Gly. Thrombin is produced from prothrombin by the action either of the extrinsic system (tissue factor + phospholipid) or, more importantly, the intrinsic system (contact of blood with a foreign surface or connective tissue). Both extrinsic and intrinsic systems activate plasma factor X to form factor Xa which then, in conjunction with phospholipid (tissue derived or platelet factor 3) and factor V, catalyses the conversion. (18 Nov 1997) |
| thrombasthenia | <haematology> Condition in which there is defective platelet aggregation, though adherence is normal. See: Glanzmann's thrombasthenia. (18 Nov 1997) |
| thrombectomy | Procedure to remove a clot (a thrombus). (12 Dec 1998) |
| thrombelastography | Use of a thrombelastograph, which provides a continuous graphic record of the physical shape of a clot during fibrin formation and subsequent lysis. (12 Dec 1998) |
| thrombi | Plural of thrombus. (05 Mar 2000) |
| thrombin | <enzyme> Protease (34 kD) generated in blood clotting that acts on fibrinogen to produce fibrin. Consists of two chains, A and B, linked by a disulphide bond. B chain has sequence homology with pancreatic serine proteases: cleaves at Arg Gly. Thrombin is produced from prothrombin by the action either of the extrinsic system (tissue factor + phospholipid) or, more importantly, the intrinsic system (contact of blood with a foreign surface or connective tissue). Both extrinsic and intrinsic systems activate plasma factor X to form factor Xa which then, in conjunction with phospholipid (tissue derived or platelet factor 3) and factor V, catalyses the conversion. (18 Nov 1997) |
| thrombin time | Test of the conversion of fibrinogen to fibrin by thrombin in which clotting time of plasma mixed with a thrombin solution is measured. Time is prolonged by afibrinogenaemia, abnormal fibrinogen, or the presence of inhibitory substances, e.g., fibrin-fibrinogen degradation products, heparin. Reptilase, a thrombin-like enzyme unaffected by the presence of heparin, may be used in place of thrombin. (12 Dec 1998) |
| thrombinogen | A coagulation factor needed for the normal clotting of blood. In the cascade of events leading to the final clot, thrombinogen precedes thrombin (and so is a precursor to thrombin). In fact, thrombinogen gives rise to thrombin, and also called prothrombin. (12 Dec 1998) |