| GCSP | glycine cleavage system protein |
|---|---|
| TC | target cell; taurocholate; temperature compensation; teratocarcinoma; tertiary cleavage; tetracyclin... |
| ACD | absolute cardiac dullness; absolute claudication distance; acid-citrate-dextrose [solution]; actinom... |
| CAC | cardiac-accelerator center; cardiac arrest code; circulating anticoagulant |
| CAS | calcarine sulcus; calcific aortic stenosis; Cancer Attitude Survey; carbohydrate-active steroid; car... |
| yolk cleavage | Segmentation of the vitellus. (05 Mar 2000) |
|---|---|
| unequal cleavage | Cleavage producing blastomeres of different sizes at the two poles. (05 Mar 2000) |
| freeze cleavage | Method of specimen preparation for the electron microscope in which rapidly frozen tissue is cracked so as to produce a fracture plane through the specimen. The surface of the fracture plane is then shadowed by heavy metal vapour, strengthened by a carbon film and the underlying specimen is digested away, leaving a replica that can be picked up on a grid and examined in the transmission electron microscope. The great advantage of the method is that the fracture plane tends to pass along the centre of lipid bilayers and it is therefore possible to get en face views of membranes that reveal the pattern of Integral membrane proteins. The E face is the outer lamella of the plasma membrane viewed as if from within the cell, the P face the inner lamella viewed from outside the cell. Fracture planes also often pass along lines of weakness such as the interface between cytoplasm and membrane, so that outer and inner membrane surfaces can be viewed. Further information about the structure can be revealed by freeze etching. Extremely rapid freezing followed by deep etching has allowed the structure of the cytoplasm to be studied without the artefacts that might be introduced by fixation. (18 Nov 1997) |
| Amussat's valve | A series of crescentic folds of mucous membrane in the upper part of the cystic duct, arranged in a somewhat spiral manner. Synonym: plica spiralis ductus cystici, Amussat's valve, Heister's valve, spiral valve of cystic duct, valvula spiralis. (05 Mar 2000) |
| anterior cusp of atrioventricular valve | The anterior leaflet or valvule of either the tricuspid or mitral valves. Synonym: cuspis anterior valvae atrioventricularis dextrae/sinistrae. (05 Mar 2000) |
| anterior urethral valve | A crescentic horizontal fold in the proximal spongy urethra. (05 Mar 2000) |
| aortic valve | The heart valve that divides the left ventricle and the aorta. The aortic valve opens during left ventricular contraction and then closes to prohibit the backwash of oxygenated blood from the aorta into the ventricle. The aortic valve has 3 valve cusps. (27 Sep 1997) |
| aortic valve insufficiency | Backflow of blood from the aorta into the left ventricle, owing to imperfect functioning of the aortic semilunar valve. (12 Dec 1998) |
| aortic valve prolapse | The downward displacement of the cuspal material (misalignment of the cusps) below a line joining points of attachment of the aortic valve leaflets. The prolapsed cusp may occlude the ventricular septal defect during ventricular diastole. (12 Dec 1998) |
| aortic valve stenosis | Narrowing of the orifice of the aortic valve or of the supravalular or subvalvular regions. (12 Dec 1998) |
| artificial heart valve | <cardiology> A synthetic or porcine (pigskin) valve surgically placed into the heart to replace a defective or malfunctioning valve. The aortic and mitral valves are the most frequently replaced with artificial valves. (27 Sep 1997) |
| ball valve | Any of a variety of prosthetic cardiac valve's comprised of a ball within a retaining cage affixed to the orifice; when appropriately sized, used in aortic, mitral, or tricuspid position. (05 Mar 2000) |
| ball valve action | The intermittent blockage of a tube or outlet of a cavity by some object or material that permits passage in one direction but not in the other. (05 Mar 2000) |
| ball-valve thrombus | Ball thrombus intermittently occluding the mitral or tricuspid orifice. (05 Mar 2000) |
| Bauhin's valve | The bilabial prominence of the terminal ileum into the large intestine at the caecocolic junction as seen in cadavers; in the living individual it appears as a truncated cone with a star-shaped orifice. Synonym: valva ileocaecalis, Bauhin's valve, ileocaecal eminence, ileocolic valve, Tulp's valve, Tulpius' valve, valve of Varolius. (05 Mar 2000) |