| splanchnic circulation | The circulation of blood through the vessels supplying the abdominal viscera. (12 Dec 1998) |
|---|---|
| systemic circulation | The circulation of blood through the arteries, capillaries, and veins of the general system, from the left ventricle to the right atrium. Synonym: greater circulation. (05 Mar 2000) |
| thebesian circulation | The system of smaller veins in the myocardium. (05 Mar 2000) |
| embryonic circulation | The basic plan of the circulation of a young mammalian embryo, at first similar to that in aquatic forms, with an unpartitioned heart and conspicuous aortic arches in the branchial region; as gestation progresses, the arrangement of the major blood vessels gradually approaches that of an adult, but the routing of blood through the heart, characteristic of an adult, cannot be attained until lung breathing begins at birth. (05 Mar 2000) |
| enterohepatic circulation | Recycling through liver by excretion in bile, reabsorption from intestines into portal circulation, passage back into liver, and re-excretion in bile. (12 Dec 1998) |
| extracorporeal circulation | Diversion of blood flow through a circuit located outside the body but continuous with the bodily circulation. (12 Dec 1998) |
| uteroplacental circulation | The circulation of blood through the uterus and placenta. (12 Dec 1998) |
| foetal circulation | The blood circulation in the foetus before birth. Before birth, the blood from the heart headed for the lungs in the aptly named pulmonary artery is shunted away from the lungs and returned to the greatest of arteries, the aorta. This arterial shunting occurs through a short vessel called the ductus arteriosus. When the shunt is open, it is said to be patent (pronounced pá tent). The ductus arteriosus usually tourniquets itself off at or shortly after birth. After closure of the ductus, blood is permitted from that time on to course freely to the lungs. Sometimes, however, the patent ductus arteriosus (PDA) persists and simply will not close by itself. Surgery is then done to ligate (tie off) the ductus PDA ligation is a closed-heart operation. Historically, it was one of the earliest surgical procedures performed in children with cardiovascular disease. (12 Dec 1998) |
| lesser circulation | The circulation of blood through the lungs. (12 Dec 1998) |
| liver circulation | The circulation of blood through the vessels of the liver. (12 Dec 1998) |
| lymph circulation | The slow passage of lymph through the lymphatic vessels and glands. (05 Mar 2000) |
| Abbe theory of image formation | <optics, physics> Abbe's theory is based on the fact that a non-self-luminous particle, which is illuminated by an extraneous source, gives rise to diffracted light rays, in addition to the dioptric pencil. He stated that to form a good microscopical image as many of the diffracted rays as possible should be intercepted by the objective. With closely ruled lines, his theory is easily demonstrated by observing the back lens of the objective, for here the diffracted rays can be observed directly if the aperture diaphragm is closed. It can be shown that, when the illumination is arranged to exclude the diffracted images, resolution is lost. (11 Mar 1998) |
| adsorption theory of narcosis | That a drug becomes concentrated at the surface of the cell as a result of adsorption, and thus alters permeability and metabolism. (05 Mar 2000) |
| Altmann's theory | A theory that protoplasm consists of granular particles (called bioblasts) that are clustered and enclosed in indifferent matter. (05 Mar 2000) |
| Arrhenius-Madsen theory | That the reaction of an antigen with its antibody is a reversible reaction, the equilibrium being determined according to the law of mass action by the concentrations of the reacting substances. (05 Mar 2000) |