| sperm nucleus | The head of the spermatozoon, which becomes spheroidal, after entering the ovum. See: pronucleus. (05 Mar 2000) |
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| sperm-ovum interactions | Interactive processes between the ovum and the spermatozoon. (12 Dec 1998) |
| sperm tail | The posterior, filiform part of spermatozoa, which provides sperm motility. (12 Dec 1998) |
| sperm transport | Passive transport or active migration of spermatozoa from the testes through the male genital system as well as within the female genital system. (12 Dec 1998) |
| sperm whale | <zoology> A very large toothed whale (Physeter macrocephalus), having a head of enormous size. The upper jaw is destitute of teeth. In the upper part of the head, above the skull, there is a large cavity, or case, filled with oil and spermaceti. This whale sometimes grows to the length of more than eighty feet. It is found in the warmer parts of all the oceans. Called also cachalot, and spermaceti whale. Pygmy sperm whale, a toothed cetacean (Hyperoodon bidens), found on both sides of the Atlantic and valued for its oil. The adult becomes about twenty-five feet long, and its head is very large and thick. Called also bottle-nosed whale. Source: Websters Dictionary (01 Mar 1998) |
| nematode sperm | The nematode Caenorhabditis elegans has an unusual amoeboid spermatozoon that is actively motile yet appears to lack both actin and tubulin. (18 Nov 1997) |
| intracytoplasmic sperm injection | <gynaecology> The direct injection of a single sperm into an egg. (09 Oct 1997) |
| Abbe test plate | <equipment> A long, wedge-shaped coverslip about 0.20 mm thick at one end and 0.10 to 0.12 mm at the other end coated chemically with a silver film on which are ruled horizontal lines. at each variation in thickness of 0.01 mm there are vertical lines. By means of oblique illumination and by focusing on different portions of the plate, it is possible to determine the optimum coverslip thickness for any objective and also, for microscopes with drawtubes, the tube length for best objective performance. The approximate freedom from spherical and chromatic aberrations can also be estimated. Small isolated bits of silver near the edges of the lines form good objects for the star test (05 Aug 1998) |
| acetone test | A test for ketonuria; the suspected urine is shaken up with a few drops of sodium nitroprusside, and strong ammonia water is then gently poured over the mixture; if acetone is present, a magenta ring forms at the line of contact; tablets containing sodium nitroprusside and alkali are now more commonly used. (05 Mar 2000) |
| achievement test | A standardised test used to measure acquired learning, e.g., competence in a specific subject area such as reading or arithmetic, in contrast to an intelligence test which is a useful index of potential ability or learning. (05 Mar 2000) |
| acidified serum test | Lysis of the patient's red cells in acidified fresh serum, specific for paroxysmal nocturnal haemoglobinuria. Synonym: Ham's test. (05 Mar 2000) |
| acid loading test | <nephrology> This is a test used in the diagnosis of renal tubular acidosis. The patient takes ammonium chloride capsules for 3 days to acidify the blood (lower blood pH). A sample of the urine and the blood is then collected and the results are interpreted. (27 Sep 1997) |
| acid perfusion test | <gastroenterology, investigation> A test used to diagnosis gastrooesophageal reflux disease. This investigation requires that the patient swallow 3 tiny tubes into the stomach. A mixture of hydrochloric acid (like stomach acid) and saline are alternatively injected into the tubes. The patient then reports any symptoms they may have. Some patients may vomit. (13 Nov 1997) |
| acid phosphatase test for semen | A screening test for semen by determining acid phosphatase content; because seminal fluid contains high concentrations of acid phosphatase, while other body fluids and extraneous foreign materials have very low concentrations, high values of acid phosphatase on vaginal aspirate or lavage, or on wash fluid from stains, render positive identification of semen, even if the male is aspermic. (05 Mar 2000) |
| acid reflux test | A test to detect gastroesophageal reflux by monitoring oesophageal pH by an electrode in the distal oesophagus either basally or after acid is instilled into the stomach. (05 Mar 2000) |