| ecosystem function | The collective intraspecific and interspecific interactions of the biota, such as primary and secondary production and mutualistic relationships. The interactions between organisms and the physical environment, such as nutrient cycling, soil development, water budgeting, and flammability. (09 Oct 1997) |
|---|---|
| function | The special, normal or proper physiologic activity of an organ or part. Origin: L. Functio, from fungi = to do (18 Nov 1997) |
| function corrector | A removable orthodontic appliance utilizing oral and facial muscle forces to move teeth and possibly change the relationship of the dental arches. (05 Mar 2000) |
| line spread function | A measure of the ability of a system to form sharp images; in radiology, determined by measuring the spatial density distribution on film of the X-ray image of a narrow slit in a dense metal, such as uranium; from this can be calculated the modulation transfer function. (05 Mar 2000) |
| liver function test | <investigation> A test that measures the blood serum level of several enzymes produced by the liver. An elevated liver function test is a sign of possible liver damage. Examples include: prothrombin time, PTT, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, gamma glutamyl transpeptidase, alkaline phosphatase and serum albumin. (14 Oct 1997) |
| lymphocyte function associated antigen | A member of the integrin family that is expressed on all leukocytes and binds to ICAM-1 and ICAM-2 on a variety of cells. (05 Mar 2000) |
| lymphocyte function-associated antigen-1 | A heterodimer molecule widely expressed on cells of haematopoietic origin. Cd11a antigen comprises the alpha chain and the CD18 antigen (antigens, CD18) the beta chain. Lfa-1 is a major receptor of T-cells, B-cells, and granulocytes. It mediates the leukocyte adhesion reactions underlying cytolytic conjugate formation, helper T-cell interactions, and antibody-dependent killing by natural killer cells and granulocytes. Intracellular adhesion molecule-1 (icam-1) has been defined as a ligand for lfa-1. (12 Dec 1998) |
| acid wave | A temporary increase in the acidity of the urine occurring during fasting. Synonym: acid wave. (05 Mar 2000) |
| alkaline wave | A period of urinary neutrality or even alkalinity after meals due to withdrawal of hydrogen ion for the purpose of secretion of the highly acid gastric juice. Synonym: alkaline wave. (05 Mar 2000) |
| alpha wave | Brain waves in the encephalogram which have a frequency of 8 to 13 per second. They are typical of the normal person awake and in a quiet resting state, and occur principally in the occipital region. (12 Dec 1998) |
| arterial wave | A wave in the jugular phlebogram due to transmission of carotid artery pulsation. B wave, the initial positive deflection in the electroretinogram, possibly arising from the inner nuclear layer of the retina. (05 Mar 2000) |
| A wave | The initial negative deflection in the electroretinogram, presumably reflecting retinal photoreceptor activity, an atrial deflection in an electrocardiogram recorded from within the atrium of the heart, the first positive deflection of the atrial and venous pulses due to atrial systole. (05 Mar 2000) |
| beta wave | <neurology> Brain waves in the electroencephalogram which have a frequency of 18 to 30 per second. They are typical during periods of intense activity of the nervous system, and occur principally in the parietal and frontal regions. (12 Dec 1998) |
| brain wave | Colloquialism for electroencephalogram. (05 Mar 2000) |
| brain wave complex | A specific combination of fast and slow electroencephalographic activity that recurs frequently enough to be identified as a discrete phenomenon. (05 Mar 2000) |