| PIVH | peripheral intravenous hyperalimentation; periventricular-intraventricular hemorrhage |
|---|---|
| PLA | peripheral laser angioplasty; phenyl lactate; phospholipase A; phospholipid antibody; placebo therap... |
| PLD | peripheral light detection; phospholipase D; platelet defect; polycystic liver disease; posterior la... |
| PLL | peripheral light loss; phase-locked loop; poly-L-lysine; pressure length loop; posterior longitudina... |
| PLN | peripheral lymph node; phospholamban |
| light harvesting system | Set of photosynthetic pigment molecules that absorb light and channel the energy to the photosynthetic reaction centre, where the light reactions of photosynthesis occur. In higher plants, contains chlorophyll and carotenoids and is present in two slightly different forms in photosystems I and II. (18 Nov 1997) |
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| limbic system | Collective term denoting a heterogeneous array of brain structures at or near the edge (limbus) of the medial wall of the cerebral hemisphere, in particular the hippocampus, amygdala, and fornicate gyrus; the term is often used so as to include also the interconnections of these structures, as well as their connections with the septal area, the hypothalamus, and a medial zone of mesencephalic tegmentum. By way of the latter connections, the limbic system exerts an important influence upon the endocrine and autonomic motor system's; its functions also appear to affect motivational and mood states. Synonym: visceral brain. (05 Mar 2000) |
| linnaean system of nomenclature | The system of nomenclature in which the names of species are composed of two parts, a generic name and a specific epithet (species name, in botany). Synonym: binary nomenclature, binomial nomenclature. Origin: Carl von Linne (05 Mar 2000) |
| lutheran blood-group system | A complex blood group system having pairs of alternate antigens and amorphic genes, but also subject to a dominant independently segregating repressor. (12 Dec 1998) |
| lymphatic system | <anatomy> The tissues and organs (including the bone marrow, spleen, thymus and lymph nodes) that produce and store cells that fight infection and the network of vessels that carry lymph. (12 May 1997) |