trophic, a. (n.)
(ˈtrɒfɪk)
[ad. Gr. τροϕικός, f. τροϕή nourishment: see -ic. Cf. F. trophique.]
A. adj.
1. Biol. a. Of or pertaining to nutrition; spec. of certain nerves and nerve-centres, Concerned with or regulating the nutrition of the tissues.
| 1873 A. Flint Physiol. Man, Nervous Syst. ii. 80 Centres attached to the sensory system of nerves, which have, as far as we know, a purely trophic influence over the nerves. 1875 H. C. Wood Therap. (1879) 559 Nerves which preside over nutrition,—the so-called trophic nerves. 1894 Lancet 3 Nov. 1030 The large amount of wasting of the muscles..might suggest the possibility of a trophic lesion. 1899 Allbutt's Syst. Med. VII. 124 Another affection of the lower limbs, possibly trophic,..is rupture of the tendo Achillis. |
b. Ecol. Of or pertaining to the feeding habits of, and the food relationship between, different types of organisms in the food-cycle; so trophic level, any of a hierarchy of levels of an ecosystem, each consisting of organisms sharing the same function in the food-web, and the same relationship to the primary producers.
| 1942 Ecology XXIII. 407/2 Food-cycles rarely have more than five trophic levels. 1957 Ecol. Monogr. XXVII. 55 (heading) Trophic structure and productivity of Silver Springs, Florida. 1974 R. H. Britton in R. Goodier Natural Environment of Shetland 123 The nutrient poor categories (dystrophic and oligotrophic) are by far the most numerous and..eutrophic and brackish lochs are rather rare... The lochs within each trophic category can be further subdivided according to their superficial area. 1976 Nature 22 July 284/1 The trophic base of the arthropod fauna is wind-blown detritus. 1980 Jrnl. R. Soc. Arts Feb. 140/2 While they are trophic levels—top carnivore, herbivore, plants, microorganisms—none is dominant. |
2. Of a hormone: stimulating the production of another hormone from a specific gland; = tropic a. 4 b.
| 1945 I. S. Kleiner Human Biochem. xxiii. 503 Another hormone of this gland which produces its effect by influencing a different structure, i.e., a ‘trophic’ hormone, is the adrenotrophic factor. 1965 Lee & Knowles Animal Hormones ii. 19 The site of production of the trophic hormone controlling the adrenal cortex is still in doubt. 1975 Nature 27 Nov. 340/2 The existence of a human cell line showing severalfold stimulation by androgens in a defined system, free from the effects of other trophic hormones, should provide a useful reagent for the further study of the mechanism of androgen action. |
B. n. Biol. Something that promotes nutrition.
| 1893 E. S. D'Odiardi Med. Electricity 54 The second class is composed of trophics, or nutrients, i.e., promoters of nutrition. |
So ˈtrophical a. (rare) = trophic adj.; hence ˈtrophically adv., in relation to nutrition.
| 1857 Dunglison Med. Lex., Trophical Nerves, the organic nerves, or nerves of the sympathetic system. 1900 Lancet 23 June 1779/2 This..implies continuity of the protoplasm of one neurone with another, but trophically and genetically the two are independent. |