Or semen; The fluid containing the male gametes (sperm cells) of animals. Usually, each sperm cell has a head capsule containing a nucleus, a middle portion containing mitochondria (which provide energy), and a long tail (flagellum).
In most animals, sperm cells (sometimes called “sperm” for short) are motile, and are propelled by a long flagellum, but in some (such as crabs and lobsters) they are nonmotile. The term is sometimes used for the motile male gametes (antherozoids) of lower plants. The human sperm is 0.005 mm long and can survives inside the female for 2–9 days.
Sperm counts have fallen by 50% worldwide since 1940, according to a Danish study 1990. This reduction may be due to increases in pollution as a number of pollutants, including some petroleum by-products and polychlorinated biphenyls, mimic the effects of the female hormone estrogen on cells.
The male reproductive cell; the male gamete; SYN. sperm cell, spermatozoon.
1. zool. Životinjsko i čovečje seme, gusta i beličasta semena tečnost spolno zrelih mužjaka koju pri snošaju izbacuje ud i koji sadrži spermatozoe;
2. bot. Seme.