Sperm

Sperm (精子) (also known as spermatozoa) are the male reproductive cells, or gametes. Their name is derived from the Greek word σπέρμα sperma, meaning "seed".

In the types of sexual reproduction known as anisogamy and its subtype oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell.

Appearance
The sperm cells look like swimmers; with a swimsuit consisting of a swim cap, a large bulbous "head" surrounding the body, and a tail piece trailing behind.

Their immature spermatogonia forms are depicted as infants being raised by Sertoli cell nurses in a nursery.