Sperm
A sperm cell, or spermatozoon, is the haploid cell that is the male gamete. It is carried in fluid called semen, and is capable of fertilising an egg cell to form a zygote. A zygote can grow into a new organism, such as a human. Sperm cells contain half of the genetic information needed to create life. Generally, the sex of the offspring is determined by the sperm with the chromosomal pairs "XX" and "XY". Sperm cells were first observed by Antoni van Leeuwenhoek in 1679.
Sperm structure and size
Individual spermatozoa are highly differentiated cells, composed normally of a head, basal body (or midpiece), and tail. The head contains some cytoplasm and the nuclear material for fertilization. The basal body contains a large concentration of mitochondria that provide the energy for sperm motility through the production of ATP. The spermatozoan tail is typically a flagellum used for propulsion.
In humans, sperm cells consists of a head 5 µm by 3 µm and a tail 50 µm long. The tail flagellates, which propels the sperm cell. The cell is characterized by a minimum of cytoplasm.
Sperm production
Main article: Spermatogenesis
Sperm are produced in the seminiferous tubules of the testes in a process called spermatogenesis. Round cells called spermatogonia divide and differentiate eventually to become sperm. During sexual intercourse the sperm is deposited in the vagina - and then it moves to the ovum.
de:Spermium es:Espermatozoide fr:Spermatozoïde nl:Sperma ja:精子 lt:Spermatozoidas pl:Plemnik ru:Сперматозоид