SOURCE: Wellcome Images, B0007805 Sperm cell
Digital artwork/Computer graphic by Anna Tanczos
THE STRUCTURE OF A SPERM CELL
The male gamete
Each single spermatozoan (plural spermatozoa) contains a haploid number of chromosomes (one copy of each) in the nucleus situated in the head region.
Surrounding the head of the sperm cell is the acrosome cap [shown in blue] - this contains special enzymes that digest the zona pellucida (the membrane surrounding the egg cell) to assist in fertilization.
The mid piece of the sperm cell contains two centrosomes [in green] and coiled mitochondria [gold]. The sperm will contribute both centrosomes to the embryo upon fertilization, which are essential for organising microtubules and thus subsequent cell divisions of the embryo.
The large coiled mitochondria [gold] provide the sperm with the energy supplied to the long flagella (or tail) required for it motility.