The spermatozoon or sperm is a mobile male cell. It can reach a length of 0.05 millimeters. Its function is to achieve fertilization by binding with the female cell called ovum. A sperm has three parts:
– Head: it contains a nucleus that carries genetic material in the form of chromosomes packed with DNA. This material will determine the sex of the offspring, among other traits. It also carries an acrosome, a cap-like structure that enables the sperm to soften the coating of the ovum in order to penetrate it, thus achieving fertilization. It also has a small amount of cytoplasm wrapped in a plasma membrane that connects it to the neck.
– Neck or middle piece: it contains a large amount of organelles called mitochondria, which release the energy the sperm needs to swim on its journey towards the ovum.
– Tail: its only function is to shake in order to propel the sperm towards the ovum, reaching a speed of about 3 to 3.5 mm a minute.
Sperm production needs to take place at a temperature of around three degrees centigrade above normal body temperature. They are produced in the seminiferous tubules at a rate of 10,000 to 30,000 million per month. Afterwards, the newly formed cell passes on to the epididymis, where it needs between 60 to 72 hours to reach full maturity.