Spermatozoa, or male gametes, are small, mothie cells (capable of movement). They carry the hereditary information from the father.
-The head, which contains the cell nucleus with the hereditary material
-A mid-piece, the many mitochondria of which generate the enrgy required for movement.
-The tail, which is called flagellum, enables them to move.
THE FORMATION OF SPERMATOZOA
The formation of spermatozoa, takes place in the seminiferous tubules, which include the interstitial cells that segretate testosterone. The walls of these tubules contain cells called germ cells, which are constantly multiplying themselves. As they multiply, the cells move towards the end of the tube and gradually mature until they become spermatozoa. The process is initiated at pubery by the action of male hormones and continues throughout the rest of the individual´s life.
Ova, or female gametes, are large, spherical, immobile cells which contain the hereditary information from the mother.
-The nucleus, which contains the hereditary information.
-The cytoplasm, which contains nutritional substances, and three membranes: the vitaline membrane, the zona pellucida and the corona radiata.
-Stage one. Female develop immature ova when they are still embros inside their mother´s womb. These ova are surronded by other cells to make structures known as follicles. The follicles, with the inmature ova inside, then stop developing until the woman reaches puberty.
-Stage two. This stafe occurs after the onset of puberty and takes place in cycles of approximately 28 days. The follicle grows and the ovum inside matures and leaves the ovary; this process is known as ovulation. Women ovulate more or less once a month, from puberty until menopause