Spermatogenesis takes place in the wall of the seminiferous tubules, with stem cells at the tube's perimeter and spermatozoa at the tube's lumen. Diploid, undifferentiated cells are seen immediately under the tubule's capsule.
Spermatogonia (singular: spermatagonium) are stem cells that go through mitosis, with one offspring becoming a sperm cell and the other giving rise to the next generation of sperm. The process of meiosis starts with a cell known as a primordial spermatocyte.
A haploid cell known as a secondary spermatocyte is formed at the end of the first meiotic cycle. This haploid cell must divide again during meiosis. A spermatid is a cell that is formed at the completion of meiosis.
A sperm cell is defined as a cell that reaches the lumen of the tubule and develops a flagellum (or "tail"). Each meiotic primary spermatocyte produces four sperm. During pregnancy, stem cells are deposited and are present from birth until the beginning of puberty, although they are dormant.
Gonadotropic hormones from the anterior pituitary stimulate the activation of these cells and the production of viable sperm during adolescence. This is something that endures into old age.
Below is a diagrammatic representation of Spermatogenesis:-