Spermatogenese

Spermatogenesis begins at puberty and continues late into life, producing sperm in the seminiferous tubules.

It has three main stages — mitosis, meiosis, and spermiogenesis.

During mitosis, the spermatogonia or stem cells divide to produce two identical daughter cells.

The type-A spermatogonium remains in contact with the basement membrane of the seminiferous tubule, maintaining the stem cell population.

The type-B spermatogonium, displaced toward the lumen, forms a primary spermatocyte that enters meiosis.

During meiosis I, homologous chromosomes in each primary spermatocyte pair up and exchange genetic material to form two daughter cells called secondary spermatocytes, each with half the number of chromosomes.

After meiosis II, the four resultant haploid cells are called spermatids.

During the final stage — spermiogenesis — these spermatids undergo a series of transformations to become mature, functional sperm.

Nurse cells, also known as Sertoli cells, provide nutrients and support to the developing sperm cells. They regulate the hormones and environment within the seminiferous tubules throughout spermatogenesis.