Samenkanälchen

Samenkanälchen, also known as seminiferous tubules, are coiled tubes found within the testes of male vertebrates. These microscopic structures are the primary sites of spermatogenesis, the process of sperm production. Each testis contains hundreds of such tubules, which collectively form the bulk of the testicular tissue.

The walls of the samenkanälchen are composed of several layers of cells. The outermost layer is a basement membrane, followed by several layers of myoid cells. The inner lining of the tubules consists of a germinal epithelium. This epithelium contains two main types of cells: spermatogonia, which are the stem cells that divide to produce sperm, and Sertoli cells. Sertoli cells are large, supportive cells that nourish and protect the developing sperm cells, play a role in regulating spermatogenesis, and form the blood-testis barrier.

As spermatogonia undergo meiosis and differentiate, they mature into spermatozoa. This process takes approximately 74 days in humans. The developing sperm cells are embedded within the cytoplasm of the Sertoli cells and move towards the lumen of the tubule as they mature. Once they reach the lumen, they are released and then travel through a network of ducts to the epididymis for further maturation and storage. Interstitial cells, also known as Leydig cells, are located in the connective tissue between the samenkanälchen and are responsible for producing testosterone.