testes

The testes serve three main functions:

1- Production of gametes.

2- Secretion of hormones that cause differentiation of the brain and reproductive tract during fetal and neonatal development, maintain the structure and function of the reproductive tract, it promotes the development of sexual characteristics.

3- Feedback regulation of the hypothalamus –pituitary hormones secretion.

The seminiferous tubules are lined with sertoli cells and the spermatogonia. The sertoli cells are linked by tight junctional complexes to form the sertoli cells barrier which limits the movement of fluid and nutrients between interstitial space of the testis and the lumen of seminiferous tubules, lipid soluble substances such as steroids (androgen) are able to traverse the barrier and enter the lumen of the seminiferous tubules, the barrier prevent the penetration of immunoglobulin that might interfere with the development of spermatozoa.