21. Physiology of reproduction. Male reproductive system. Spermatogenesis. Male sex hor-mones (androgens) – types, physiologic effects and control of secretion. Erection and ejacu-lation.

Male reproductive system. Endocrine function of the testes and its Control. Spermatogenesis.

The male reproductive system is responsible for producing and delivering sperm and synthesizing and secreting testosterone. Its key components include the testes, epididymis, vas deferens, seminal vesicles, prostate gland, and urethra.

Endocrine Function of the Testes

The testes are the male gonads, located in the scrotum outside the body cavity to maintain a lower temperature (35°C–36°C) essential for spermatogenesis. They have two primary functions:

1. Spermatogenesis: The production of sperm within the seminiferous tubules.
2. Hormone secretion: Primarily testosterone, synthesized by the Leydig cells, which are interspersed between the seminiferous tubules.

The tests contain 2 groups of cells:

• ♦ Germinal cells, they give rise to the sperm cells.
• ♦ Somatic cells, here are 3 main cell types.
• Sertoli cells, they act in a supportive role for germ cells and also produce:

• Produce müllerian-inhibiting substance.
• Act in supportive role for germ cells.
• They form the blood-testis barrier.
• Produce androgen-binding protein.
• Produce inhibin (inhibits FSH). Produce seminiferous tubule fluid.
• Leydig cells, they produce testosterone (when stimulated by LH).