Question

What is the function of Sertoli cells in human testes?

Hint:

Sertoli cells are often referred to as "nurse cells" because they support and regulate the process of sperm production and maturation in the testes.

Answer 1

Sertoli cells, also known as "nurse cells," are specialized cells found in the seminiferous tubules of the testes. These cells are essential for the process of spermatogenesis, which is the production of sperm. Their functions include the following:
1. Support and nourishment of developing sperm cells:
Sertoli cells provide physical support and nourishment to the developing spermatozoa throughout spermatogenesis. They provide a conducive environment for the growth and maturation of sperm cells from spermatogonia (stem cells) to mature spermatozoa.
2. Formation of the Blood-Testis Barrier:
Sertoli cells create the blood-testis barrier, a specialized structure that prevents harmful substances and immune cells from accessing the developing sperm cells. This barrier is formed by tight junctions between adjacent Sertoli cells, ensuring that only necessary substances reach the sperm cells. It also protects sperm from immune system attack, as sperm cells are genetically different from the body and could be recognized as foreign invaders.
3. Secretion of Hormones:
Sertoli cells secrete various hormones and proteins essential for the regulation of spermatogenesis. One of the key hormones secreted is Inhibin, which regulates the production of Follicle Stimulating Hormone (FSH) by the pituitary gland, thereby controlling the rate of spermatogenesis. They also secrete androgen-binding protein (ABP), which binds to testosterone, ensuring that the testosterone concentration remains high within the seminiferous tubules, further supporting sperm maturation.
4. Phagocytosis of Residual Cytoplasm:
During spermatogenesis, as the spermatid transforms into a mature spermatozoon, excess cytoplasm is eliminated. Sertoli cells play a crucial role in phagocytizing (engulfing and digesting) this excess cytoplasm, ensuring the formation of a compact and mature sperm cell.
5. Regulation of Spermatogenesis:
Sertoli cells also help regulate the process of spermatogenesis by responding to hormonal signals from the pituitary and hypothalamus. They communicate with germ cells through paracrine signaling to support their development.