Sertoli cells: Structure and Function

Sertoli cells, also known as sustentacular cells, are a type of somatic cell found within the seminiferous tubules of the testes. They play a critical role in the development and maintenance of the testes, as well as in the process of spermatogenesis (sperm production).

Structure of Sertoli Cells

Sertoli cells are elongated cells that span the entire width of the seminiferous tubules. They are characterized by their tall columnar shape and possess numerous branching processes that extend from their basal surface towards the lumen of the tubules. These processes form tight junctions with adjacent Sertoli cells, creating a barrier that separates the tubules into two compartments: the basal compartment, which contains spermatogonia (sperm precursor cells), and the adluminal compartment, which houses the maturing germ cells.

Functions of Sertoli Cells

1. Support and Protection: Sertoli cells provide structural support to the developing germ cells within the seminiferous tubules. They also form a protective barrier, called the blood-testis barrier, which prevents the immune system from attacking the developing spermatozoa.

2. Spermatogenesis: Sertoli cells play a crucial role in the process of spermatogenesis. They provide a nurturing environment for the developing germ cells by secreting a variety of growth factors and hormones. These factors support the proliferation, differentiation, and maturation of the germ cells into spermatozoa.

3. Nutrient and Waste Exchange: Sertoli cells facilitate the exchange of nutrients and waste products between the blood vessels in the tubule walls and the developing germ cells. They selectively transport essential nutrients such as glucose and amino acids from the blood into the adluminal compartment, ensuring proper nourishment for the developing spermatozoa. Additionally, they remove metabolic waste products from the adluminal compartment and transport them back into the bloodstream for disposal.

4. Hormone Secretion: Sertoli cells secrete various hormones and growth factors that regulate the function of the testes. These include anti-Müllerian hormone (AMH), which inhibits the development of female reproductive structures, and androgen-binding protein (ABP), which binds to testosterone and helps maintain high concentrations of this hormone within the seminiferous tubules.

In summary, Sertoli cells are essential for the support, protection, and nourishment of developing germ cells within the testes. They play a crucial role in spermatogenesis and ensure the proper functioning of the male reproductive system.