Question

Sertoli cells are found in
A. Seminiferous tubule
B. Germinal epithelium
C. Cauda epididymis
D. Caput epididymis

Answer 1

Hint: A Sertoli cell (a kind of sustentacular cell) is a "nurse" cell of the testicles. The Sertoli cell is activated by follicle-stimulating hormone (FSH) secreted by the adenohypophysis and has FSH receptors on its membranes.

Complete answer:
The Sertoli cell is specifically located in the convoluted seminiferous tubules. Seminiferous tubules are the only place in the testes where the spermatozoa are produced. The development of Sertoli cells is directed by the testis-determining factor protein. Sertoli cells help in the process of spermatogenesis, the production of sperm. Sertoli cells are required for male sexual development. During male development, the gene SRY activates SOX9, which then activates and forms a feedforward loop with FGF9. Sertoli cell proliferation and differentiation are mainly activated by FGF9. The absence of FGF9 tends to cause a female to develop female characteristics. Once fully differentiated, the Sertoli cell has been considered to be terminally differentiated and is unable to proliferate.
Therefore, once spermatogenesis has begun, no more Sertoli cells are created.
So, the answer is A. Seminiferous tubule

Note: Sertoli cells secrete the following:
1. Anti-Müllerian hormone (AMH) — It is secreted during the early stages of fetal life.
2. Inhibin and activins — It is secreted after puberty, and works together to regulate FSH secretion.
3. Androgen binding protein (also called testosterone binding globulin) — It increases testosterone concentration in the seminiferous tubules to slightly stimulating spermatogenesis.
4. Estradiol — It is aromatase from Sertoli cells. It converts testosterone to 17-beta estradiol to direct spermatogenesis.
5. ETS Related Molecule or ERM transcription factor — It is needed for the maintenance of the spermatogonial stem cell in the adult testis.
6. Transferrin — It is a blood plasma protein for iron ion delivery.
7. Testicular ceruloplasmin — It is a ceruloplasmin-like protein that is immunologically similar to serum ceruloplasmin.