The cell which forms blood-testis barrier is
**Core Concept**
The blood-testis barrier is a unique structural and functional barrier in the seminiferous tubules of the testis, crucial for the proper development and maturation of sperm cells. It is formed by tight junctions between Sertoli cells, which separates the seminiferous tubules from the bloodstream.
**Why the Correct Answer is Right**
The Sertoli cells play a pivotal role in forming the blood-testis barrier, which maintains the immune-privileged status of the testis. This barrier prevents the immune system from recognizing and attacking the developing sperm cells, which are otherwise foreign to the body. The Sertoli cells also provide nutritional support and regulate the development of sperm cells through their interaction with germ cells. The tight junctions between Sertoli cells are composed of occludin and claudin proteins, which are critical for maintaining the integrity of the blood-testis barrier.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the Leydig cells are responsible for testosterone production, not forming the blood-testis barrier.
**Option B:** This option is incorrect because the peritubular cells are involved in the contraction of the seminiferous tubules, but they do not form the blood-testis barrier.
**Option C:** This option is incorrect because the germ cells are the precursors to sperm cells, but they do not form the blood-testis barrier.
**Clinical Pearl / High-Yield Fact**
The blood-testis barrier is essential for maintaining the fertility of males, as it prevents the immune system from attacking developing sperm cells. Any damage to this barrier can lead to autoimmune reactions against sperm cells, resulting in infertility.
**Correct Answer:** C. Sertoli cells.