In spermatogenesis, Sertoli cells provide an essential support function including the blood-testis barrier. Which intercellular junction type forms the blood-testis barrier and what is its functional significance?
- A Gap junctions between Sertoli cells and spermatocytes; facilitate metabolic coupling and enable coordinated differentiation
- B Desmosomes between Sertoli cells and peritubular myoid cells; provide mechanical strength to the seminiferous tubule wall
- C Hemidesmosomes between Sertoli cells and the basement membrane; maintain tubular architecture and prevent extrusion of spermatocytes
- D Tight junctions (occluding junctions) between adjacent Sertoli cells; segregate the adluminal compartment from the basal compartment, protecting haploid germ cells from immune surveillance and providing a specialised microenvironment ✓
Explanation
The blood-testis barrier is formed by specialised tight junctions (ectoplasmic specialisations containing ZO-1, claudin-3, claudin-11, and occludin) between adjacent Sertoli cells. These junctions divide the seminiferous epithelium into a basal compartment (containing spermatogonia and preleptotene spermatocytes) accessible to blood-borne molecules, and an adluminal compartment isolated from the immune system. Haploid spermatids and late spermatocytes express unique surface proteins that would be recognised as 'non-self' — the barrier prevents autoimmune orchitis. Disruption of tight junctions (e.g., by gossypol) impairs spermatogenesis and causes infertility.
Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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