Blood testis barrier are present in

A. i.e. (Sertoli cells) (424- Ganong 22nd) (403 - Ganong 23rd)* Tight junctions between adjacent sertoli cells near the basal lamina form a blood -testis barrier* It prevents the entry of many substances from testicular interstitium into the lumen of seminiferous tubules* Functions of sertoli cells1. Support and nourish the germ cells till the spermatozoa are released from them2. Provide hormonal and other substances necessary from spermatogenesis3. Convert androgens into estrogen4. Secrete - androgen binding protein (ABP)**, Inhibin** Mullerian regression factor (MRF), Mullerian inhbiting substance (MIS)Blood testis barrier helps maintaining the composition of the fluid in the lumen of the seminiferous tubules and also protects the germ cells from blood borne noxious agentsIt also prevents antigenic products of germ cell division from entering the circulation and generating an autoimmune responseIt contains high concentration of androgens, oestrogens, K+, inositol glutamic and aspartic acid with low content of protein and glucose (808 - A.K. Jain 3rd)