The epithelium of seminiferous tubule is made up of two types of cells-Sertoli cells and spermatogenic cells. Sertoli cells are elongated and pyramidal which partially envelope the spermatogenic cells. These nourish spermatozoa, act as nurse cells for differentiating spermatozoa. These secrete a glycoprotein hormone, called inhibin which is involved in the negative feed back control of sperm production.