In between the Sertoli cells are spermatogenic cells, which differentiate through meiosis to sperm cells. Sertoli cells function to nourish the developing sperm cells. They secrete testis-determining factor, a binding protein which increases the concentration of testosterone inside the seminiferous tubules. Embryologically, they also secrete the anti-Müllerian hormone (AMH) necessary for the female Müllerian ducts to regress.
There are two types: convoluted and straight, convoluted toward the lateral side, and straight as the tubule comes medially to form ducts that will exit the testis.
The seminiferous tubules are formed from the testis cords that develop from the primitive gonadal cords, formed from the gonadal ridge.