11. Through this hormonal disruption, the process of sperm production in the seminiferous tubules is reduced. 12. It is secreted from the Sertoli cells, located in the seminiferous tubules inside the testes. 13. This absorption creates a fluid current that moves the immobile sperm from the seminiferous tubules to the epididymis. 14. The higher levels of these hormones enable spermatogenesis in the seminiferous tubules and sperm maturation in the epididymis. 15. This is overcome at puberty when cells within seminiferous tubules called Sertoli cells start making their own retinoic acid. 16. Each lobule contains the seminiferous tubules , extending from the base where they end blindly, towards the apex. 17. The testicles converge to form the seminiferous tubules , coiled tubes at the top and back of each testicle. 18. Spermatogonia stem cells in mammals are found between the basal membrane of the seminiferous tubules and the Sertoli cells. 19. They secrete testis-determining factor, a binding protein which increases the concentration of testosterone inside the seminiferous tubules . 20. The ampullae are otherwise essentially identical to the seminiferous tubules in higher vertebrates, including the same range of cell types.
