The male reproductive system includes the scrotum, testes, spermatic ducts, sex glands, and penis. These organs work together to produce sperm, the male gamete, and the other components of semen. These organs also work together to deliver semen out of the body and into the vagina where it can fertilize egg cells to produce offspring. Testis has many seminiferous tubules. Each seminiferous tubule has many layers of cells at different stages of spermatogenesis. From outer to inner, the cells are spermatogonia, primary and secondary spermatocytes, spermatids and sperms. Prostate gland is an exocrine gland, which secretes prostatic fluid.