The seminiferous tubules contain another type of cell called Sertoli cells. These are relatively large elements extending from the basement membrane towards the lumen. They are regarded as supporting cells, which probably provide nourishment for the spermatids. In some species, the sperm heads remain embedded in the Sertoli cells for relatively long periods. The release of spermatozoa from the Sertoli cells is termed spermiation, a process that is analogous to ovulation in the female.
Figure: Diagrammatic section through a mammalian seminiferous tubule showing Sertoli cell and a mobile population of differentiating germ cells