Spermatozoan (SmTbs)

The spermatozoan is a fully mature male gamete, that is motile, and serves to fertilize the ovum.  The spermatozoan has a characteristic structure:  an oval-shaped head, which contains the nucleus and the acrosome, a granular vesicle that encases the top of the nucleus and contains hydrolytic enzymes required for penetration into the oocyte during fertilization, the midpiece, which contains a prominent array of mitochondria, which are required to produce ATP; a tail (flagellum) composed of a core of microtubules, whose sliding is powered by flagellar dynein. Microtubules, associated motor and linker proteins are called axoneme.