31.7 : Sperm Transport

The journey of sperm from its origin to the point of ejaculation begins within the seminiferous tubules of the testis. Here, Sertoli cells produce fluid that propels non-motile sperm through a series of conduits, starting with the straight tubules leading to the rete testis. This interconnected network of tubules acts as the initial pathway for sperm, guiding them into the efferent ductules and then into the epididymis for maturation.

The maturation phase occurs in the epididymis, where sperm spend two to three weeks gaining the motility and maturity necessary for fertilization. This transformation is crucial for the sperm's ability to fertilize an ovum. As they transit through the epididymis, peristaltic contractions facilitate the movement of mature sperm into the vas deferens, where they enter a state of temporary inactivity. The absence of triggers for ejaculation allows sperm to be stored within the epididymis and vas deferens for extended periods, sometimes for months, without losing their fertilizing potential.

During ejaculation, peristaltic contractions in the vas deferens propel stored sperm toward the ejaculatory ducts, driven by stimulation from the sympathetic nervous system. The sperm and fluids from the accessory glands are expelled from the body through the urethra in a process called ejaculation.