Ejaculation

Ejaculation moves semen through and out of the urethra. In male reproductive physiology, emission brings sperm and glandular fluids into the urethra, while expulsion uses coordinated muscular contractions to discharge them. Contributions from the autonomic nervous system and somatic nervous system couple secretion and transport with the activity of skeletal muscles.

The coordination involves the spinal cord, rather than being an isolated contraction of one reproductive organ. A rat experiment identified a population of spinal neurons whose loss disrupted ejaculation while leaving other components of mating behavior relatively preserved.^[ref] The result supports a spinal cord coordinating mechanism in that animal model; it does not by itself establish that every aspect of human ejaculation or sexual experience has the same organization of the nervous system.