When men are sexually stimulated, the reflex centers of the spinal cord begin to emit impulses that move from the cord to the genitals and initiate emission, (the precursor to ejaculation).

 

Fluid from the vas deferens, the prostate, the ampulla, and the seminal vesicles (and even more tiny glands) are sent into the internal urethra by contractions of the groin muscles. This action elicits signals that are transmitted through the pudenda nerves from the spinal cord. Increases in pressure in the urethra cause the semen to be propelled to the exterior, resulting in ejaculation.

 

This phase of emission and ejaculation is termed male orgasm. After ejaculation, erection ceases within 1 to 2 minutes in most males.