Mannelijke seksuele reactie: erectie en ejaculatie

In response to the sexual stimuli, the parasympathetic neurons stimulate the local release of nitric oxide, or NO, dilating the arterioles in the penis. This increases blood flow into the erectile tissues — the corpora cavernosa and corpus spongiosum.

The blood filling the erectile tissues compresses the veins to prevent blood from leaving the penis.

As a result, the penis becomes engorged and rigid, leading to an erection.

At the critical point of sexual arousal, a spinal reflex coordinated by the sympathetic fibers in the lumbar region triggers ejaculation.

This reflex causes coordinated contractions of the epididymis, vasa deferens, seminal vesicles, and prostate gland, propelling semen into the prostatic urethra.

After the semen enters the penis, muscles like the bulbospongiosus and the ischiocavernosus in the pelvic floor contract.

These contractions of the ducts, glands, and muscles forcefully expel semen from the urethra to the exterior in a process called ejaculation.