Explain the roles of the parasympathetic and sympathetic nervous systems in the basic phases of the male sexual response, erection and ejaculation
What will be an ideal response?
Although erection is under parasympathetic control, ejaculation is under sympathetic control. During sexual arousal, a parasympathetic reflex triggers the release of nitric oxide (NO) from blood vessel endothelial cells. This relaxes smooth muscle in the walls of the arterioles of the penis, dilating them, and within the blood sinuses in erectile tissue, which allows large amounts of blood to enter the tissue. The combination of increased blood flow and widening blood sinuses results in an erection. Ejaculation, the process by which semen is expelled from the penis, actually occurs in two stages, emission and expulsion. Emission is the movement of sperm and testicular fluid, as well as secretions from the prostate and seminal vesicle, into the urethra. Rhythmic contractions of skeletal muscles at the base of the erectile columns of the penis result in the expulsion of semen from the urethra.
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What will be an ideal response?
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