THE PARASYMPATHETIC NERVOUS SYSTEM brings the body back to its normal relaxed condition and restores vital energy. It is like the brake of a car that brings to a halt the accelerating automobile—the human engine. The accelerator and brake of a car are under the conscious control of the driver but, unfortunately, in human beings the autonomic nervous system is not under our conscious control.
The parasympathetic nerves bring about rest, relaxation and recuperation. They are the nerves of pleasure, erection and copulation. The parasympathetic fibres originate in the second and third sacral vertebrae of the spinal cord to form a single nerve on each side—called the NERVIERIGENTES. Stimulation of the nervierigentes leads to dilation of arterioles (minute arteries) and filling up of the cavernous spaces with blood, producing erection of the penis.
The penis receives a double nerve supply from the spinal nerves as well as from the autonomic nervous system. The spinal supply conveys the sensations of touch, pain and heat from the skin of the penis to the sensory centre in the brain (thalamus). The pleasant sensations produced by arousal and erection of your penis when your partner caresses your organ are conveyed by the spinal nerves to the brain via the spinal cord. If brief, while stimulation of the parasympathetic (nervi erigentes) causes erection, stimulation of the sympathetic nerves (hypogastric) causes ejaculation and subsequent loss of erection, due to contraction of the arterioles and decrease in the blood supply to the penis.
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Men's Health-Erectile Dysfunction
