Physiology of Sex

1. What part of the autonomic nervous system controls erection and ejaculation?
2. What are the afferent and efferent limbs of the erection reflex?
3. What is the role of nitric oxide?
4. Where do the sympathetic nerves regulating ejaculation originate?
5. What is the effect of parasympathetic nerves in causing female stimulation?

Answers:
1. Erection is controlled by the parasympathetics, ejaculation by the sympathetics.
2. The afferent limb is somatic fibers from the genitals through the pudendal nerve into the spinal cord. The efferent limb is parasympathetic fibers that start in the sacral spinal cord and travel through the cauda equina and exit through S2-4 nerve roots, secreting nitric oxide.
3. Nitric oxide causes relaxation of smooth muscle of corpus cavernosum and increases blood flow to the penile arteries.
4. Fibers originate in T12-L2 and travel through the hypogastric plexus.
5. Dilation of arteries to perineal muscles and tightening of the introitus, secretion of mucus by Bartholin's glands.