Orgasms and Nerves
Without nerves sending impulses back to the spinal cord and brain, an orgasm wouldn't be possible. Just like any other area of the body, the genitalia contain different nerves that send information to the brain to tell it about the sensation that's being experienced. This helps to explain why the sensations are perceived differently depending on where someone is being touched. A clitoral orgasm, for example, differs from a vaginal orgasm because different sets of nerves are involved.
All of the genitalia contain a huge number of nerve endings (the clitoris alone has more than 8,000 of them), which are, in turn, connected to large nerves that run up through the body to the spinal cord. (The exception is the vagus nerve, which bypasses the spinal cord.) They perform many other functions in the body in addition to providing the nerve supply, and therefore feedback to the brain, during sexual stimulation. Here are the nerves and their corresponding genital areas
- hypogastric nerve - transmits from the uterus and the cervix in women and from the prostate in men
- pelvic nerve - transmits from the vagina and cervix in women and from the rectum in both sexes
- pudendal nerve - transmits from the clitoris in women and from the scrotum and penis in men
- vagus nerve - transmits from the cervix, uterus and vagina
The role of the vagus nerve in orgasms is a new discovery and there's still much that's unknown about it; until recently, researchers didn't know that it passed through the pelvic region at all.
Since most of those nerves are associated with the spinal cord, it would stand to reason that a person with a severed spinal cord wouldn't be able to have an orgasm. And for a very long time, that's what people with these types of injuries were told. However, recent studies show that people with spinal cord injuries -- even parapalegics -- can reach orgasm. Dr. Barry Komisaruk and Dr. Beverly Whipple of Rutgers University conducted a study on women with severed spinal cords in 2004. They discovered that these women could feel stimulation of their cervixes and even reach orgasm, although there was no way their brain could be receiving information from the hypogastric or pelvic nerves. How was this possible? An MRI scan of the women's brains showed that the region corresponding to signals from the vagus nerve was active. Because the vagus bypasses the spinal cord, the women were still able to feel cervical stimulation.
So during sexual stimulation and orgasm, different areas of the brain receive all of this information that lets it know exactly what's happening -- and that what's happening is very enjoyable. But until recently, we had no way of knowing exactly what was happening in the brain at the exact moment of orgasm. We'll check out the latest research next.