The Body Systems Involved in Sexual Arousal and Orgasm
Although the sexual response cycle is laid out as a progression of bodily events, there are actually many different systems working together simultaneously. These systems are intricately woven together, responding to cues and messages sent between them to keep the process of arousal moving along. The body systems involved in sexual arousal and orgasm are the nervous system, the cardiovascular system, the exocrine glands, the muscular-skeletal system, and the endocrine system.
The Involuntary Nervous System
Sexual response is initially triggered by your nervous system perceiving some form of erotic stimulation, either mental or physical. Physical stimulation may be sensations of touch on or near your erogenous zones, be it either the genitals or some other sensitive part of your body. Mental stimulation may come in the form of erotic thoughts or fantasy, or it may involve mentally focusing on your erogenous zones and the possibility of pleasurable sensations there.
The nervous system responds in multiple ways to this sensory or mental input. The neural impulses communicate with all the other systems in the body. The brain tells certain hormones to begin flowing, certain muscles to begin tightening, and certain glands to begin secreting. Most of this communication is involuntary, like a reflex, and not in your direct control.
The stages of the sexual response cycle involve a steadily increasing activation of the sympathetic nervous system. This involuntary part of the nervous system is what prepares a person for intense activity. Activation of the sympathetic nervous system increases heart rate, breathing rate, blood pressure, and muscular tension, among other effects.
The counterpart of the sympathetic nervous system is the parasympathetic nervous system. The parasympathetic nervous system prepares the body for rest and relaxation. It slows the heart rate and breathing rate and decreases blood pressure and muscle tension.
Feedback Loops
Several body systems engage in positive feedback loops as sexual excitement increases. One example of this is vasoconstriction. The brain, in response to some initial stimulation, may tell the cardiovascular system to restrict blood flow out of the genital area. The brain then senses the resulting engorgement as a new source of sexual stimulation. This induces it to direct the veins to constrict even further to maximize the engorgement of sexual tissue.
Fact
The main nerves that service the pelvic region and sexual organs are the pudenal nerves, the pelvic nerves, the hypogastric nerves, and the vagus nerves. The pudenal nerves are believed to be the main nerves responsible in carrying out the arousal and orgasm messages to and from the brain. They service both the clitoris and the penis.
The intensity of orgasm is partly a result of the dramatic shift in the nervous system that occurs during orgasm. Suddenly, the sympathetic nervous system is deactivated and the parasympathetic nervous system is triggered. Such a dramatic shift in the nervous system results in some of the extraordinary sensations associated with orgasm: simultaneous excitement and release. It also accounts for the peaceful states people often experience after orgasm.
Another example of a positive feedback loop involves the muscular-skeletal system. Initial stages of arousal result in subtle muscle contractions in the pelvic area. The increased muscular activity heightens sensation in the pelvis, which then feeds the brain with a wealth of sensory stimulation, which in turn focuses the brain on the body and away from distracting thoughts. This increasing stream of sensory input to the nervous system helps create the cascading effect of increasing arousal, potentially leading to orgasm.
Finally, the endocrine system and the nervous system interact in positive feedback loops as well. Researchers have not yet uncovered all the details of the interplay between hormones and the brain, but they do know that certain hormones can increase or decrease the threshold for the excitation of nerves. Thus, the hormones that the brain directs the gonads (the ovaries and testes) to release end up affecting the type of information the brain subsequently receives. In other words, sexual stimulation results in the release of hormones that keep the brain even more focused on sex.
When you have sex, there's a lot going on behind the scenes. The specific sexual organs are each doing their job. The larger systems of your body are interacting with each other. Each sensation or event builds on the previous ones in a response cycle that may ultimately lead to orgasm. While many of the details of these bodily functions are not consciously directed, it can be helpful to understand the whole picture. Your body is an amazing and complex instrument, inherently capable of great pleasure.
