The Science of Orgasms Part 1 -The Male Orgasm

We’ve all heard of or, if we’re lucky, experienced the magic of a really good orgasm. But what is actually going on in our bodies when we climax? In this series, we’ll explore the physiology of orgasms in both men and women. By understanding what’s happening at a cellular level, we can gain a greater appreciation of the complexity of what is required to achieve sexual satisfaction.

The male orgasm is relatively straightforward. But first, we must talk about what happens in the process of achieving an erection. When a man is aroused, the autonomic nervous system is activated. This is the part of our nervous system that we don’t have voluntary control over. An image, scent, or touch can all be inciting factors. Then the erection cascade begins.

First, neurons in the part of the brain called the hypothalamus become activated by a neurohormone called oxytocin and another neurotransmitter dopamine. These excited neurons send their arousal messages into the lower part of the spinal cord and communicate with other autonomic (non-voluntary) nerves in an anatomic area known as the pelvic plexus. From there, pelvic plexus nerves known as the cavernous nerves, extend directly into the erectile tissue of the penis known as the corpora cavernosa. It is important to note that the nerve innervating the penis sensory input (touch) is from the pudendal nerve.

Once inside the erectile tissue of the penis the nerves release different chemical compounds including nitric oxide, acetylcholine, and vasoactive intestinal peptide. These messengers then stimulate production of two other important communication molecules known as cGMP and see cAMP (stay tuned for why these are important later!).

These first and second signaling molecules allow for the muscle tissue inside the blood vessels of the penis to relax and thus allow blood flow in. Simultaneously there is a connective tissue, known as the tunica albuginea, that is rigid and traps blood by restricting venous outflow within the erectile tissue, thus building pressure, and creating an erection. In addition to vascular and nervous system signals, the voluntary muscle system becomes involved in male erection when the ischiocavernosus muscle of the pelvic floor helps to direct the erect penis to a more upright position.

For men, at the time of orgasm, there are multiple muscles that coordinate their actions that are under the control of the autonomic nervous system. These muscles are mostly non-voluntary muscle types and are located in the testicles, prostate, and pelvic floor muscles. It is worthy of mention, the prostate is innervated by the hypogastric nerve, responsible for sensory (pleasure-seeking input) whereas the penis is supplied by the pudendal nerve.

“Men can have deeper, more intense orgasms if they allow stimulation of the hypogastric nerve simultaneous with penile stimulation”.

Once orgasm is inevitable, rhythmic contractions begin stimulation of ejaculation and pressure builds. At the moment of orgasm, pelvic floor muscles intensify contractions in a rhythmic and involuntary pattern and the flow of ejaculation feels pleasurable as semen flows through the urethra. This is orchestrated through carefully coordinated movements, including the opening, and closing of specific sphincters originating in the prostate (Komisaruk et al., 2006).

It is important to note that while ejaculation and orgasm most frequently accompany each other it is not absolutely necessary to ejaculate to have an orgasm for a male human. Interestingly it has been reported that some men can achieve orgasm simply through meditation without physical touch.

After orgasm a man’s erection quickly relaxes, this is called detumescence (say that 5x fast!). This is due to the resolution of neurotransmitters being released in the brain, breakdown of communication molecules like vasoactive peptide, nitric oxide, and acetylcholine and their accompanying second messengers cGMP and cAMP, or sympathetic nerve stimulation creating a fight or flight response (e.g. the dog jumps on the bed unexpectedly, kids knock on the door, etc).

Next, we will dive into the complexities of the female orgasm. The Female Orgasm, Part 2 of the Science of Orgasms.


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Writer: Michelle Leary
Writer: Michelle Leary
November 30, 2022

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