Misconceptions About Erections, Orgasms and Ejaculation!

WARNING:- This post is technical with medical anatomical discussions, but bear with me. Enhanced knowledge will lead to understanding when things don't go quite right (ED).

In my previous Penis Project post, I wrote about the 'Penis Conspiracy' and how what goes on in our brain influences our sex life. This post focuses on the physical side with the brain translating sensory input into arousal initiation, triggering the erection process and central in the genital sensory feedback to flood the body with feel-good hormones and orgasm.

The Three Stage Process of Erection

Normal erections generally depend upon 3 processes (ref.): 

1. increased arterial blood flow into the penis by neurological initiation, 
2. cavernosal smooth muscle relaxation, 
3. restriction of venous blood outflow from the penis.

I've included links to various medical websites for more complete descriptions, I focus mostly on the lesser understood aspects.

 (Click for the WebMD article)

From around 2005, understanding of the biochemical processes improved and the inter-relationship of psychological and physiological aspects were better understood. Working backward, the actual erection is caused by inflow of blood into the two 'corpus cavernosa'. This process is triggered by Nitric Oxide (NO), a signalling chemical sent from the nerve endings en-wrapping the cavernosum. (NO is synthesized from L-arginine by NO synthase (NOS)). The NO causes the blood vessel walls to relax encouraging blood inflow.  PDe5 inhibitor drugs like Sildenafil (Viagra) work by increasing bio-availability of Nitric Oxide. It is the signalling from the brain, initiated by a range of all sorts of erotic stimuli, touch, sight, smell, sound, that trigger this process. Conversely, inhibitory brain processes like depression, can suppress this triggering process.

Nitric Oxide is an important  component in general circulatory health. Certain foods and supplements boost Nitric Oxide levels. Whilst these might not be sufficient for treatment of persistent Erectile Dysfunction (ED), a good exercise regime, healthy eating including the above NO boosters, healthy weight level, controlled blood pressure, minimized alcohol consumption and healthy mind-set, will minimize the chances of developing ED.

Having achieved an erection, a separate process retains the erection. The Corpus Spongiosum runs down the under-side of the penis and is responsible for holding the urethra open and restricting the outflow veins so blood is retained, holding the erection. A different Nitric Oxide process (eNO) is involved in retaining an erection. This is also a signalling chemical from nerve endings, but these are triggered by physiological conditions of the erection, specifically 'hematological shear', which is a function of the actual blood flow affected by the flexibility and smoothness of the blood vessel walls and the viscosity of the blood. So a good psychologically aroused state can initiate a good erection, but aging or damaged blood vessels can limit retention. 

Overuse of alcohol affects blood viscosity which can lead to loss of erection, "Brewers Droop", known in Australia as "Fosters Droop". And remember that alcohol shouldn't be taken along with most medications. A little might be fine to relax to start an evening, but too much could deflate not just your ego. And alcohol generally doesn't go well with Viagra leaving you with a pounding headache afterwards.

WARNING:-  Viagra was originally developed for treatment of high blood pressure. It works in erection improvement by lowering blood pressure through release of Nitric Oxide. There are medical conditions that contraindicate its use - get a doctor's check before starting its use. Use the smallest dose needed - there is a maximum recommended dose - over-dosing can cause serious problems.

The Corpus Cavernosum Vessels

Note that the Corpus Cavernosum are in fact two blood vessels of sponge-like tissue, the length of the penis, that fill with blood to effect an erection. These vessels form in the fetus in the very earliest stages during development of the circulatory system. At the time of gender bifurcation, these vessels form either the penis or the female clitoral structure. It is an important lesson in sexuality for men to understand, that the female clitoral structure extends from the external head (analogous the the male glans) and extends internally with two Corpus Cavernosa, behind the labia, around the urethra and join the top wall of the vagina at the 'G spot'. So the female clitoris undergoes a penis like 'erection', swelling and puffing out the labia.

Understanding Orgasms and Ejaculation

The whole sexual arousal cycle is a feedback loop between sensory arousal in the brain flooding the body with hormones, and sensations in the genitals feeding signals back into the brain. In one sense, orgasm is arousal reaching a peak with a final 'explosive' flood of senses then 'collapses' into the 'resolution' phase. In females, orgasm triggers rhythmic contractions of muscles. Clitoral orgasms use muscles around the urethra and vaginal openings, the same muscles used in a male orgasm. A vaginal orgasm is contraction of the kegal muscles across the base of the pelvis and contract along the inner length of the vagina. In men, orgasm and ejaculation are in fact separate events.

Ejaculation is controlled by the sympathetic nervous system in the spinal cord.

In men, arousal causes a build up of ejaculate fluid within the 'bulb of the penis' located at the base. An observant woman might see the urethra on the underside of the penis, swelling and throbbing. This filling up leads to a special feeling of impending, uncontrollable ejaculation, although with practice, 'edging' allows you to pull back from the 'edge', then build up to almost the point of no return again, then pull back again.

With age, erection can in fact inhibit orgasm and ejaculation, with effectively numbing sensations. As the erection starts to deflate, ejaculation might then occur - warning: this condition can lead to condom slippage.

While men experience pelvic contractions, not unlike the female, they are not central to the male orgasm and ejaculation. Pelvic contractions can best be felt during prostate massage. Rhythmic ejaculation contractions primarily are caused by muscles at the base of the penis, rather than pelvic floor, although they are connected.

Origin and Composition of Ejaculate

Probably the biggest misconception, is the origin of ejaculate. Sperm is generated in the testicles and passes up the Vas (a Vasectomy cuts this Vas as a permanent contraceptive measure). The sperm mixes with fluid from the Seminal Vesicle and from the Prostate - by volume the majority is prostatic fluid. The outlet from the prostate joins the urethra through a valve and another valve above the junction stops urine mixing during ejaculation, and conversely ejaculate going back into the bladder (retrograde ejaculation). 

This misconception is perpetuated by porn talk about "draining balls". If anything, it is the prostate that is being 'drained'. 

Ejaculate from a man who has had a vasectomy contains no sperm and won't have a milky colour (so technically, no 'cream-pies'). If a man has had prostatectomy surgery (cutting out the prostate) for Prostate Cancer, there will be virtually no ejaculate and very poor, if any, orgasms (erection and coitus is still possible with an implant or injection, but sorry, no 'happy ending').