Erectile Dysfunction Treatment

How does erection and ejaculation occur?

Posted In Erectile Dysfunction Facts - By admin on Thursday, March 3rd, 2016 With No Comments »

How do  erection and ejaculation occur?

Touch, sights, sounds, erotic memories, fantasies etc, cause sexual excitement.

These stimuli increase signal output from a part of the brain called the paraventricular nucleus. These signals then pass through special autonomic nerves in the spinal cord, the pelvic nerves and the cavernous nerves that run through the prostate gland to reach the corpora cavernosa and the arteries that supply them with blood. In response to these signals, the muscle fibres in the corpora relax, allowing blood to fill the spaces between them.

Muscle fibres in the arteries that supply the penis also relax, and there is an eight-fold increase in blood flow to the penis. The increased blood flow expands the corpora, then stretches the surrounding sheath (the tunica).As the tunica stretches, it blocks off the veins that take blood away from the corpora cavernosa. This traps blood within the penis, the pressure becomes very high and the penis becomes erect.During an erection pressure in the penis is at least twice the pressure of blood in the main circulation. This is possible because the muscles of the pelvic floor contract around the base of the corpora cavernosa. At orgasm, the signalling from the brain changes dramatically. There is a sudden increase in noradrenaline production from nerves in the genitalia. This seems to both trigger orgasm and contract the muscle fibres in the corpora cavernosa and their supplying arteries.

Penis Anatomy

 

The pressure within the corpora drops, which also relaxes the tunica and so allows blood to flow out of the penis. Hormones, blood vessels, nerves, and muscles must all work together to make an erection. Your brain starts an erection by sending nerve signals to the penis when it senses sexual stimulation. Touching may cause this arousal. Another trigger may be something you see or hear. It may be a sexual thought or dream.

The penis contains two chambers called the corpora cavernosa, which run the length of the organ. A spongy tissue fills the chambers. The corpora cavernosa are surrounded by a membrane, called the tunica albuginea. The spongy tissue contains smooth muscles, fibrous tissues, spaces, veins, and arteries. The urethra, which is the channel for urine and ejaculate, runs along the underside of the corpora cavernosa. Erection begins with sensory or mental stimulation or both. Impulses from the brain and local nerves cause the muscles of the corpora cavernosa to relax, allowing blood to flow in and fill the spaces. The blood creates pressure in the corpora cavernosa, making the penis expand. The tunica albuginea helps trap the blood in the corpora cavernosa, thereby sustaining the erection. When muscles in the penis contract to stop the inflow of blood and open outflow channels, erection is reversed.

An erection occurs when blood is pumped into the penis and stays there, making it hard. It generally happens because  a  guy  is  thinking about sex,  or because his penis is being stimulated.The result is that signals go down the nerves that lead from his spinal cord to his genitals. They tell the blood vessels which supply the penis to open up. Blood flows in and the organ ‘blow up’ like a balloon. A valve mechanism near the base of the penis keeps the blood from flowing out again – a least until sex is over.As you can see, getting an erection is a complex process. It’s awfully easy for various factors to interfere with it – for instance, worry, tiredness, too much alcohol or in later life, narrowing of the blood vessels. Nicotine is now known to narrow those vital blood vessels – which is why ED is much commoner in smokers. But often, there is nothing physically wrong with men who develop ED.The pressure from the expanding penis compresses the veins (blood vessels that drain the blood out of the penis) in the tunica albuginea, helping to trap the blood in the corpora cavernosa, thereby sustaining an erection. Erection is reversed when cGMP levels in the corpora cavernosa fall, causing the smooth muscles of the corpora cavernosa to contract, stopping the inflow of blood and opening veins that drain blood away from the penis. The levels of the cGMP in the corpora cavernosa fall because it is destroyed by an enzyme called phosphodiesterase type 5 (PDE5)

About -