Erectile dysfunction or “impotence” is the repeated inability to get or keep an erection that is sufficiently firm to achieve the kind of sex desired by a man and his partner.
Erectile dysfunction or ED can be the total inability to get an erection, an inconsistent ability to do so or a tendency to sustain only brief erections. These variations make defining ED and estimating its prevalence difficult.
It is thought to affect at least one in ten men in the UK. This means that there are an estimated 2.3 million men suffering with erectile dysfunction. In men over 40 years old, more than 50% will experience some form of ED, but despite its prevalence it is estimated that only 10% of men are being treated.
An erection is a complex event that requires the interaction of the brain, nerves, hormones and blood vessels.
The shaft of the penis consists of two erectile bodies called the corpus cavernosum, which comprises a mass of smooth muscle and endothelial-lined vessels and spaces (lacunae), richly supplied with nerve endings. The urethra, which is the channel for urine and ejaculate, runs along the underside of the corpora cavernosa and is surrounded by the corpus spongiosum.
As a result of psychological or physical sexual stimulation, the brain sends messages through the nervous system to the penis. These messages relax the smooth muscles in the blood vessel walls of the corpus cavernosum, causing them to open wider. When this happens, more blood flows through the vessels, filling the corpus cavernosum. At the same time, the veins that carry blood away from the penis shut down, causing an increase in blood pressure in the penis. The blood that is trapped within the corpus cavernosum causes the penis to become hard and erect.