In the shaft of the penis there are two side-by-side chambers of spongy tissue called the corpora cavernosa. They're mainly responsible for erections. Just below them is another chamber called the corpus spongiosum. The urethra, which carries semen and urine, runs through the center of it.
The corpora cavernosa are made of small arteries and veins, smooth muscle fiber, and empty spaces. The chambers are wrapped in a sheath of thin tissue.
When you get an erection, signals from the brain or nerve endings in the penis cause the smooth muscle of the chambers to relax and arteries to dilate, or open wider. This allows a rush of blood to fill the empty spaces.
The pressure of blood flow causes the sheath of tissue around the chambers to press on veins that normally drain blood out of the penis. That traps blood in the penis. As more blood flows in, the penis expands and stiffens, and you have an erection.
When the excitement ends, the smooth muscle contracts again, taking pressure off the veins and allowing blood to flow back out of the penis. Then the penis returns to a flaccid state.
High Blood Pressure and Other Causes of Erectile Dysfunction
High blood pressure is a major cause of erection problems. A study in the Journal of the American Geriatrics Society found that about 49% of men ages 40 to 79 with high blood pressure had erectile dysfunction.
Another study of men with high blood pressure, published in the Journal of Urology, found that 68% of them had some degree of erectile dysfunction. For 45% of the men, it was considered severe.
High blood pressure keeps the arteries that carry blood into the penis from dilating the way they're supposed to. It also makes the smooth muscle in the penis lose its ability to relax. As a result, not enough blood flows into the penis to make it erect.
Men with high blood pressure may also have a low testosterone level. Testosterone is the male hormone that plays a big role in sexual arousal.
High blood pressure by itself can lead to erectile dysfunction. But some drugs for treating high blood pressure can actually be the cause as well.
Diuretics -- or water pills -- and beta-blockers are the high blood pressure drugs most commonly linked to erectile dysfunction.
Diuretics may cause erectile dysfunction by decreasing the force of blood flow into the penis. They may also decrease the amount of zinc in the body. Your body needs zinc to make testosterone.
Beta-blockers dampen the response to nerve impulses that lead to an erection. They also make it more difficult for the arteries in the penis to widen and let in blood. What's more, they can make you feel sedated and depressed -- and the mind always plays some part in sexual arousal.
Sometimes, the choices that some men with high blood pressure make can add to the problem. Smoking, especially, is one of those. Smoking increases blood pressure, and damages blood vessels and reduces blood flow all around the body.
The power to take control of your blood pressure and sexual health is in your hands. By living a healthy lifestyle and working with your doctor, there's a chance you'll once again be able to have normal sexual function.
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Burchardt, M. Journal of Urology, October 2000; vol 164: pp 1188-1191.
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