An erection requires a substantial increase in penile blood flow. If the cavernosal arteries (the arteries to the corpora cavernosa) are unable to increase the blood flow to the penis, vascular E.D. will occur.
If a person has generalized atherosclerosis (fatty deposits narrowing the caliber of their arteries) as evidenced by angina, heart attacks, strokes, and/or claudication (leg and buttock pain that occurs with exercise and is indicative of poor blood flow), there is a great likelihood of penile arterial involvement as well. Diabetes, for example, is well known to give rise to atherosclerosis. Radiation therapy to the pelvis can cause scarring and damage to the penile circulation, thus resulting in vascular E.D. Because cigarettes contain nicotine (which functions to constrict blood vessels), E.D. commonly occurs on the basis of chronic cigarette use.
In many men, the arterial supply to the penis is intact, but because of venous leakage (a condition in which the otherwise rigid corpora cavernosa soften prematurely due to loss of blood through the veins), an erection cannot be sustained for long. The blood flow simply drains away from the corpora, resulting in flaccidity of the penis and the inability to maintain an erection. This is the underlying cause in about 70% of patients who suffer from ED. It is due to the loss of corporal smooth muscle such that sufficient relaxation to achieve obstruction of venous outflow cannot occur. The blood in the sinusoids leaks back into the venous system draining the penis. It is similar to essential hypertension, which is due to the loss of smooth muscle within the arterial walls that leads to stiff vessels in which relaxation is impaired.
Normal erectile function requires an intact brain, spinal cord, and peripheral nerve supply to the corpora cavernosa. Any interruption of the nervous system may result in E.D. since it is the nerve impulse to the cavernosal arteries that is the trigger for increased penile blood flow. Generic Viagra Mexico
Diabetes, besides causing damage to penile circulation, causes a penile neuropathy (nerve damage) that commonly results in E.D. Alcohol abuse similarly may give rise to a neuropathy accounting for E.D. In fact, any neurological disease process (including multiple sclerosis, Parkinson’s disease, spina bifida, etc.) may result in E.D. Injury or trauma to the brain, spinal cord, or pelvis may cause E.D. on a neurogenic basis. A pelvic fracture may injure the nerve supply to the corpora cavernosa. Radiation therapy, besides causing damage to penile circulation, can damage the cavernosal nerve supply. Radical pelvic surgery (most commonly for bladder, prostate, or rectal cancers) may require removal of the cavernosal nerve supply, resulting in E.D.