The steps leading to an Erection

• Sexual stimulation and arousal
   
• Impulses from the brain and penile nerves
   
• Relaxation of smooth muscles in the two spongy spaces (corpora cavernosa) in the penis
   
• As the spaces rapidly fill with blood, the flaccid penis inflates to become stiff and elongated.
   
• Increase in blood flow to the penis
   
• The tunica albuginea membrane surrounding the spongy spaces trap this blood
   
• Flaccid penis inflates to elongate and become rigid
   
• Erection achieved
   

When the contraction of these smooth muscles leads to an outflow of blood, the erection is lost and the penis returns to its flaccid state.
 

Erectile Dysfunction

Erectile dysfunction (ED) is defined as the repeated incapability to get or keep an erection firm enough for sexual intercourse. It is true that ED affects between 15 and 30 million men all over America, depending on the various degrees of dysfunction. ED can either mean a total or even partial inability to achieve or maintain an erection. This gives the definition a very wide array of meaning, and makes it difficult to make estimates in terms of cases.
 

Causes of Erectile Dysfunction

It is to be noted that Erectile Dysfunction can occur if any of the events in the sequence leading to an erection are interrupted. The reasons may be in some mental processes, nerve impulses in the brain, spine and genital area, or responses in smooth muscles, fibrous tissue, veins and arteries in and around the corpora cavernosa of the penis.
 

The most common causes of ED are damage to nerves, arteries, smooth muscles, and fibrous tissues, often resulting from diseases such as diabetes, kidney disease, chronic alcoholism, multiple sclerosis, atherosclerosis, vascular disease, and neurologic disease. These account for about 80% of ED cases. Between 35 and 50% of men with diabetes experience ED.
 

Surgery, usually Radical Prostate and Bladder Surgery for Cancer can injure nerves and arteries near the penis, causing ED. Injury to the penis, spinal cord, prostate, bladder, and pelvis can lead to ED by damaging nerves, smooth muscles, arteries, and fibrous tissues of the corpora cavernosa of the penis.

Moreover, certain kinds of sedentary lifestyles, which usually contribute to heart disease and vascular problems, also raise the risk of erectile dysfunction. Smoking, obesity, and lack of exercise have been reported as possible causes of ED. Smoking affects blood flow in the veins and arteries and may cause hormonal abnormalities such as variation in testosterone levels.
 
  In addition, many commonly used medicines like blood pressure drugs, antihistamines, antidepressants, sedatives and even appetite suppressants can produce ED as a side effect.
 

It is believed that psychological factors such as stress, anxiety, guilt, depression, low self-esteem, and fear of sexual failure cause about 20% of ED cases. Men with a physical cause for ED frequently experience psychological reactions to some extent as well, making psychological factors the secondary cause for the problem.
 

Erectile Dysfunction Diagnosis

The first step conducted by a physician is a comprehensive examination to determine when and how the condition might have developed, other physical and psychological conditions and medications taken, if any. If an evident physical cause is suspected, blood tests are first taken to check hormonal levels and to eliminate probable diseases from the list discussed above.
 

Additional specialized clinical tests may also be done:

Penile nerve function:
Physical tests are performed to determine sufficient nerve sensation in the penis. In patients who have damaged nerves, other tests are performed to determine the normalcy of touch sensation in the genital area.

Nocturnal penile tumescence (NPT):
In general, men have five to six erections during the night, in their sleep, the absence of which may point to some problem with nerve function or arterial circulation in the genital area. Various methods are used to measure changes in rigidity and girth of the penis during nocturnal erections.

Ultrasonography:
Duplex ultrasound is used to evaluate the adequacy of arterial circulation in the penis, i.e. blood flow, scarring of erectile tissue, signs of atherosclerosis and venous leak. The test is taken before and after injecting an external medication to check if the blood flow to the penis gets any better.

Cavernosometry:
Cavernosometry determines the vascular pressure in the penis. A dye is injected into the veins and arteries of the genital area to monitor any possible peculiarity in the arterial circulation in the penis.