In men the sexual inabilities often take the form of penile erectile dysfunction. Erectile dysfunction refers to the lack of penile firmness or lack of sustenance to perform the sexual intercourse. In order to understand how ED sets in, we have to understand what makes for the erection in the first place.

Let's explain it in simple way avoiding the medical jargons:

Following any sexual stimulation, the blood vessels in the penis expand to allow increased flow of blood in its two chambers. This makes the penis enlarge in both length and the firmness is enhanced. This is one aspect of the process of penile erection.

Now this enlargement due to the additional flow of blood does not complete the process. The blood has to remain there to sustain the firmness to support the act of intercourse. This sustenance also allows you to control the moment of ejaculation.

This whole process of erection is controlled by a mechanism which in medical term is called the veno-occlusive mechanism. This ensures that blood does not leak into the veins that drain blood away from the penis.

Now you might be wondering what makes for this rush of blood into the penis in the first place? This is the combined working of several factors.

The first factor relates to the nerves that are responsible of carrying two types of stimulatory messages---the first is psychic or mental and second is the sensory or relating to touch. These two types of messages can operate independently of the other.

So any sexual stimulus in forms of erotic thoughts or touches can send a neurological message to the blood channels within the penis. This makes the channels open up, bloods rush in and the penis gets enlarged in size.

The psychic stimuli on the other hand depend to a large extent on the male sex hormone, testosterone, which also plays an important role to enhance the initiation and maintenance of the erection.

Let's summarize the whole thing: The three factors working for the penile erection are

1. Blood supply to the penis

2. The efficiency of nerves to supply stimulus to the penis

3. Proper hormonal back up especially within the brain

4. Adequate psychic stimuli

There are chances of setting in of ED, if one or more of these factors go missing or are supplied in inadequate quantity.

Now let's briefly discuss how and when these essential components of erection fall out of line.

1. ED occurs when disrupted by an inefficient vascular system. Vascular health can be affected by such factors as high cholesterol leveling the blood, heavy smoking, diabetes or obesity. In older men ED may occur simply because of the narrowing of the blood vessels.

2. ED may occur as a result of inadequate nerve supply to the penis due to the trauma to nerves such as spinal cord injury, followed by an accident or diabetic nerve destruction and so on.

3. Reduced level of testosterone due to adverse testicular events like inflammation, drug side effects or vascular impairment may lead to low sex drive culminating into erectile dysfunction.

4. The stresses and tensions of modern living can impede the erectile process in a number of ways. They can completely dampen the sexual stimuli thereby preventing either the attaining or the sustaining erection.

This knowledge about causes of penile dysfunction will help you to choose the proper treatment of ED.