The Male Anatomy

For many people, talking about the penis is tough. This area of the body is considered private and is usually not discussed publicly. However, the penis is simply a part of the male anatomy designed to accomplish a task, and we'll treat it that way here.

In the case of the penis, there are actually two tasks that it handles:

1. releasing urine from the bladder, known as urination
2. releasing sperm and seminal fluid from the prostate gland, known as ejaculation

Viagra® helps with the second task: ejaculation.

When things are working properly, ejaculation is a three-step process:

1. The man becomes sexually aroused.
2. The penis responds by becoming erect.
3. Stimulation of the penis causes ejaculation.

That sounds simple enough, but in many cases, step two does not happen, making step three difficult or impossible. Although the man is stimulated, the penis does not become erect. To understand why, you need to understand the technology of an erection.

When you want to move nearly any part of your body, you do it using muscles. Whether you are moving your fingers, toes, arms or legs, muscles do the work. Even when you stick your tongue out, you do it using muscles:

• You think about moving some part of your body
• The appropriate muscles contract
• That part of the body moves

Muscles let you move your body voluntarily with precise control.

The penis, on the other hand, is completely different. There are no muscle contractions involved in making the penis erect. To become erect, the penis instead uses pressure.

Probably the easiest way to understand how the penis becomes erect is to think about a balloon. If a balloon has no air in it, it is limp. As you inflate a limp balloon with just a little air, it becomes elongated and rigid.

The penis uses a similar mechanism, but instead of using pressurized air to become rigid, the penis uses pressurized blood. The penis contains two cigar-shaped structures, called corpora cavernosa (singular - corpus cavernosum), that it uses to become erect.

Think of the corpora cavernosa as balloon-like tubes. Arteries bring blood into these two tubes, and veins carry blood away from them. The penis can be either limp or erect, depending on the flow of blood:

• In a non-erect state, the arteries that bring blood into the corpora cavernosa are somewhat constricted, while the veins that drain the blood from the penis are open. There is no way for pressure to build inside the penis. In this state, the penis is limp.

• When a man becomes aroused, the arteries leading into the penis open up so that pressurized blood can enter the penis quickly. The veins leaving the penis constrict. Pressurized blood is trapped in the corpora cavernosa, and this blood causes the penis to elongate and stiffen. The penis is erect.

If the arteries leading to the penis do not open up properly, it is difficult or impossible for a man to become erect. This problem is the leading cause of erectile dysfunction (ED).

To solve an erection problem when the cause is poor blood flow, you need to open the arteries. Let's take a look at how this can be done -- and how it was done before Viagra.