health

Erectile Dysfunction (ED) is a medical condition that affects more than
18 million American men. Men with ED are unable to achieve and
maintain an erection long enough to have sexual intercourse. In order
to understand what causes ED, it is important to know how the penis
becomes erect.

Anatomy of an Erection The shaft of the penis contains several
structures that work together to make the penis erect. The corpus cavernosum
are two long, sponge-like structures that run along the length of
the penis. They contain erectile tissue, two main arteries, several veins,
and nerves. Beneath the corpus cavernosa is the urethra, the tube that
carries semen and urine to the outside of the body through the meatus,
the opening in the head at the end of the shaft.
An erection occurs due to a combination of factors, both physical and
mental. When a man becomes sexually aroused, his brain sends chemical
signals such as epinephrine, norepinephrine, acetylcholine, prostaglandins,
and nitric oxide to the nerves inside the penis. When the nerves
receive these signals, the muscles in the penis relax and the spongy corpus
cavernosum fill with blood, causing the penis to become erect. As long
as a man continues to be aroused, the volume of blood flowing into the
penis remains high, maintaining his erection.

Understanding Erectile Dysfunction Sometimes, even when a man
is sexually aroused, he may have difficulty developing an erection. Other
times, a man may achieve an erection, but it does not last long enough to
allow him to engage in sexual intercourse. Usually this happens because of
a problem with the extra blood flow that the penis needs in order to maintain
an erection. Many factors can cause ED. Sometimes, ED is caused by
psychological factors such as depression, anxiety, and stress, and in other
cases, a serious underlying medical condition present.