Erections & Erectile Disorders
Anatomy of a Penis
The penis is composed of three spongy erectile tissues. The corpus spongiosum surrounds the urethra (urine passage) and fills the glans (tip of the penis). The main erectile tissues, called the corpora cavernosa (or corporal bodies) are two, rod-shaped cylinders located in the shaft of the penis. These spongy tissues contain microscopic chambers called sinuses. Cavernosal arteries, deep within the centre of each of the corporal bodies carry blood to the penis.
Physiology of an Erection
The dynamics of how an erection is obtained are very complex. The following is a simplified explanation. Through the five senses of sight, touch, smell, hearing, and taste, the brain receives a message of arousal. Chemicals called neurotransmitters are then released, causing an increase of blood flow into the spongy erectile tissue and resulting in an erection. After orgasm and ejaculation, different neurotransmitters are released that constrict the corporal bodies and facilitate drainage of blood out of the penis. Hormones also play a role in erection. The male hormone, testosterone, is necessary for the normal growth and development of the male sex organs. It is also needed for arousal to occur.
