phoenix 5 - to help men and their companions overcome issues created by prostate cancer
main menu   -   articles   -   prostate   -   stories   -   sexuality   -   resources   -   glossary   -   search
 
 

PHYSIOLOGY OF ERECTIONS:
HOW THEY OCCUR

Which is why various aids can help or not.


drawing of cross-section of penis (For a different description and line drawing, click here.)

The penis is composed of three different regions: a pair of parallel spongy columns called the corpa cavernosum and the central corpa spongiosum, which contains the urethra (the tube that carries urine from the body).

All three regions are made up of erectile tissue. Erectile tissue is rich in tiny pool-shaped blood vessels called cavernous sinuses, which are surrounded by smooth muscles and supported by elastic fibrous tissue.

The natural erection is prompted by the corpa cavernosa nerves (also known as cavernous nerves) which come to the penis from the prostate gland. Removal of the gland without sparing the nerves breaks the neural connection. The tissue cannot relax, allowing blood to flow in.
 
 
 
 
drawing showing veins open


In the flaccid, or unerect, normal penis, the small arteries leading to the cavernous sinuses contract, reducing the inflow of blood. The smooth muscles regulating the many tiny blood vessels within the penis also contract.

 
 
 
 
drawing showing arteries open
When a man becomes aroused, his central nervous system stimulates the release of a number of chemicals that relax the smooth muscles in the penis, allowing blood to flow into the tiny pool-like sinuses and flood the penis.

The spongy chambers almost double in diameter due to the increase in blood flow. The veins surrounding the corpa cavernosum and corpus spongiosum are squeezed almost completely shut by the pressure of the erectile tissue; they are unable to drain blood out of the penis, causing it to become rigid.

(For a different description and line drawing, click here.)

Go to
BASICS MENU
 
 

main menu   -   articles   -   prostate   -   stories   -   sexuality   -   resources   -   glossary   -   search

This information is provided for educational purposes only and does not replace or amend professional medical advice. Unless otherwise stated and credited, the content of Phoenix5 (P5) is by and the opinion of and copyright © 2000 Robert Vaughn Young. All Rights Reserved. P5 is at <http://www.phoenix5.org>. P5's policy regarding privacy and right to reprint are at <www.phoenix5.org/infopolicy>.