Unlike women, most of the male reproductive system is located outside of the body. The external parts are the scrotum, the testicles and the penis.
The penis may be best known as the male organ for sexual intercourse as it contains numerous nerve endings.
HowStuffWorks.com says the penis has two jobs. One is to release urine from the bladder. The second is to release sperm and seminal fluid from the prostate gland, known as ejaculation.
The penis is composed of three sections. The first is the root. According to CBS News, the penis is shaped like a boomerang. That’s because the root is actually tucked up inside the pelvis and attached to the pubic bone.
The next section is the body or shaft. PenileSecrets.com says inside there are three internal chambers. Two large chambers on the top are known as the corpora cavernosa and one smaller chamber on the bottom is called the corpus spongiosum. The corpus spongiosum is used mainly for urination and ejaculation.
Special, sponge-like erectile tissue makes up these cigar-shaped chambers. HowStuffWorks.com says when a man becomes aroused, the arteries leading into the penis open up so pressurized blood can enter 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 Cleveland Clinic adds the skin of the penis is loose and elastic to accommodate changes during an erection. And when the penis is erect, the flow of urine is blocked from the urethra, allowing only semen to be ejaculated at orgasm.
The third part of the penis is the glans or the head. KidsHealth.org says at the end of the glans is a small slit or opening, which is where semen and urine exit the body through the urethra. It is also covered with a loose layer of skin known as foreskin. This is sometimes removed in a procedure called circumcision.
CBS News reports the male penis does have a mind of its own. It's true that men have less command over their penis than other body parts. That's because the penis answers to a part of the nervous system that's not always under conscious control. This is called the autonomic nervous system, which also regulates heart rate and blood pressure.
Men’s Health reports there are two types of penises. “Growers” expand and lengthen when becoming erect. “Showers” appear big most of the time, but doesn't get much bigger after achieving erection.
Sources:
The Male Reproductive System
http://www.cchs.net/health/health-info/docs/2300/2376.asp
A Body Basics Article: the Male Reproductive System
http://kidshealth.org/parent/general/body_basics/male_reproductive.html#
The Male Reproductive System
http://health.howstuffworks.com/sexual-health/male-reproductive-system/male-reproductive-system.htm
Things You Didn't Know About Your Penis
http://www.cbsnews.com/stories/2008/03/19/health/webmd/main3949777.shtml
15 Facts You Didn't Know About Your Penis
http://www.menshealth.com/mhlists/penis_facts
So How Does It Work?
http://www.penilesecrets.com/howitworks.html
How Viagra Works
http://science.howstuffworks.com/viagra1.htm
Reviewed August 10, 2011
by Michele Blacksberg R.N.
Edited by Jody Smith