by A.R. Marth

Created on: April 09, 2007   Last Updated: May 02, 2007

"Out with his spleen!" On television medical dramas, the spleen seems like a disposable organ. Emergency care doctors are constantly removing them, dismissing them, and seem unconcerned with their function. Your spleen is important, though, even if losing it won't kill you.

Your spleen sits under your ribs on the left, and is about the size of your loosely clenched fist. It usually weighs in at about a half pound, but if you are ill with certain diseases, and right after you've eaten, it grows a bit.

To understand the spleen's purpose, you must know that in your blood there are millions of red blood cells. These carry oxygen to every cell in your body. While they are very useful during their short four months of life, the red blood cells eventually die, and are replaced with fresh, new, vigorous cells from your bone marrow. Your spleen is where antique red blood cells go to die.

Some of these are kept in reserve. You have about 6 quarts of blood in you, not counting the reserve your spleen contains. The spleen releases its reserve if you have a serious injury with heavy bleeding, and can buy more time for your other vital organs if this happens.

The most important function of a spleen is as a filter.Your spleen makes white blood cells, which are vital to the immune system. All the blood in your body eventually passes through your spleen, where these white blood cells attack anything foreign, like viruses and bacteria. This helps your body fight off infections and diseases.

While the spleen is not your only defense, it is definitely an important one. People who have no spleen may take longer to heal injuries, and are more prone to infections. While removing a spleen may be necessary if it's ruptured, since so much blood passes through it, this isn't an operation that can be taken lightly.

The appendix, now. That's another story.

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