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Texas ISD School Guide
Texas ISD School Guide

Short Stories for Teachers

Blood Cells - The Basics
By:Elizabeth Blake

About half of your blood is liquid and the other half is made up of cells. The liquid is 90% water and is called "PLASMA."

There are three types of blood cells - RED BLOOD CELLS, WHITE BLOOD CELLS, and PLATELETS.


There are about 4 million RED BLOOD CELLS per microliter of your blood. Men have a little bit more than women usually do. These have hemoglobin in them, which binds to oxygen. These cells then carry the oxygen throughout your body in your bloodstream, reaching all your tissues.

RBC's are made up of iron. You need iron in your diet to make RED BLOOD CELLS.

Another term for RED BLOOD CELL is ERYTHROCYTE (cyte means cell.)


WBC's fight infection. Normally, you have between 5,000 and 10,000 WHITE BLOOD CELLS per microliter of your blood. WHITE BLOOD CELLS are categorized into two categories-granulocytes and non-granulocytes.

Granulocytes have granules in them that contain chemicals which attack and sometimes kill foreign substances. There are three types of granulocytes-neutrophils, eosinophils, and basophils.

Neutrophils are the most common granulocyte. They fight bacteria. The Neutrophil will surround a group of bacteria and engulf them, then dump the contents of its granules into the bacteria, killing the bacteria and the neutrophil both. Pus is made up of dead neutrophils and dead bacteria.

Eosinophils fight parasites and attack foreign substances. If your body sees bee pollen, for instance, as a foreign body, it will produce extra Eosinophils to fight the bee pollen. If your blood test shows a high percentage of Eosinophils, the doctor will know that there's a good probability that you have either a parasite, or an allergy.

Basophils help fight foreign substances also. Normally, there are zero to one percent Basophils in your blood. But if your body sees a foreign substance, it will produce extra Basophils which will dump the contents of their granules into the foreign substance in an attempt to kill it. The contents contain histamine. Histamine causes sneezing or itching. That's why you take an anti-histamine to counter-affect these symptoms.

The other category of WHITE BLOOD CELLS is non-granulocytes. There are two kinds of them--lymphocytes and monocytes. They usually fight viruses as opposed to bacteria.


PLATELETS are very small and sticky. If you're bleeding, they rush to the site, stick together, and form a platelet plug, sealing the capillary wall to help stop the bleeding.

The normal count is 150,000 to 450,000 per microliter in your blood.

Another name for PLATELET is thrombocyte.

All these blood cells are manufactured in your bone marrow. Lymphocytes are also produced in the lymph nodes.

After working 20 years as an ASCP certified Med Tech, I switched careers to teach science in an inner-city high school. I've written a memoir about the joys of teaching and the obstacles I fought. No Child Left Behind? The True Story of a Teacher's Quest by Elizabeth Blake on http://www.BarnesandNoble.com and Amazon. Drugs, gangs, a riot, shootings, murdered students, abusive principals - all contributed to the stress which eventually drove me from the students I loved. The book celebrates triumph over adversity. To read the first page, visit http://www.elizabethblakeonline.com

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