7. Blood

Question 1

What do you know about leukocytes? Explain the terms diapedesis, leukocytosis, leukopenia.

Answer 1

Leukocytes or white blood cells (WBCs) are crucial to defend the body against diseases. The account for less than 1% of total blood volume and they are the only complete cells in blood. that is to say they contain nuclei and the usual organelles.
WBCs defend the body against damage by bacteria viruses, parasites, and tumor cells. In addition, they have special features.
Unlike RBCs that are confined to the bloodstream, WBCs are able to slip into and out of the blood vessels. This process is called the diapedesis.
The circulatory system is just their means of transportation to areas of the body where their services are needed for inflammatory or immune responses.
When leukocytes mobilize for action the body speed up their production.
Leukocytosis happens when there are more than 11, 000 WBCs per cubic millimeter. It usually indicates that there is a bacterial or viral infection in the body. Otherwise leukopenia is an abnormally low WBC count. It is usually caused by certain drugs, such as corticosteroids and anticancer agents.
WBCs can be classified into two major groups: granulocytes and arganulocytes.