Throughout human history, our bodies have adapted to the outside environment in various ways, and our immune system is a frank representation of that adaptation. Our blood is a tissue, just like any other, and the cells that make up the blood are not adherent to each other but “swim” in a continuous motion in the fluid connective tissue known as plasma. Those cells are red blood cells, white blood cells and platelets. White blood cells are the only ones that have nuclei and they can be differentiated according to the shape of their nuclei and their color under the microscope. White blood cells are derived from common mother cells called the hemopoietic stem cells that are located mainly in the bone marrow.
Leukopenia is a medical term that means a fall in the number of white blood cells below normal. It may be isolated, which means that only white blood cells are affected, or may be a part of a pancytopenia which is the deficiency of all three blood elements.
Normal count of white blood cells
Neutrophils, basophils and eosinophils are grouped under the term granulocytes because of the appearance of different granules in their cells under the microscope.
The normal number of white blood cells is as follows:
♦ Total number = 4000-11000 per cubic milliliter
♦ Neutrophils = 2500-7500 per cubic milliliter
♦ Lymphocytes = 1500-3500 per cubic milliliter
♦ Monocytes = 200-800 per cubic milliliter
♦ Eosinophils = 40-400 per cubic milliliter
♦ Basophils = 10-100 per cubic milliliter
Leukopenia is when the total number if white blood cells falls below 4000 per cubic milliliter.