The number of leukocytes, which represent typical nuclear cells, about 1000 times less than that of the erythrocyte. In 1 mm3 of blood contains only 6,000-8,000 leukocytes. Number of leukocytes less constant than the number of erythrocytes, and varies under normal physiological conditions. The number of white blood cells associated with fluctuations in solar activity, which results in an increase to reduce them.
Leukocytes are divided into granulocytes containing cytoplasm particular specific grain (neutrophils, eosinophils, basophils) and agranulocytes cytoplasm which does not contain grain, homogeneous (monocytes, lymphocytes).
The increase in the number of leukocytes in the blood is called leukocytosis. Leukocytosis observed under physiological conditions in the first 3-4 hours after eating (digestive leukocytosis) during muscular work, after shouting at children (myogenic leukocytosis), pregnant women (pregnant leukocytosis). The number of leukocytes in the blood is influenced by the central nervous system. There is also a static leukocytosis (horizontal leukocytes 2 times greater than the vertical).
The reallocation of leukocytes, due to changes in the lumen of blood vessels and blood flow in certain regions of the body, the absolute number of leucocytes in 1 mm3 varies greatly: neutrophil – 3300-5600, monocytes – 200-600, lymphocytes – 1200-2800, eosinophils – 100-250 , basophils – 20-80.
Reducing the number of leukocytes in the blood is called leukopenia. For example, a high dose of ionizing radiation in dogs WBC count decreases of 90%. The higher the dose, the more pronounced leukopenia. The most sensitive indicator of the severity of lesions in ionizing radiation – is dependent on the dose reduction in the number of lymphocytes – lymphopenia.
The physiological importance is not only the number of white blood cells, and the percentage of forms between them.
Increasing the number of lymphocytes in the human (over 40%) is designated as lymphocytosis. The increase in the number of eosinophils (6%) – eosinophilia. Increasing the number of monocytes (10%) – monocytosis.
White blood cells live from 2-4 to 12-15 days. Their main function – to protect the body from infectious germs and poisoning.