Transportation Of Blood The Cardiac Muscle Impluses Transportation In Blood Plasma Red Blood Cell
White Blood Cell Platelets Blood Vessles Arteries Capillaries Vein Distribution Of Blood
White Blood Cell
There are five common types of white blood cells, or leukocytes, which together make up less than 1% of the total cellular component of the blood. These cells are distinguished from one another by their staining characteristics, size, and the shape of their nucleic. All of these are derived from cells that originate in bone marrow. Most white blood cells function in some way to protect the body against foreign invaders and use the circulatory system to travel to the site of invasion. For example, monocytes and neutrophils travel through capillaries to wounds where bacteria have gained entry, then ooze out through narrow openings in the capillary walls. After leaving the capillaries, monocytes differentiate into macrophages, amoebalike cells that engulf foreign particles. Macrophages and neutrophils feed on bacterial invaders or other "foreign" cells including cancer cells. They often die in the process, and their dead bodies accumulate and contribute to the white substance called pus, seen at infection sites.
Lymphocytes, are white blood cells responsible for the production of antibodies that help provide immunity against disease. Cells that give rise to lymphocytes migrate from bone marrow to tissues of the lymphatic system such as the thymus, spleen, and lymph nodes. Least abundant are the eosinophils and basophils. Eosinophil production is stimulated by parasitic infections. Eosinophils converge on the parasitic invaders, releasing substances that kill the parasite. Basophils release substances that inhibit blood clotting as well as chemicals, such as histamine, that participate in allergic reactions and responses to tissue damage and microbial invasion.