Types and functions of white blood cells

Types of white blood cells

Five types of white blood cells.

1: Neutrophils

They comprise 60-70% of WBCs. They contain nuclei with 2-5 lobes. When body get infected, neutrophils are usually first of white blood cells to respond to the infection. They stay in the circulation for almost 10-12 hours and then pass to other tissues, where they become able to move and seek out and phagocytize the bacteria, antigen-antibody complexes, and other foreign matter. They also secrete lysozymes, which kill certain bacteria. After leaving circulation, they survive for 1-2 days.

2: Eosinophils

They are 2-4% of white blood cells. They contain two lobed nuclei. They are crucial in the protection against certain worm parasites. They do not phagocytize the large parasites; they get attached to worms and release the substances that destroy the parasites. By producing the enzymes, they modulate the inflammatory response. Enzymes will destroy the inflammatory chemicals for example histamine.

3: Basophils

They are 0.5-1% of WBCs. They release histamine inside the tissues to increase inflammation. They also release the blood clotting inhibitor called heparin.

4: Monocytes

They are 3-8% of white blood cells. They are largest of the WBCs. They normally stay in circulation for almost 3 days. After that they quit the circulation, become transformed into macrophages, and then they move to different tissues where they phagocytize cells fragments, bacteria, dead cells and other debris.

5: Lymphocytes

They are 20-25% of white blood cells. They are smallest of all white blood cells in size, but they are usually slightly larger in diameter than white blood cells. Although they originate in red bone marrow, they move through blood to lymphatic tissue where they can divide and produce more lymphocytes. They are located in lymphatic tissues such as lymph node, thymus, spleen, lymphatic nodules, and spleen.

There are two types of lymphocytes,

B cells: They produce antibodies against bacteria or toxin to kill them.

T cells: they protect against viruses and other intracellular organisms by killing or attacking the cells in which they found. They also destroy tumor cells and induce tissue graft rejection.