Question

How do white blood cells fight pathogens?

Answer 1

The white blood cells are the component of blood and lymph that help to fight the infection which gets produced by the foreign pathogen. The white blood cell is of five different types and different leukocytes perform different functions.

Complete answer:
The white blood corpuscles are also known as leukocytes which are found in blood and lymph in the active form. It is colourless, nucleated, and irregular in shape. When a pathogen enters the body, the immune system present in our body starts to produce antibodies by multiplication through the lymphocyte, which help to invade the pathogen and destroy them. The leukocytes are divided into granulocytes and agranulocytes. The granulocytes consist of granules and irregular nucleus in the cytoplasm and it is divided into eosinophils, basophils, neutrophils. Eosinophils help to resist infections associated with allergic reactions and it also helps in dissolving the blood clot, basophils release histamine, serotonin, and heparin which involve in the inflammatory reactions and neutrophils engulf foreign germs and dead cells of the body. The agranulocytes are divided into lymphocytes and monocytes. The lymphocyte are non-phagocytic and it secretes antibodies which destroy microbes and its toxins, kill tumor cells and it also helps in healing whereas monocytes are phagocytic which engulf germs and cell debris and it gets to change into macrophages after entering the tissue spaces.

Note:
The rise in the number of WBC causes leukocytosis which leads to acute bacterial infections and in severe cases, it causes malignancies of blood known as leukemia or blood cancer. Fall in WBC count causes leukopenia which leads to higher chances of infection due to the weak immune system.