Question

Are white blood cells specialized cells?

Answer 1

White blood cells are definitely specialised to provide us immunity: moreover the cells are motile, able to develop pseudopodia.

Explanation:

There are different types of white blood cells(WBC)/leucocytes. The distinction is done first, on the basis of granules: there are granulocytes and cells without are agranulocytes.

Now the names: remember that first three are granulocytes and last two are agranulocytes: I use a mnemonic to remember the order--

N ever E at B anana L ike M onkey

• N for Neutrophil
• E for Eosinophil
• B for Basophil
• L for Lymphocyte
• M for Monocyte

Each type of WBC is specialised for a particular fuction. The functions in brief are as follows:

Neutrophils attack invading germs and kill them by phagocytosis. Neutrophils are highly motile and are first immune cells to reach an area of infection.

Eosinophils help in fighting viral infections and parasitic helminths. They remove cell debris, and play predominant role in triggering allergic reaction.

Basophils secrete three important chemicals: heparin, histamine and serotonin. Heparin is natural anticoagulant. Histamine is vasodilator (dilates blood vessels) while serotonin acts in the opposite manner (constricts blood vessels). A tissue equivalent is mast cell with same functions.

Lymphocytes are unique, as these are main cells of immune system: distinguished in B cells and T cells. B cells, once matured, secrete specific protein molecules called antibodies which fight specific germs. Clones of B cells in tissue are called plasma cell . T cells are further differentiated in T helper, T killer and T suppressor. Antibody secretion by B cells starts after receiving trigger from T helpers. T killer cells provide cell mediated immunity.

Monocyte is phagocytic like neutrophils but they are superior for displaying the consumed foreign antigens. Circulating lymphocytes get an exposure to these alien molecules and become programmed to produce specific antibodies. Their equivalent in tissues are called macrophages : their phagocytic activity also helps in removing cell debris.

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