Q. Which of the following cells does not exhibit phagocytic activity?
Solution:
Basophils are types of granulocytes making only 0.5% of WBCs. They are 8-10µ in size. They contain coarse granules that stain with basic dyes like methylene blue. The nucleus is twisted with 2-3 lobes. These are non- phagocytic cells. They secrete an anticoagulant called heparin and secrete histamine which is involved with inflammation and allergic reactions.
Phagocytosis is the process of engulfing micro-organisms, directly by cells. Cells performing phagocytosis are called phagocytes.
There are three phagocytes:
(1) Neutrophils: Granulocyte (WBC).
(2) Monocyte: Agranulocyte (WBC).
(3) Macrophage: Cells of areolar connective tissue.
Macrophages are also wandering phagocytes.
Other examples of macrophages are Kupffer cells in the liver, Clara cells in the lungs.
Neutrophils are granulocytes which comprise 60-65 % of WBCs. They are 10-12 µ in size. Their cytoplasm contains fine granules that stain with neutral dyes. The nucleus is multilobed with 3-5 lobes and are hence called poly-morpho-nuclear leucocytes or polymorphs. They are early phagocytes that engulf micro-organisms protecting the body from infection and hence, are called phagocytes of acute infection.
Monocytes do not contain any granules in their cytoplasm and are thus called Agranulocytes. They make 5% of total WBCs. They are the largest WBCs with a size of 12-15 µ. The nucleus is large with a kidney shape. The monocytes can continue phagocytosis for a prolonged period and are hence called phagocytes of chronic infection. The monocytes liberated at the site of infection are also
converted into macrophages.
There are three phagocytes:
(1) Neutrophils: Granulocyte (WBC).
(2) Monocyte: Agranulocyte (WBC).
(3) Macrophage: Cells of areolar connective tissue.
Macrophages are also wandering phagocytes.
Other examples of macrophages are Kupffer cells in the liver, Clara cells in the lungs.
Neutrophils are granulocytes which comprise 60-65 % of WBCs. They are 10-12 µ in size. Their cytoplasm contains fine granules that stain with neutral dyes. The nucleus is multilobed with 3-5 lobes and are hence called poly-morpho-nuclear leucocytes or polymorphs. They are early phagocytes that engulf micro-organisms protecting the body from infection and hence, are called phagocytes of acute infection.
Monocytes do not contain any granules in their cytoplasm and are thus called Agranulocytes. They make 5% of total WBCs. They are the largest WBCs with a size of 12-15 µ. The nucleus is large with a kidney shape. The monocytes can continue phagocytosis for a prolonged period and are hence called phagocytes of chronic infection. The monocytes liberated at the site of infection are also
converted into macrophages.