Question

Why are leucocytes classified as granulocytes and agranulocytes? Name each cell and mention its functions.

[Review question: Pg. No: 215]

Answer 1

The white blood corpuscles can be grouped into two categories: 1. Granulocytes.
2. Agranulocytes.
Granulocytes:
They contain granules in their cytoplasm. Their nucleus is irregular or lobed. The granulocytes are of three types
(i) Neutrophils
(ii) Eosinophils
(iii) Basophils

(i) Neutrophils:
They are large in size and have a 2 - 7 lobed nucleus. These corpuscles form 60% - 65% of the total leucocytes. Their numbers are increased during infection and inflammation.
(ii) Eosinophils:
It has a bilobed nucleus and constitute 2% - 3% of the total leucocytes. Their number increases during conditions of allergy and parasitic infections. It brings about detoxification of toxins.
(iii) Basophils:
Basophils have lobed nucleus. They form 0.5-1.0% of the total leucocytes. They release chemicals during the process of inflammation.
Agranulocytes:
Granules are not found in the cytoplasm of these cells. The agranulocytes are of two types:
(i) Lymphocytes
(ii) Monocytes

(i) Lymphocytes:
These are about 20-25% of the total leucocytes. They produce antibodies during bacterial and viral infections.
(ii) Monocytes:
They are the largest of the leucocytes and are amoeboid in shape. These cells form 5 - 6 % of the total leucocytes.They are phagocytic and can engulf bacteria.