Red blood corpuscles are also known as Erythrocytes. It shows the following properties:
(i) Production:
(a) The formation of RBC is called erythropoiesis. It requires hormone erythropoietin secreted by the kidney.
(b) In adults, it takes place in the red bone marrow.
(c) In fetus, it takes place in the spleen and liver.
(ii) Life span: 100 – 120 days.
(iii) Destroy: It destroys in spleen and liver. Spleen is called the graveyard of RBC.
(iv) Quantity (Total RBC count):
(a) Normal value in males: 5.1 – 5.8 million/mm3 of blood.
(b) Normal value in females: 4.3 – 5.2 million /mm3 of blood.
(v) Structure:
(a) Shape: Circular biconcave cells. Its edges are thicker than centre.
(b) Size: Diameter - 7 µm, Thickness – 2.5 µm
(c) Nucleus: Nucleus is absent, hence they are called enucleated cells. All mammalian RBCs are enucleated except those of Camels and Llamas.
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.
Eosinophils are granulocytes which comprise 3 % of the total WBCs. They contain coarse granules that stain with acidic dyes like eosin. They are 10-12 µ in size. The nucleus is bilobed. Eosinophils are non- phagocytic cells. They detoxify the blood by removing antigen-antibody complexes. The number of eosinophils increases during an allergy and this is termed as eosinophilia.