Question

Give a detail account on blood cells.

Answer 1

Blood contains corpuscles which are red blood cells (erythrocytes), white blood cells (leucocytes) and platelets. In this fluid connective tissue, the blood cells move in a fluid matrix called plasma.

• The plasma contains inorganic salts and organic substances. It is a main circulating fluid that helps in the transport of substances.

1.Red blood corpuscles (Erythrocytes):

• The red blood corpuscles are oval shaped, circular, biconcave disc-like and lack nucleus when mature (mammalian RBC). They contain a respiratory pigment called haemoglobin which is involved in the transport of oxygen to tissues.

2.White blood corpuscles (Leucocytes):

• They are larger in size, contain distinct nucleus and are colourless. They are capable of amoeboid movement and play an important role in body’s defense mechanism.

WBC’s are of two types:
i. Granulocytes (with granules in the cytoplasm):
Granulocytes have irregular shaped nuclei and cytoplasmic granules. They include the neutrophils, basophils and eosinophils.
ii. Agranulocytes (without granules in the cytoplasm):
Agranulocytes lack cytoplasmic granules and include the lymphocytes which have a spherical nucleus and the monocytes which have a large nucleus indented on one side.

• They engulf or destroy foreign bodies and neutralise their harmful effects.

3.Blood platelets:
They are minute, anucleated, fragile fragments of giant bone marrow called mega karyocytes.

• They play an important role in blood clotting mechanism.