Question

Blood consists of two parts, a liquid part and a cellular part. Name these parts and briefly write about them.

Answer 1

• Blood is a special connective tissue consists of plasma (liquid part) and formed elements (cellular part). About 55% of blood comprises by plasma and nearly 45% by formed elements.
• Plasma is a straw coloured viscous fluid. 90-92% of plasma is water and proteins contribute 6-8% of it. Fibrinogens, globulins and albumins are the major proteins present in the plasma. Plasma also contains the small amount of minerals and clotting factors in the inactive form.
• Erythrocytes, leukocytes and platelets are collectively called formed elements.

1. Erythrocytes are most abundant and formed in red bone marrow in the adults. They are devoid of nucleus so as to maintain their biconcave shape. They have an iron-containing complex protein called haemoglobin and play an important role in the transport of respiratory gases.
2. Leukocytes are colourless due to lack of haemoglobin and are nucleated. They are involved in the defence mechanism of our body.
3. Platelets are the cell fragments produced from megakaryocytes. It is responsible for clotting of blood.