Question

What are WBC, RBC and Platelets?

Answer 1

Hint: Blood is a connective tissue consisting of fluid matrix, plasma and formed elements. It is the most common medium of nutrient transport fluid in animals. Lymph is another liquid medium that helps in transport of certain substances.

Complete answer:
The formed elements comprises erythrocytes, leukocytes and platelets. Erythrocytes are known as the Red Blood Cells or RBCs. They are the most abundant cells formed in the bone marrow in adults. Nucleus is absent in RBCs. They are biconcave in shape and have red coloured iron containing a complex known as haemoglobin. The life span of RBCs is 120 days and they are destroyed in the spleen.
Leukocytes are also known as White Blood Cells or WBCs. They are colourless due to lack of haemoglobin. They are short-lived and are nucleated. WBCs are of two types-
Granulocytes- They comprise Neutrophils, eosinophils and basophils.
Neutrophils are monocytes and phagocytic cells which destroy foreign organisms entering the body. Basophils secrete amino acids and hormones such as histamine, serotonin, etc. They are involved in inflammatory reactions. Eosinophils are associated with allergic reactions and resist infections.
Agranulocytes- Agranulocytes include lymphocytes and platelets. Lymphocytes are of two types, B cells and T cells. They make the immune system of the organism’s body. Another name of platelets is thrombocytes. They release substances responsible for coagulation and clotting of blood.

Note:
Plasma is a straw coloured, viscous fluid which is mostly made of water and proteins. Maor proteins are fibrinogen, globulins and albumins. Fibrinogen aids in clotting of blood. Globulins help in the defence mechanism and albumin aids in maintaining osmotic pressure of the body.