Question

What is blood? Mention various blood corpuscles present in human blood. Write a note on the functions of blood.

Answer 1

Blood refers to a body fluid present in the human beings and various other animals. It helps in transporting essential substances within the body. It transports oxygen and necessary nutrients to the cells while carrying metabolic wastes away from them.

Complete answer:
In human blood, following blood corpuscles are found suspended into the plasma of blood:
Red Blood Corpuscles (also known as Erythrocytes)
These are found in abundance in the blood.
These are flat and round biconcave discs having a thin center which is sunken while the rim is thick.

Red blood cells are enucleate, meaning they do not possess cell nuclei.
-They consist of hemoglobin.
-Iron is present in hemoglobin which is responsible for providing red color to RBCs.
-They do not possess self-repairing capability.
-Life time of red blood cells is 120 days.

White Blood Corpuscles (also known as Leukocytes)
-They form an important part of the immune system.
-They are fewer in number as compared to red blood cells.
-They are present in the bloodstream, lymph system and the connective tissues.
-They are formed in the bone marrow from hematopoietic stem cells.
-They may be granulocytes (cells having granules) or agranulocytes (cells without granules).
-WBCs include various types of cells, namely, Eosinophils, Neutrophils, Lymphocytes, Basophils and Monocytes.

Platelets (also known as Thrombocytes)
-They do not carry out reproduction.
-They are enucleate, which means they lack nucleus in their cells.
-They help in blood clotting mechanisms.

Note: Blood helps in carrying nutrients and oxygen to various tissues of the body. At the time of injury, platelets form clots as a function to prevent excess loss of blood from the body. Also, blood carries cells and antibodies which help the body to fight against various infections. Moreover they help in regulating temperature of the body and transporting metabolic waste to the liver and kidney thereby filtering the blood.