Body fluids are required for the continuous supply of nutrients and removal of wastes from the cells. Body fluids include blood, interstitial fluid and lymph.
Blood is a liquid connective tissue that consists of 55 per cent liquid plasma and 45 per cent formed elements called blood cells. Plasma is a straw-coloured fluid constituting of 90 to 92 per cent water, 6 to 8 per cent proteins, 1.2 per cent nutrients and gases and 0.8 per cent inorganic salts. The major proteins in plasma include albumins, globulins and fibrinogens. Plasma also contains organic nutrients such as glucose, amino acids and fats, respiratory gases and inactive clotting factors.
There are also traces of inorganic salts such as sodium, calcium, magnesium and bicarbonate in plasma. The remaining 45 per cent of blood is made of formed elements that include erythrocytes, leucocytes and platelets. A cubic millimetre of blood contains around 5 to 5.5 million RBCs.
Based on the presence or absence of granules in their cytoplasm, leucocytes are further grouped as granulocytes and agranulocytes. Neutrophils, eosinophils and basophils are called granulocytes while lymphocytes and monocytes are called agranulocytes. There are around 4,000 to 11,000 WBCs per cubic millimetre of blood. The chart displays the composition of different types of WBCs in blood.