Blood is a viscous fluid of bright red color, heavier
than water and slightly alkaline. It consists of two components.
The liquid part is called plasma, and the large number of
cells is called blood corpuscles suspended in the plasma.
(a) Plasma : It is a straw-colored fluid
consisting of the following chemicalonents:
(1) 90% of water.
(2) 7% of plasma proteins like serum albumin,
serum globulin and fibrinogen.
(3) 3% of remaining substances, such as
(i) Nutrients like glucose, amino acids and
(ii) Inorganic salts like bicarbonates of sodium,
potassium, calcium and magnesium.
(iii) Organic compounds like enzymes, hormones,
antibodies, antitoxins and heparin, etc.
( iv) Gases like oxygen, carbon dioxide and
(v) Waste materials like urea, uric acid, etc.
The composition of plasma is altered in tissues
and controlled by organs like the liver and the kidneys.