|
The components of the closed circulatory system in man are:
- A fluid that can carry all the materials to be transported (blood)
- A pumping organ that can push the fluid through the body - as time taken is important (heart)
- Many tubes through which the fluid can flow through the body (blood vessels)
It is a red coloured, viscous, alkaline (pH about 7.4) fluid flowing through the body of higher animals. The adult human body consists of 5-6 litres of blood. It has two components:
- Fluid plasma
- Solid formed elements
The elements include corpuscles and platelets.
It forms about 55% of the blood (about 3 litres). Its composition is as follows:
Water (92%)
Soluble components
The soluble components are:
Proteins (7%) - includes hormones, enzymes, globulin antibodies, albumin and fibrinogen. (Blood plasma without fibrinogen and other clotting factors is called Serum and is a yellow watery fluid).
Nutrients - include glucose, amino acids, fatty acids and glycerol
Metabolic Substances - include vitamins, lactic acid, urea and uric acid (non-protein nitrogenous substances - NPN)
Inorganic Ions (0.9%) - include sodium, potassium, calcium, magnesium, chlorine and radicals like sulphate, phosphate, etc.
Pigments - include small amounts of bilirubin, carotenes, etc. that give the plasma its characteristic yellow colour.
- Maintains osmotic pressure and viscosity of the blood
- Helps in transport of various substances like the hormones, enzymes, etc.
- Acts as a protein reservoir
- Helps in clotting of blood
- Helps in regulating body temperature
| 
