- It is slightly alkaline non-living intercellular substance which constitutes about 60% part of the blood.
- It is a pale yellow but transparent and clear fluid.
COMPOSITION OF PLASMA -
1. Water - Water alone forms about 90% to 92% ofthe plasma. Solids form about 8% of the plasma.
2. Mineral Salts- These are chlorides, bicarbonates, sulphates and phosphates of sodium, potassium, calcium, iron and magnesium. All salts constitute about 0.9% of plasma. Buffer of the blood is sodium bicarbonate.
3. Nutrients - These include glucose, fatty acids, phospholipids, cholesterol, fats, aminoacids, nucleosides, etc.
4. Plasma Proteins- They constitute about 7 to 8% part of plasma. These mainly include albumin, globulin, immu- noglobulin, prothrombin and fibrinogen.
5. Defence Compounds - Immunoglobulins which act as antibodies and some other substances, such as lysozyme (a polysaccharide) and properdin (a large protein) are always found in the plasma. They destroy bacteria, viruses and toxic substances that may enter into the blood from outside.
6. Excretory Substances - These include ammonia, urea, uric acid, creatine, creatinine, etc.
7. Dissolved Gases- Water of blood plasma contains oxygen, carbon dioxide and nitrogen in dissolved form. .
8. Anticoagulant - Blood plasma contains a conjugated polysaccharide, the heparin which prevents coagulation of blood inside blood vessels.
9. Hormones - These are secreted and released in blood by endocrine glands.
10. Vitamins and Enzymes - Different kinds of vitamins and enzymes are present in the blood plasma.