Prof. J.P.N. Mishra
Plasma is the liquid part of blood having approximately 91% water. The solvent ability of water enables the plasma to transport many types of substances. Nutrients absorbed in the digestive tract, such as glucose, amino acids, and minerals, are circulated to all body tissues. Waste products of the tissues, such as urea and creatinine, circulate through the kidneys and are excreted in urine. Hormones produced by endocrine glands are carried in the plasma to their target organs, and antibodies are also transported in plasma. Most of the carbon dioxide produced by cells is carried in the plasma in the form of bicarbonate ions (HC03). When the blood reaches the lungs, the CO, is re-formed, diffuses into the alveoli, and is exhaled. Also in the plasma are the plasma proteins. The clotting factors prothrombin, fibrinogen, and others are synthesized by the liver and circulate until activated to form a clot in a ruptured or damaged blood vessel. Albumin is the most abundant plasma protein. The liver synthesizes it. Albumin contributes to the colloid osmotic pressure of blood, which pulls tissue fluid into capillaries.
This is important to maintain normal blood volume and blood pressure. Other plasma proteins are called globulins. Alpha and beta globulins are synthesized by the liver and they act as carriers for molecules such as fats. The gamma globulins are antibodies produced by lymphocytes. Antibodies initiate the destruction of pathogens and provide us with immunity. Plasma also carries body heat (Guyton, 1982).
Along with these the plasma also contain some organic substance witch are essential for the formation, maintenance and growth of various tissues and fluids in the body.
