They are absolutely essential to the blood and to the normal functioning of the body tissues. Without calcium compounds blood cannot clot in a wound.
Organic components of the plasma: The most important organic components of the blood plasma are a variety of complex plasma proteins such as the fibrinogens, the albumins and the globulins.
The globulins exist in on”, ?1-, ?2-, ?- and y-globulins. The average normal concentrations of the main plasma proteins in g per 100 ml are:
Albumin, 4 8; globulins, 2-3; fibrinogen, 0 3.
Thus, the albumins are present in the greatest concentration and they contribute most to the osmotic pressure.
The fibrinogens are essential for the clotting of the blood and the globulins generally called serum globulins, are protein antibodies that provide immunity to various disease.
These plasma proteins also act as efficient buffers and so help to maintain the pH of the blood at an almost constant level very close to neutrality.
A number of proteins with specific physiological-functions have been isolated from the globulin fraction by electrophoresis and these are prothombin, plasma thromboplastin, isohaemagglutinins angio- tensinogen, immune globulins and anterior pituitary hormones.
In addition to those plasma proteins certain, other organic substances are also found in the plasma which may be classified under following heads:
1. Nutrients and catalysts:
These include glucose, fats, amino acid, vitamins and hormones.
2. Waste products:
These include urea and other nitrogenous products produced after the breakdown of ingested proteins or cellular proteins from cells worn-out or destroyed by infection.