Plasma is a pale yellow liquid and contains 90% water; the corpuscles float in it.
Clotting of Blood:
The plasma consists of fibrinogen and serum. On exposure, fibrinogen is converted into fibrin, which being insoluble in serum forms a network, in the meshes of which blood corpuscles get entangled, and clot is formed. In this way bleeding is stopped automatically after some time.
Functions of Blood:
(a) It supplies oxygen to various organs of the body.
(b) It removes the waste products of the body,
(c) It supplies food to various organs of the body,
(d) It resists the attack of germs,
(e) It carries the secretions of ductless glands (hormones) to different organs.
(f) It maintains the temperature of the body.
It is the introduction of the blood of similar composition and nature into a person suffering from bloodlessness. Blood donation is painless and one can donate 250 c.c. or 8% of blood at a time, It was first introduced by Landsteiner.
Blood Banks have been set up in all big cities where people can offer their blood, which is stored to be used in case of a an emergency, such as accidents causing loss of blood, anaemic persons, etc.
Dr. Costelio and later Dr. Moss in 1910 were responsible for classification of blood; the blood groups are AB, A, B, and O. The blood of colder climate people is usually AB, or A, and that of the warmer climate ones is B or O. Patients must be given transfusion of blood of their own group with the exception of Group O, which is universal, donor.