Blood group
BLOOD GROUP
ABO –Blood grouping
Blood differs from person to person due to the presence of various proteins/factors in the blood.Over 12 systems developed to describe type of blood.Most accepted system is ABO based on naturally occurring antigens on membranes of RBC (Landsteiner, 1991).Antigens A and B are inherited as dominant genes.
Four Types of Blood
Type A: 42% Accepts A and O
Type B: 10% Accepts B and O
Type AB: 3% Accepts AB and O
Type O: 45% Universal Donor
RH Factor = is the + and – of the blood
Blood group is named after the type of antigen on RBC membrane.Blood plasma contain (or may not) antibodies that can react with antigens A and B.Plasma does not contain antibodies against the antigens on its own RBC. Plasma contain antibodies against antigen A or B if not present on its RBC.Mixture of different types of blood →agglutination may occur –antibody-antigen reaction.Blood typing (cross-matching test) before blood transfusion is essential.
Blood Genotype Group Phenotype Antigen on RBC Antibodies
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Rh System
1940 Landsteiner described the Rh –Rhesus monkeys –factor/antigen on RBC in addition to the ABC antigen.85% of people have the antigen Rh+ Blood does not contain anti Rh antibodies, but anti Rh antibodies can appear in the blood of Rh-person if Rh+ RBC enters their blood stream through blood transfusion or during pregnancy.In blood typing, the presence of A, B, and O antigens plus the presence or absence of the Rh-factor determine a person’s specific blood type, such as A-positive, B-negative, and so on.
REFERENCES
•Vander,
A., Sherman, J., and Luciano, D. (2004) Human Physiology: The Mechanism of Body Function. McGraw-Hill.
•Hilderbrand, M. (1982) Analysis of Vertebrate Body. John Wiley and Sons.
•Bloom,
M.D., and D.W. Fawcett (1975) A Textbook of
Histology, W.B. Saunders.
•Hoar,
W, S. (1983) General and Comparative Physiology, Prentice-Hall.
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