Tutor profile: Vijay S.
Subject: Biomedical Science
What is significance of ABO blood grouping system?
Out of some 30 blood grouping systems, ABO and Rhesus blood grouping systems are of the greatest significance to human. An individual's blood group is determined by the type of antigens present on the surface of red blood corpuscles (RBCs). ABO blood grouping system finds great importance in blood transfusion. Human body starts developing natural antibodies (anti-A and anti-B) against the ABO antigens from early childhood (after attaining 18 months of age), even before never being exposed to the other ABO antigens (from RBCs of blood of donar at the time of blood transfusion). On blood transfusion, the naturally occurring anti-A and anti-B antibodies in the recipient individual cause severe haemolytic reactions to the transfusion of incompatible RBCs of the donar. These haemolytic reactions are considered severe enough to cause death of the recipient individual. It is believed that children start producing natural ABO antibodies as a result of exposure to similar kind of carbohydrates in diet as present on the surface of ABO antigens of RBCs.
What is mutarotation?
The phenomenon of change in the rotational value of an optically active solution is known as mutarotation. Several carbohydrates including pentoses, hexoses and reducing disaccharides exhibit this phenomenon. An aqueous solution of α-D-Glucose, crystallised from water or aqueous solution at low temperature, has specific optical rotation of +112.2° (dextrorotatory) but when this aqueous solution is allowed to stand, then it's optical rotational value gradually changes with time and finally reaches an equilibrium value of +52.7°C. Similarly, the optical rotational value of aqueous solution of β-D-Glucose (crstallised from water above 98°C) has optical value of +18.7° but it gradually reaches an equilibrium value of 52.7°. It happens due to formation of an equilibrium mixture containing about one-third α-D-glucose and two-third β-D-glucose at 20°C. Similarly fructose and other carbohydrates also show mutarotation.
Explain the portal system in human.
Humans have Hepatic Portal System. It has great significance in our body. The blood which comes from elementary canal contains digested food like glucose, fatty acids and amino acids. The excess of glucose present in blood is converted into glycogen which is stored in the liver for later use. When an individual does not eat sufficient quantity of food, the glycogen is converted into glucose and is transferred to the blood circulatory system (blood stream) via hepatic veins (of hepatic portal system). In addition, harmful nitrogenous wastes like ammonia, generated as a result of catabolic reactions in the body, is converted into urea which is later removed from the body by kidneys. Thus, hepatic portal system detoxifies the blood of the harmful nitrogenous waste.
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