Biology BLOOOD GROUPS

### KEY TOPICS

star Blood Groups
star ABO Grouping
star Rh Grouping

### BLOOD GROUPS

● color{violet}("Blood of human") beings differ in certain aspects though it appears to be similar.

● Various types of grouping of color{violet}("blood") has been done.

● Two such groupings – the color{brown}("ABO and Rh") – are widely used all over the world.

### ABO GROUPING

● color{violet}("ABO grouping") is based on the presence or absence of color{brown}("two surface antigens") (chemicals that can induce immune response) on the color{violet}("RBCs") namely color{brown}("A and B.")

● Similarly, the color{violet}("plasma") of different individuals contain two natural antibodies (proteins produced in response to antigens).

● During color{violet}("blood transfusion"), any blood cannot be used; the blood of a donor has to be carefully matched with the blood of a recipient before any color{violet}("blood transfusion") to avoid severe problems of clumping (destruction of RBC).

● From the above mentioned table it is evident that group color{violet}("‘O’ blood") can be donated to persons with any other blood group and hence color{violet}("‘O’ group") individuals are called color{brown}("‘universal donors’.")

● Persons with color{violet}("‘AB’ group") can accept blood from persons with color{violet}("AB") as well as the other groups of color{violet}("blood.")

● Therefore, such persons are called color{brown}("‘universal recipients’")

### RH GROUPING

● Another antigen, the color{brown}("Rh antigen") similar to one present in color{brown}("Rhesus monkeys") (hence Rh), is also observed on the surface of RBCs of majority (nearly 80 %) of humans.

● Such individuals are called color{brown}("Rh positive") (Rh+ve) and those in whom this antigen is absent are called color{violet}("Rh negative (Rh-ve).")

● An color{violet}("Rh-ve") person, if exposed to color{violet}("Rh+ve blood"), will form specific antibodies against the Rh antigens.

● Therefore, color{violet}("Rh group") should also be matched before transfusions.

● A special case of color{brown}("Rh incompatibility") (mismatching) has been observed between the color{violet}("Rh-ve blood") of a pregnant mother with color{violet}("Rh+ve blood") of the color{violet}("foetus.")

● color{violet}("Rh antigens") of the foetus do not get exposed to the color{violet}("Rh-ve blood ")of the mother in the first pregnancy as the two bloods are well separated by the color{violet}("placenta.")

● However, during the delivery of the first child, there is a possibility of exposure of the color{violet}("maternal blood") to small amounts of the color{violet}("Rh+ve blood") from the foetus.

● In such cases, the mother starts preparing antibodies against color{violet}("Rh in her blood").

● In case of her subsequent pregnancies, the color{brown}("Rh antibodies") from the mother color{violet}("(Rh-ve)") can leak into the blood of the color{violet}("foetus (Rh+ve)") and color{violet}("destroy the foetal RBCs").

● This could be fatal to the color{violet}("foetus") or could cause severe color{violet}("anaemia") and jaundice to the baby.

● This condition is called color{brown}("𝘦𝘳𝘺𝘵𝘩𝘳𝘰𝘣𝘭𝘢𝘴𝘵𝘰𝘴𝘪𝘴 𝘧𝘰𝘦𝘵𝘢𝘭𝘪𝘴.")

● This can be avoided by administering color{brown}("anti-Rh antibodies") to the mother immediately after the delivery of the first child.