There are more than 30 antigens on the surface of blood cells that give rise to different blood groups.
ABO Grouping ABO grouping is based on the presence or absence of two surface antigens on the RBCs namely. A and B. The plasma of different individuals contain two natural antibodies. The distribution of antigen and antibody in the four groups of blood, A , $\mathrm{AB}, \mathrm{B}$ and O are explained above in the table.
Human ABO Blood Groups and their Compatibility
| Blood Group | Genotype | Antigens on Red Blood Corpuscles | Antibodies in Blood Plasma | Donor | Recipient |
|---|---|---|---|---|---|
| A | $\mathrm{I}^A \mathrm{I}^A$ or $\mathrm{I}^A \mathrm{I}^O$ | A | b | A, AB | A, O |
| B | $\mathrm{I}^B \mathrm{I}^B$ or $\mathrm{I}^B \mathrm{I}^O$ | B | a | B, AB | B, O |
| AB | $\mathrm{I}^{\mathrm{A}} \mathrm{I}^8$ | AB | None | AB | AB, A, B, O |
| O | $\mathrm{I}^{\mathrm{O}} \mathrm{I}^O$ | None | a, b | AB, A, B, O | O |
From the above table it is evident that group ' O ' blood can be donated to persons with any other blood group and hence 'O' group individuals are called 'Universal donors'. Person with 'AB' blood can accept blood from persons with AB, as well as the other groups of blood. Therefore, such persons are called 'Universal recipients'.
Write short note on the following.
(a) Hypertension (b) Coronary Artery Disease
(a) Hypertension The high blood pressure can harm heart, brain kidneys and eyes. High blood pressure is most common disease affecting the heart and blood vessels, Blood pressure is considered normal at 120/80. When it goes beyond 140 mm Hg and 90 mm Hg it is called hypertension or high blood pressure.
Causes of Hypertension
(i) Blockage in the coronary heart vessels.
(ii) Tobacco smoking speeds up heart rate. It constrict blood vessels and raises blood pressure.
(b) Coronary Artery Disease (CAD) It is caused due to the deposition of fatty substances on the arterial wall causing atherosclerotic plaques. The lumen of artery decreases, thus obstructing the blood flow and sometimes completely blocks the artery resulting into thus, heart attack.
The diagrammatic presentation of heart with labelled SAN, AVN, AV bundles bundle of His and purkinje fibres in heart is show as follows
