NEET PG The Cardiovascular System: Blood — practice questions — page 5

1. More than 50 antigens have been identified on erythrocyte membranes. 2. Only two groups matter most for patient harm, the ABO group and the Rh group. 3. Exactly two would confuse the number of clinically important groups with the number of antigens known. 4. Dozens of Rh antigens alone have been identified, which already rules out any answer as low as two. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 18 "The Cardiovascular System: Blood", section 18.6 Blood Typing_

1. The ABO name uses three letters but designates the presence or absence of only two antigens, A and B. 2. Both of those antigens are glycoproteins. 3. Antigens in general are usually large proteins, though they may also be carbohydrates, lipids or nucleic acids. 4. For the ABO group specifically the answer is the glycoprotein, so the broader possibilities are distractors here. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 18 "The Cardiovascular System: Blood", section 18.6 Blood Typing_

1. An antibody attacks what the body reads as nonself. 2. This patient carries the A antigen, so A is self and cannot be attacked. 3. The B antigen is absent from these erythrocytes, so B is nonself. 4. The ABO group is unusual in that the antibody is preformed, without any prior exposure to incompatible blood. 5. A type A individual therefore has preformed anti-B antibodies circulating in the plasma. 6. Anti-A would agglutinate the patient's own cells, which is why that option is self-defeating. 7. Carrying both antibodies belongs to type O and carrying neither belongs to type AB, so each of those options names a different type. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 18 "The Cardiovascular System: Blood", section 18.6 Blood Typing_