Question

Given below are four statements (i-iv) regarding human blood circulatory system.
i. Arteries are thick-walled and have narrow lumen as compared to veins.
ii. Angina is acute chest pain when the blood circulation to the brain is reduced.
iii. Persons with blood group AB can donate blood to. any person with any blood group under ABO system.
iv. Calcium ions play a very important role in blood clotting.
Which two of the above statements are correct?

• A. i and iv
• B. i and ii
• C. ii and iii
• D. iii and iv

Answer 1

The correct option is A i and iv

i. Arteries have thick, elastic walls and narrow lumen while veins have thinner, scarcely elastic walls and wide lumen.

ii. Angina Pectoris is a pain in the chest due to deprived oxygen the heart muscle experience constricting pain. This is not a fatal condition and the pain passes off quickly.

iii. Persons with blood group AB is a universal recipients. It has both the antigens A and B but no bodies.

iv. During clot, Thromboplastin helps in the formation of an enzyme prothrombinase. This enzyme inactivates heparin and it also converts the inactive plasma protein prothrombin into its active form, thrombin. Both changes require calcium ions.

So, the correct answer is 'i and iv'.