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Given below are four statements (a–d) regarding human blood circulatory system
(a) Arteries are thick-walled and have narrow lumen as compared to veins
(b) Angina is acute chest pain when the blood circulation to the brain is reduced
(c) Persons with blood group AB can donate blood to any person with any blood group under ABO system
(d) Calcium ions play a very important role in blood clotting
Which two of the above statements are correct?
(a) Arteries are thick-walled and have narrow lumen as compared to veins
(b) Angina is acute chest pain when the blood circulation to the brain is reduced
(c) Persons with blood group AB can donate blood to any person with any blood group under ABO system
(d) Calcium ions play a very important role in blood clotting
Which two of the above statements are correct?
A
(a) & (d)
B
(a) & (b)
C
(b) & (c)
D
(c) & (d)
Detailed Solution
(a) is correct: arteries have a thick tunica media and a narrow lumen because they carry blood at high pressure; veins have thinner walls and a wider lumen.
(b) is wrong: angina (angina pectoris) is acute chest pain that appears when not enough oxygen reaches the heart muscle, i.e., when blood flow to the heart, not the brain, is reduced.
(c) is wrong: persons with blood group AB can accept blood from all groups (universal recipients); the universal donors are persons with group O.
(d) is correct: calcium ions play a very important role in clotting; they are needed for the formation of thrombokinase and the conversion of prothrombin into thrombin.
Hence the correct statements are (a) and (d).
(b) is wrong: angina (angina pectoris) is acute chest pain that appears when not enough oxygen reaches the heart muscle, i.e., when blood flow to the heart, not the brain, is reduced.
(c) is wrong: persons with blood group AB can accept blood from all groups (universal recipients); the universal donors are persons with group O.
(d) is correct: calcium ions play a very important role in clotting; they are needed for the formation of thrombokinase and the conversion of prothrombin into thrombin.
Hence the correct statements are (a) and (d).