Assertion (A): | If the SA node does not function, or the impulse generated in the SA node is blocked before it travels down the electrical conduction system, the heart would stop. |
Reason (R): | No other part of the nodal tissue of the heart is capable of generating the impulse. |
In the light of the above statements choose the correct answer from the options given below:
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): | Lymph that enters the lymph vessels from the interstitial spaces usually does not flow backwards along the vessels. |
Reason (R): | Unlike the cardiovascular system, the lymphatic system is not closed and has no central pump. |
In the light of the above statements choose the correct answer from the options given below:
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
Assertion (A): | The increased efficiency of the double circulatory system in mammals and birds is thought to have been important in the evolution of endothermy. |
Reason (R): | Crocodile, a reptile, is not an endotherm in spite of having a four chambered heart. |
In the light of the above statements choose the correct answer from the options given below:
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): | The left ventricle pumps the blood with greater force than the right ventricle. |
Reason (R): | The left ventricle pumps more blood than the right ventricle during each contraction. |
In the light of the above statements choose the correct answer from the options given below:
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
Certain factors that can initiate coagulation of blood can be released by:
I: | Platelets in the blood |
II: | Tissues at the site of injury |
III: | Liver |
1. | I and II only | 2. | I and III only |
3. | II and III only | 4. | I, II and III |
All terrestrial vertebrates possess:
1. A muscle or elastic membrane to increase thoracic volume
2. A renal portal system
3. A skin that does allow diffusion of gases
4. At least a three chambered heart
A tricuspid valve will prevent flow of blood from:
1 Right atrium to right ventricle
2. Right ventricle to right atrium
3. Left atrium to left ventricle
4. Left ventricle to left atrium
Purkinje fibers are:
1. | Intrinsic neural fibers in the ventricles |
2. | Muscle fibers that interconnect SA node and AV node |
3. | Muscle fibers that are distributed in the ventricular musculature |
4. | Neural fibers that spread the impulse throughout the ventricular muscle mass |
All the following statements regarding joint diastole phase of the cardiac cycle are correct except:
1. | All chambers are in a relaxed state |
2. | The AV valves may remain closed in the initial period |
3. | Ventricles get filled in the later part |
4. | Semilunar valves remain open |
A trained athlete can achieve a maximal cardiac output of:
1. | 5 – 10 L/min | 2. | 15 – 20 L/min |
3. | 25 – 30 L/min | 4. | 55 – 60 L/min |