Assertion (A): The neural signals through the sympathetic nerves increase the heart-beat, thereby decreasing the cardiac output.
Reason (R): Adrenalin secretion drastically decrease cardiac output.
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.
Subtopic: Â Regulation of Cardiac Activity |
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Assertion (A): All vertebrate have hepatic portal system.
Reason (R) All animals have hepatic portal system.
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.
Subtopic: Â Human Heart: Double Circulation |
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Assertion (A): In joint diastole, all the four chambers of heart are in relaxed state.
Reason (R): The atrio-ventricular valves are open and the semilunar valves are closed at this stage.
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.
Subtopic: Â Human Heart: Cardiac Cycle |
 64%
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Assertion (A): A symptom of acute chest pain is called 'Angina pectroris'.
Reason (R): In this condition heart do not pump blood effectively to meet body needs.
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.
Subtopic: Â Atherosclerosis, Hypertension & Ventricular Fibrillation |Â DISORDERS OF CIRCULATORY SYSTEM |
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Assertion (A): Lymph is called the 'middle man' of body.
Reason (R): Exchange of nutrients, gases and other materials between blood and the cells always occur through this fluid.
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.
Subtopic: Â Lymph |
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Assertion (A): If an individual stands immobile for a long time, it leads to accumulation of fluids in the leg tissues and swelling in feet.
Reason (R): Contraction of muscles compresses the veins to move the blood inside them.
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.
Subtopic: Â Blood: General Description & RBC: Part 1 |Â Blood: General Description & RBC: Part 2 |Â Human Heart: Double Circulation |
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Assertion (A): The cardiac impulse which originates from SA node in human heart cannot spread directly from atria to ventricles.
Reason (R): In human heart there is no continuity between cardiac muscle fibres of atria and those of ventricles except AV bundles.
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.
Subtopic: Â Human Heart: Cardiac Cycle |Â Rhythmic Excitation of Human Heart: Part 1 |Â Rhythmic Excitation of Human Heart: Part 2 |
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What prevents the atria and the ventricles from contracting at the same time?
1. Pacemaker cells located in the atria fire before the pacemaker cells in the ventricles.
2. It takes time for epinephrine to diffuse from the atria to the ventricles to trigger contraction
3. The electrical signal generated in the right atrium is delayed at the AV node before passing to the ventricles.
4. The Na+ channels responsible for initiating ventricular contraction are inactivated and need to return to activated configuration to the electrically stimulated.
Subtopic: Â Human Heart: Gross Anatomy |Â Human Heart: Cardiac Cycle |Â Rhythmic Excitation of Human Heart: Part 1 |Â Rhythmic Excitation of Human Heart: Part 2 |
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