MCQs on Double Circulation for NEET 2020

Double circulation is when blood takes two routes – one to supply oxygenated blood and the other when deoxygenated blood is supplied back to the heart. In humans, the circulatory system comprises three key elements – the heart, blood and blood vessels. The human circulatory system is known as a double circulatory system as blood passes through the heart not once but twice for every circuit/cycle. While the right side pumps to send deoxygenated blood to the lungs where it joins to be supplied with oxygen and is returned back to the heart. The left side pumps in oxygen-rich blood, newly supplied all through the body which is returned to the heart in a deoxygenated state.

1. Identify the correct statement

(a) Double circulation is characteristic of all vertebrates

(b) Volume of blood in pulmonary circulation is more than the volume of blood in systemic circulation at any instant

(c) blood pressure in pulmonary circulation is less than that of the systemic circulation

(d) a double aortic arch is seen in birds and mammals

Answer: (c)

2. The hepatic portal vein drains blood to the liver from

(a) stomach

(b) heart

(c) intestine

(d) kidneys

Answer: (c)

3. Identify the incorrect statement

(a) occurs only in mammals

(b) occurs in all vertebrates

(c) is composed of systemic circulation

(d) is composed of pulmonary circulation

Answer: (b)

4. Pick the most appropriate statement(s) as part of explanation for this statement – “Adult human RBCs are enucleate”.

I. Their internal space is available for oxygen transport

II. They are somatic cells

III. They do not need to reproduce

IV. They do not metabolise

(a) Only (I)

(b) Only (II)

(c) (I), (III) and (IV)

(d) (III) and (IV)

Answer: (a)

5. Blood pressure in the pulmonary artery is

(a) same as that in the aorta

(b) less than that in venae cavae

(c) more than that in the carotid

(d) more than that in the pulmonary vein

Answer: (d)

6. A stethoscope is used by doctors for cardiac auscultation. The second sound of each cardiac cycle is heard when

(a) AV node receives signal from SA node

(b) Semilunar valves close down after the blood flows into vessels from ventricles

(c) AV valves open up

(d) Ventricular walls vibrate due to gushing in of blood from atria

Answer: (b)

7. Blood pressure is maximum in mammalian aorta during

(a) diastole of the right ventricle

(b) systole of the left atrium

(c) diastole of the right atrium

(d) systole of the left ventricle

Answer: (d)

8. A patient admitted to the hospital with myocardial infarction is immediately administered with

(a) Streptokinase

(b) Statins

(c) Cyclosporin – A

(d) Penicillin

Answer: (a)

9. Systemic circulation in the cardiac system refers to

(a) carry red oxygenated blood

(b) carry blood to the left side of the heart

(c) carry blood to the right side of the heart

(d) carry oxygenated blood from lungs to heart

Answer: (c)

10. Oxygenated blood in the cardiac system

(a) leaves from right side of the heart

(b) leaves from left side of the heart

(c) enters lungs from heart

(d) does not leave the lungs

Answer: (b)

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