Circulation

Circulation MDCAT MCQs with answers

63 past paper MCQs from Biology unit 11, Circulation, across 4 topics. They are arranged topic by topic; bigger topics show a sample here and link to their full set and to study notes. Tap “Show answer” for the correct option and a short solution.

Practise as a quiz

Blood Vessels

1.The descending aorta bifurcates into two vessels which on further division form the femoral artery that supplies blood to the muscles of the legs. These two vessels are the: (MDCAT 2023)

  1. iliac veins
  2. iliac arteries
  3. temporal arteries
  4. sciatic arteries
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Correct answer: (b) iliac arteries

The aorta ends by dividing into the two common iliac arteries.

2.Which of the following blood vessels have lowest blood velocity with correct reason for low blood velocity? (UHS MDCAT 2025)

  1. Arteries: Due to thick walls
  2. Capillaries: due to highest overall cross-sectional area
  3. Veins: due to blood flow against the gravity
  4. Capillaries: Due to two-way blood flow in capillaries
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Correct answer: (b) Capillaries: due to highest overall cross-sectional area

The capillary bed has by far the largest total cross-section, and flow is slowest where the section is greatest.

3.Blood flow in vessels least depends on: (NUMS MDCAT 2025)

  1. Total cross sectional area of vessels
  2. Blood pressure
  3. Skeletal muscle contraction
  4. Heart beat
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Correct answer: (c) Skeletal muscle contraction

Muscle contraction helps the venous return, but the flow itself is set by the heart, the pressure and the vessel bore.

All 17 Blood Vessels MCQs → Blood Vessels notes →

Human Heart

4.The heart is surrounded by a tough, inelastic double membranous covering called: (KMU MDCAT 2025)

  1. Pleura
  2. Peritoneum
  3. Pericardium
  4. Meninges
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Correct answer: (c) Pericardium

The pericardium is the double bag around the heart, with fluid between its layers.

5.Identify the location of mitral valve in human heart: (NUMS MDCAT 2025)

  1. Between right ventricle and pulmonary trunk
  2. Between left ventricle and aorta
  3. Between right atrium and right ventricle
  4. Between left atrium and left ventricle
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Correct answer: (d) Between left atrium and left ventricle

The mitral, or bicuspid, valve guards the opening between the left atrium and the left ventricle.

6.Atrial walls are thinner as compared to ventricles because: (SZABMU MDCAT 2025)

  1. Atria are small in size
  2. Atria are present above the ventricles
  3. Atria has to force blood into the ventricles which lie very close to them
  4. Blood enters into the atria by osmosis
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Correct answer: (c) Atria has to force blood into the ventricles which lie very close to them

An atrium has only to push blood into the ventricle just below, so it needs little muscle.

All 13 Human Heart MCQs → Human Heart notes →

Lymphatic System

7.The lymphatic vessels of the body empty the lymph into the blood stream at the: (MDCAT 2022)

  1. abdominal vein
  2. jugular vein
  3. subclavian vein
  4. thoracic duct
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Correct answer: (c) subclavian vein

The thoracic duct is the vessel that carries it, and it drains into the subclavian vein.

8.The final destination of lymph is the: (MDCAT 2023)

  1. lymph node
  2. lymphoid organs
  3. subclavian vein
  4. spleen
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Correct answer: (c) subclavian vein

The thoracic duct returns lymph to the blood at the subclavian vein.

9.The first consequence of lymphatic blockage in tissues is: (UHS MDCAT 2025)

  1. Deficiency of oxygen
  2. Loss of nerve signals
  3. Drop in blood pressure
  4. Excess fluid accumulation in tissue
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Correct answer: (d) Excess fluid accumulation in tissue

Lymph vessels drain the tissue fluid, so a blockage leaves it to collect in the tissue as oedema.

All 18 Lymphatic System MCQs → Lymphatic System notes →

Cardiac Cycle and Phases of the Heartbeat

10.Which phase of the cardiac cycle is characterized by the opening of semilunar valves? (KMU MDCAT 2025)

  1. Atrial systole
  2. Atrial diastole
  3. Ventricular systole
  4. Ventricular diastole
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Correct answer: (c) Ventricular systole

The semilunar valves open when the ventricles contract and drive blood into the arteries.

11.Which part of the heart's conducting system delays the impulse from atria to the ventricles? (KMU MDCAT 2025)

  1. Sino-atrial node
  2. Atrio-ventricular node
  3. Purkinje fibers
  4. Atrio-ventricular valves
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Correct answer: (b) Atrio-ventricular node

The atrioventricular node holds the impulse back long enough for the atria to empty first.

12.The heartbeat sound “LUB” is produced on closure of (KMU MDCAT 2025)

  1. Aortic valve
  2. Atro-ventricular valves
  3. Pulmonary valves
  4. Semilunar valves
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Correct answer: (b) Atro-ventricular valves

The first sound is the shutting of the atrioventricular valves at the start of ventricular systole.

All 15 Cardiac Cycle and Phases of the Heartbeat MCQs → Cardiac Cycle and Phases of the Heartbeat notes →

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