Free Circulation MCQs with Answers
695 Circulation MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The circulatory system covers the chambers, valves and conducting pathway of the human heart, along with the cardiac cycle and control of heartbeat. It compares arteries, veins and capillaries by structure and function, and explains how the lymphatic system returns tissue fluid, transports absorbed fats and supports immunity.
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Read the Circulation notesFree MDCAT chapter notes with key terms695 questions · page 8 of 35
- A. Right Atrium
- B. Left Atrium
- C. Right Ventricle
- D. Left Ventricle
Explanation: The right atrium is the part of the heart that receives deoxygenated blood from the whole body via the superior and inferior vena cava.
Correct answer: Right Atrium- A. The superior vena cava
- B. Aorta
- C. The inferior vena cava
- D. The four pulmonary veins
Explanation: The left atrium receives oxygenated blood from the four pulmonary veins (right/left superior and inferior).
Correct answer: The four pulmonary veins- A. More pressure than ventricles
- B. Same pressure as ventricles
- C. Less pressure than ventricles
- D. Less volume than ventricles
Explanation: When atria are filled with blood and ventricles are empty, atria have more pressure than ventricles.
Correct answer: More pressure than ventricles- A. Aorta
- B. Pulmonary arteries
- C. Pulmonary veins
- D. Vena cava
Explanation: The aorta carries oxygenated blood at the highest pressure, ~90 mmHg, from the left ventricle to systemic circulation.
Correct answer: Aorta- A. Strong muscular walls
- B. Narrow lumen
- C. Valves control direction of blood flow opposite to heart
- D. Valves control direction of blood flow towards heart
Explanation: All the veins transport blood to the heart.
Correct answer: Valves control direction of blood flow towards heart- A. Pancreatic duct
- B. Bile duct
- C. Thoracic duct
- D. Parotid duct
Explanation: The flow of lymph is always towards the thoracic duct. The thoracic duct is the largest lymphatic vessel in the body, and it is…
Correct answer: Thoracic duct- A. Renal vein
- B. Subclavian vein
- C. Pulmonary vein
- D. Jugular vein
Explanation: The pulmonary vein is the only vein in the human body that carries oxygenated blood, while all other veins carry deoxygenated blood.
Correct answer: Pulmonary vein- A. Blood
- B. Lymphatic vessels
- C. Lymph nodes
- D. Lymph
Explanation: Blood is not part of the lymphatic system because it has different functions and components.Blood is a fluid that circulates through the…
Correct answer: Blood- A. Subclavian artery
- B. Subclavian vein
- C. Iliac artery
- D. Iliac vein
Explanation: Lymph drains into the bloodstream via the subclavian veins, ensuring interstitial fluid returns to systemic circulation.
Correct answer: Subclavian vein- A. Blood
- B. Lymph
- C. Semen
- D. Amniotic fluid
Explanation: Lymph is a clear, colorless fluid that closely resembles blood plasma and is filtered by the lymph nodes.
Correct answer: Lymph- A. Left atrium and left ventricle
- B. Right atrium and left ventricle
- C. Left atrium and right ventricle
- D. Right ventricle and right ventricle
Explanation: A bicuspid valve has only two leaflets (flaps or cusps), instead of three.
Correct answer: Left atrium and left ventricle- A. 7.35
- B. 7.12
- C. 7.2
- D. 7.25
Explanation: The pH of human blood is within the range of 7.35 to 7.45 and is usually maintained at approximately 7.4.
Correct answer: 7.35- A. 0.8 sec
- B. 0.2 sec
- C. 0.4 sec
- D. 0.5 sec
Explanation: 0.8 seconds: This option is the correct answer. One complete heartbeat, which includes one systole (contraction) and one diastole…
Correct answer: 0.8 sec154. Pulse is found in:
- A. Arteries
- B. Capillaries
- C. Veins
- D. Both A and B
Explanation: The pulse is typically detected in arteries. Arteries are blood vessels that carry oxygenated blood away from the heart to various parts…
Correct answer: Arteries- A. Abdominal vein
- B. Jugular vein
- C. Subclavian vein
- D. Bile duct
Explanation: The lymphatic vessels of the body empty the lymph into the subclavian vein.
Correct answer: Subclavian vein- A. 7-8 L
- B. None of these
- C. 2-3 L
- D. 8-12 L
Explanation: Approximately 30 litres of fluid pass from the blood capillaries into interstitial space each day, whereas only 27 liters passes from the…
Correct answer: 2-3 L- A. Both have small bore
- B. Both have valves
- C. Both have low blood pressure
- D. Both are communicated
Explanation: This is the correct answer. Both lymph vessels and veins have one-way valves to prevent the backflow of fluid.
Correct answer: Both have valves- A. 0.008 sec
- B. 0.8 sec
- C. 8 sec
- D. 0.088 sec
Explanation: The cardiac cycle involves the complete contraction and relaxation of both the atria and ventricles and the cycle lasts for about 0.8…
Correct answer: 0.8 sec- A. Spleen, Lymph nodes
- B. Lymph nodes, Lymph nodes
- C. Spleen, Spleen
- D. Lymph nodes, Spleen
Explanation: Just as the lymph nodes filter lymph, the spleen filters blood, exposing it to macrophages and lymphocytes that destroy foreign particles…
Correct answer: Lymph nodes, Spleen- A. AV node
- B. SA node
- C. Purkinjie fibres
- D. Bundle of His
Explanation: SA node generates impulses that initiate heartbeats.
Correct answer: SA node