Free Human Heart MCQs with Answers
70 Human Heart 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 human heart is a four chambered muscular pump that maintains double circulation through the pulmonary and systemic circuits. Questions cover atria, ventricles, valves, major blood vessels, the cardiac cycle, pressure changes, the conduction system and ECG, while distinguishing arteries and veins from the chambers that receive or eject blood.
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- A. carry deoxygenated blood only
- B. must collapse when empty
- C. must withstand and smooth out the high pressure of blood from the heart
- D. need to store lymph between meals
Explanation: Each heartbeat stretches the elastic walls, which then recoil and keep blood moving between beats, converting a pulsatile flow into a…
Correct answer: must withstand and smooth out the high pressure of blood from the heart- A. walls are unusually thick
- B. total cross sectional area is enormous
- C. internal pressure is the highest of any vessel
- D. diameter exceeds that of the aorta
Explanation: Although each capillary is microscopic, together they present a huge total area, so the same volume of blood spreads out and slows…
Correct answer: diameter exceeds that of the aorta- A. pulmonary artery
- B. pulmonary vein
- C. aorta
- D. coronary artery
Explanation: The pulmonary artery is the exception to the rule that arteries carry oxygenated blood, since it carries blood to the lungs to be…
Correct answer: pulmonary artery- A. carotid artery
- B. aorta
- C. femoral artery
- D. renal artery
Explanation: The aorta, about 2.5 cm in diameter, receives the entire output of the left ventricle and branches to every organ.
Correct answer: aorta- A. left ventricle
- B. left atrium
- C. right atrium
- D. aorta
Explanation: The venae cavae collect blood from the upper and lower body and deliver it to the right atrium, from where it passes to the right…
Correct answer: right atrium- A. aorta
- B. arteries
- C. arterioles
- D. venae cavae
Explanation: Pressure falls steadily through arteries, arterioles and capillaries as energy is lost to friction, reaching near zero in the great veins.
Correct answer: venae cavae- A. atherosclerosis
- B. arthritis
- C. anaemia
- D. haemophilia
Explanation: Plaques of cholesterol and debris narrow and stiffen arteries, raising blood pressure and predisposing to clots that cause heart attacks…
Correct answer: atherosclerosis- A. tonsils
- B. spleen
- C. thymus
- D. lymph node
Explanation: The spleen sits in the abdomen and acts on blood the way lymph nodes act on lymph, trapping pathogens and recycling old erythrocytes.
Correct answer: spleen- A. along the spinal cord
- B. in the thorax around the heart
- C. in the throat, guarding the entrances of the respiratory and digestive tracts
- D. inside the bone marrow
Explanation: Their position at the back of the mouth and nose lets them sample inhaled and swallowed material and mount early immune responses.
Correct answer: in the throat, guarding the entrances of the respiratory and digestive tracts- A. capillaries of the tissues
- B. aorta
- C. pulmonary vein
- D. subclavian veins near the neck
Explanation: The thoracic duct and right lymphatic duct empty lymph into the subclavian veins, restoring fluid and proteins that leaked from the…
Correct answer: subclavian veins near the neck- A. T lymphocytes mature
- B. red blood cells are produced
- C. antibodies are stored
- D. platelets are formed
Explanation: Immature lymphocytes from the bone marrow migrate to the thymus, where they learn to distinguish self from non self.
Correct answer: T lymphocytes mature- A. contains more red blood cells than blood
- B. has no red blood cells and less protein
- C. flows away from the heart through arteries
- D. contains no white blood cells
Explanation: Lymph is essentially filtered tissue fluid, so it lacks erythrocytes and is poorer in plasma proteins, though it carries lymphocytes.
Correct answer: has no red blood cells and less protein- A. they fill with excess tissue fluid
- B. bacteria dissolve inside them
- C. lymphocytes multiply rapidly inside them to fight the pathogen
- D. their valves close and trap lymph
Explanation: Trapped antigens trigger lymphocyte proliferation within the node, enlarging it and making it tender.
Correct answer: lymphocytes multiply rapidly inside them to fight the pathogen- A. thick muscular walls like arteries
- B. red blood cells
- C. pacemakers
- D. valves that keep the lymph moving in one direction
Explanation: Lymph flows under very low pressure, so valves prevent backflow while surrounding muscle contractions squeeze it onwards.
Correct answer: valves that keep the lymph moving in one direction- A. Vitamin A
- B. Vitamin K
- C. Vitamin C
- D. Vitamin D
Explanation: Vitamin K is required for synthesis of clotting factors II, VII, IX, and X in the liver.
Correct answer: Vitamin K- A. Prothrombin
- B. Thrombin
- C. Calcium
- D. Platelets
Explanation: Thrombin converts soluble fibrinogen to insoluble fibrin, forming the mesh of blood clots.
Correct answer: Thrombin- A. pulmonary trunk
- B. brain
- C. aorta
- D. body
Explanation: The right ventricle pumps deoxygenated blood through the pulmonary semilunar valve into the pulmonary trunk, which divides into the…
Correct answer: pulmonary trunk- A. pleura
- B. pericardium
- C. peritoneum
- D. epithelium
Explanation: The pericardium is the double-layered membranous sac surrounding the heart and contains lubricating fluid that reduces friction during…
Correct answer: pericardium- A. 60 to 100
- B. 70 to 100
- C. 50 to 100
- D. 80 to 100
Explanation: A normal resting adult human heart rate is generally about 60 to 100 beats per minute, reflecting the rate at which the sinoatrial node…
Correct answer: 60 to 100- A. 60 Times
- B. 70 Times
- C. 80 Times
- D. 85 Times
Explanation: A commonly taught comparison gives an average adult male heart rate of about 72 beats per minute and an adult female rate of about 80…
Correct answer: 80 Times