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 5 of 35
- A. Stroke volume
- B. Cardiac output
- C. Blood pressure
- D. Blood flow
Explanation: Blood pressure is the force exerted by circulating blood against the walls of blood vessels, usually expressed in mmHg.
Correct answer: Blood pressure- A. Thrombus
- B. Embolus
- C. Atheroma
- D. Hematoma
Explanation: An atheroma is a fatty, cholesterol-rich plaque in an arterial wall, not a blood clot.
Correct answer: Atheroma- A. Myocardial infarction
- B. Cerebral infarction
- C. Cerebral Hemorrhage
- D. Thromboembolism
Explanation: Cerebral haemorrhage is bleeding caused by rupture of a blood vessel in or around the brain.
Correct answer: Cerebral Hemorrhage- A. Superior vena cava
- B. Inferior vena cava
- C. Hepatic vein
- D. Pulmonary vein
Explanation: The pulmonary vein carries oxygen-rich blood from the lungs to the left atrium, making it the exception among these veins.
Correct answer: Pulmonary vein- A. 2.8 Billion
- B. 3.7 Billion
- C. 4.2 Billion
- D. Infinite
Explanation: A typical estimate is about 70 beats/minute x 60 minutes/hour x 24 hours/day x 365 days/year x 70 years = 2,574,720,000 beats, or about…
Correct answer: 2.8 Billion- A. 1
- B. 2
- C. 3
- D. 4
Explanation: One cardiac cycle has three main stages: atrial systole, ventricular systole, and joint diastole.
Correct answer: 3- A. Bradycardia
- B. Tachycardia
- C. Braditachycardia
- D. Non of these
Explanation: Bradycardia means an abnormally slow heart rate, commonly defined in adults as fewer than 60 beats per minute at rest.
Correct answer: Bradycardia- A. Bradycardia
- B. Tachycardia
- C. Trachybradycardia
- D. Non of these
Explanation: Tachycardia is an abnormally rapid heart rate, often described in adults as more than 100 beats per minute at rest.
Correct answer: Tachycardia- A. The ventricles are fully contracted
- B. The ventricles start to relax
- C. The bicuspid and tricuspid valves suddenly close
- D. The semilunar valves are closed
Explanation: The “lub” sound is produced when the atrioventricular valves, the bicuspid and tricuspid valves, suddenly close at the beginning of…
Correct answer: The bicuspid and tricuspid valves suddenly close- A. Atrial systole
- B. Ventricular systole
- C. Atrial diastole
- D. Ventricular diastole
Explanation: The QRS complex records ventricular depolarisation, which initiates ventricular contraction or ventricular systole.
Correct answer: Ventricular systole- A. Opening of inlet valve
- B. Closure of inlet valve
- C. Opening of outlet valve
- D. Closure of outlet valve
Explanation: The lubb sound occurs when the atrioventricular, or inlet, valves close at the beginning of ventricular systole.
Correct answer: Closure of inlet valve- 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- A. pulmonary trunk
- B. brain
- C. aorta
- D. None of these
Explanation: The right ventricle pumps deoxygenated blood through the pulmonary semilunar valve into the pulmonary trunk, which carries it toward the…
Correct answer: pulmonary trunk- A. 150 Days
- B. 120 Days
- C. 80 Days
- D. 100 Days
Explanation: Red blood cells circulate for about 120 days before ageing changes their membranes and they are removed mainly by the spleen and liver.
Correct answer: 120 Days- A. 1
- B. 2
- C. 3
- D. 4
Explanation: An octopus has three hearts: two branchial hearts pump blood to the gills, while one systemic heart pumps oxygenated blood to the rest of…
Correct answer: 3- A. Brain
- B. Pulmonary Artery
- C. Aorta
- D. Lungs
Explanation: The left ventricle pumps oxygenated blood into the aorta, which distributes it through the systemic circulation to the body.
Correct answer: Aorta- A. Fishes
- B. Amphibians
- C. Reptiles
- D. Mammals
Explanation: Fish have a two-chambered heart and a single circulatory circuit: heart to gills, gills to body tissues, and body tissues back to the…
Correct answer: Fishes