Blood circulation through the heart MCQs With Answer

Introduction

Understanding blood circulation through the heart is essential for B. Pharm students preparing for pharmacology and clinical therapeutics. This concise overview links cardiac chambers, valves, coronary circulation, pulmonary and systemic pathways, and the cardiac cycle with key physiological terms such as stroke volume, cardiac output, preload, afterload, contractility, and conduction system. Emphasis on pressure gradients, valve mechanics, fetal shunts, and coronary perfusion clarifies how drugs influence hemodynamics and cardiac tissue delivery. Mastery of these concepts supports rational dosing, prediction of drug effects, and recognition of cardiotoxicity. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which sequence correctly represents the flow of blood through the heart?

• Superior vena cava → Right atrium → Tricuspid valve → Right ventricle → Pulmonary valve → Pulmonary artery → Lungs → Pulmonary veins → Left atrium → Mitral valve → Left ventricle → Aortic valve → Aorta
• Aorta → Left ventricle → Mitral valve → Left atrium → Pulmonary veins → Lungs → Pulmonary artery → Right ventricle → Tricuspid valve → Right atrium → Superior vena cava
• Right atrium → Left atrium → Right ventricle → Left ventricle → Pulmonary artery → Pulmonary veins → Aorta
• Left atrium → Left ventricle → Pulmonary trunk → Lungs → Pulmonary veins → Right atrium → Right ventricle → Aorta

Correct Answer: Superior vena cava → Right atrium → Tricuspid valve → Right ventricle → Pulmonary valve → Pulmonary artery → Lungs → Pulmonary veins → Left atrium → Mitral valve → Left ventricle → Aortic valve → Aorta

Q2. Which valve separates the right atrium from the right ventricle?

• Aortic valve
• Pulmonary valve
• Tricuspid valve
• Mitral valve

Correct Answer: Tricuspid valve

Q3. The valve between the left atrium and left ventricle is called:

• Tricuspid valve
• Mitral (bicuspid) valve
• Aortic semilunar valve
• Pulmonary semilunar valve

Correct Answer: Mitral (bicuspid) valve

Q4. What is the primary function of chordae tendineae?

• Conduct electrical impulses between atria and ventricles
• Prevent atrioventricular valve prolapse during ventricular systole
• Provide structural support to semilunar valves
• Regulate coronary blood flow

Correct Answer: Prevent atrioventricular valve prolapse during ventricular systole

Q5. Coronary arteries primarily originate from which anatomical structure?

• Left ventricle myocardium
• Aortic sinuses (sinuses of Valsalva)
• Pulmonary trunk
• Superior vena cava

Correct Answer: Aortic sinuses (sinuses of Valsalva)

Q6. The coronary sinus drains venous blood from the myocardium into which chamber?

• Left atrium
• Right atrium
• Left ventricle
• Right ventricle

Correct Answer: Right atrium

Q7. Which cardiac chamber has the thickest myocardium and generates the highest pressure?

• Right atrium
• Right ventricle
• Left atrium
• Left ventricle

Correct Answer: Left ventricle

Q8. Which vessels carry oxygenated blood from the lungs to the heart?

• Pulmonary arteries
• Pulmonary veins
• Superior and inferior vena cava
• Coronary veins

Correct Answer: Pulmonary veins

Q9. Which circulation is characterized by lower vascular resistance and lower pressures?

• Systemic circulation
• Pulmonary circulation
• Coronary circulation
• Portal circulation

Correct Answer: Pulmonary circulation

Q10. Where is the sinoatrial (SA) node primarily located?

• Interventricular septum near apex
• Upper wall of right atrium near the superior vena cava opening
• Posterior wall of left atrium
• At the junction of bundle branches

Correct Answer: Upper wall of right atrium near the superior vena cava opening

Q11. The atrioventricular (AV) node is located in which area?

• Interatrial septum near the coronary sinus opening
• Left ventricular free wall
• Within the pulmonary valve cusps
• At the sinoatrial node

Correct Answer: Interatrial septum near the coronary sinus opening

Q12. What is the correct sequence of conduction through the heart after the SA node?

• AV node → Purkinje fibers → Bundle of His → Bundle branches
• Bundle of His → AV node → Purkinje fibers → Bundle branches
• AV node → Bundle of His → Left and right bundle branches → Purkinje fibers
• Purkinje fibers → AV node → Bundle branches → Bundle of His

Correct Answer: AV node → Bundle of His → Left and right bundle branches → Purkinje fibers

Q13. The first heart sound (S1) corresponds to the closure of which valves?

• Semilunar valves (aortic and pulmonary)
• Atrioventricular valves (mitral and tricuspid)
• Coronary ostia
• Pulmonary veins ostia

Correct Answer: Atrioventricular valves (mitral and tricuspid)

Q14. Stroke volume (SV) is best defined as:

• End-systolic volume minus end-diastolic volume
• End-diastolic volume minus end-systolic volume
• Heart rate multiplied by cardiac output
• Left ventricular ejection fraction multiplied by heart rate

Correct Answer: End-diastolic volume minus end-systolic volume

Q15. Cardiac output (CO) is calculated by which relationship?

• CO = Stroke volume × Heart rate
• CO = End-diastolic volume − End-systolic volume
• CO = Mean arterial pressure / Heart rate
• CO = Preload × Afterload

Correct Answer: CO = Stroke volume × Heart rate

Q16. Preload is most closely related to which of the following?

• Aortic pressure during systole
• End-diastolic ventricular volume or wall stress before contraction
• Arterial vascular resistance
• Heart rate variability

Correct Answer: End-diastolic ventricular volume or wall stress before contraction

Q17. Afterload is best described as:

• The venous return to the heart during diastole
• The resistance the ventricle must overcome to eject blood (e.g., aortic pressure)
• The maximal contractile force at rest
• The filling time during diastole

Correct Answer: The resistance the ventricle must overcome to eject blood (e.g., aortic pressure)

Q18. The Frank–Starling mechanism explains that increasing preload leads to:

• Decreased stroke volume due to overstretching
• Increased stroke volume due to enhanced sarcomere stretch and force
• No change in cardiac output
• Immediate decrease in contractility

Correct Answer: Increased stroke volume due to enhanced sarcomere stretch and force

Q19. Which change at the cellular level most directly increases cardiac contractility?

• Decreased intracellular calcium in cardiomyocytes
• Increased intracellular calcium in cardiomyocytes
• Reduced sympathetic stimulation of β1 receptors
• Increased afterload without change in preload

Correct Answer: Increased intracellular calcium in cardiomyocytes

Q20. A common clinical approximation for mean arterial pressure (MAP) is which formula?

• MAP ≈ Systolic pressure + Diastolic pressure
• MAP ≈ Diastolic pressure + one-third of pulse pressure (Systolic − Diastolic)
• MAP ≈ Heart rate × Stroke volume
• MAP ≈ End-diastolic volume / End-systolic volume

Correct Answer: MAP ≈ Diastolic pressure + one-third of pulse pressure (Systolic − Diastolic)

Q21. A holosystolic murmur at the apex radiating to the axilla most likely indicates:

• Aortic stenosis
• Pulmonary stenosis
• Mitral regurgitation
• Tricuspid stenosis

Correct Answer: Mitral regurgitation

Q22. In fetal circulation, which structure allows blood to flow directly from the right atrium to the left atrium?

• Ductus arteriosus
• Foramen ovale
• Ligamentum arteriosum
• Coronary sinus

Correct Answer: Foramen ovale

Q23. The ductus arteriosus connects which two vessels in fetal life?

• Left atrium to left ventricle
• Pulmonary trunk to descending aorta
• Superior vena cava to right atrium
• Coronary artery to aorta

Correct Answer: Pulmonary trunk to descending aorta

Q24. Which layer of the heart wall contains the cardiac muscle responsible for contraction?

• Endocardium
• Myocardium
• Epicardium
• Pericardial cavity

Correct Answer: Myocardium

Q25. During ventricular systole, which structure prevents backflow of blood into the left atrium?

• Aortic valve
• Pulmonary valve
• Mitral valve
• Tricuspid valve

Correct Answer: Mitral valve

Q26. Which vessel uniquely carries deoxygenated blood from the heart to the lungs?

• Pulmonary artery
• Pulmonary vein
• Aorta
• Coronary artery

Correct Answer: Pulmonary artery

Q27. Which condition primarily increases left ventricular afterload?

• Systemic hypotension
• Systemic hypertension (increased aortic pressure)
• Decreased blood viscosity
• Increased venous return without rise in arterial pressure

Correct Answer: Systemic hypertension (increased aortic pressure)

Q28. Coronary perfusion of the left ventricle predominantly occurs during which phase of the cardiac cycle?

• Systole
• Diastole
• Atrial contraction only
• Isovolumetric contraction only

Correct Answer: Diastole

Q29. A ventricular gallop (S3) is typically associated with:

• Normal late systolic ejection
• Rapid passive ventricular filling and increased filling pressures
• Closure of semilunar valves
• Electrical conduction delay at the AV node

Correct Answer: Rapid passive ventricular filling and increased filling pressures

Q30. Which pharmacologic action would most directly decrease cardiac output?

• Administration of a β1-adrenergic blocker (negative chronotropic and inotropic effect)
• Administration of a β1-adrenergic agonist (positive inotrope)
• Intravenous saline bolus increasing preload
• Administration of a positive inotropic drug like dobutamine

Correct Answer: Administration of a β1-adrenergic blocker (negative chronotropic and inotropic effect)

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com