CCT Cardiac Anatomy & Physiology 4 — Questions and Answers
Question 1: Which of the following vessels returns oxygenated blood from the lungs to the left atrium?
- Superior vena cava
- Inferior vena cava
- Pulmonary veins (Correct answer)
- Coronary sinus
Correct answer: Pulmonary veins
The four pulmonary veins return oxygenated blood from the lungs to the left atrium, completing the pulmonary circulation.
Question 2: The Bundle of His divides into left and right bundle branches at which anatomical location?
- AV node
- Top of the interventricular septum (Correct answer)
- Apex of the heart
- Base of the papillary muscles
Correct answer: Top of the interventricular septum
After passing through the AV node, the Bundle of His descends through the fibrous skeleton and divides into left and right bundle branches at the superior interventricular septum.
Question 3: Which coronary artery is most commonly referred to as the 'widow maker' due to the large territory it supplies?
- Right coronary artery
- Left circumflex artery
- Left anterior descending artery (Correct answer)
- Obtuse marginal artery
Correct answer: Left anterior descending artery
The left anterior descending (LAD) artery supplies the anterior wall and a large portion of the interventricular septum; its occlusion causes massive anterior MI with high mortality.
Question 4: What is the approximate normal ejection fraction of the left ventricle?
- 25–35%
- 40–55%
- 55–70% (Correct answer)
- 75–90%
Correct answer: 55–70%
Normal left ventricular ejection fraction (LVEF) is 55–70%, representing the percentage of end-diastolic volume ejected with each beat.
Question 5: The tricuspid valve has how many leaflets?
- Two
- Three (Correct answer)
- Four
- Five
Correct answer: Three
The tricuspid (right AV) valve has three leaflets — anterior, posterior, and septal — which close during systole to prevent backflow into the right atrium.
Question 6: Which phase of the cardiac cycle is associated with the S2 heart sound?
- Closure of the AV valves at the start of systole
- Opening of the semilunar valves
- Closure of the semilunar valves at the end of systole (Correct answer)
- Rapid ventricular filling
Correct answer: Closure of the semilunar valves at the end of systole
S2 is produced by the closure of the aortic and pulmonic semilunar valves at the end of systole, marking the beginning of ventricular diastole.
Question 7: Venous blood from the majority of the myocardium drains into which structure?
- Thebesian veins
- Anterior cardiac veins
- Coronary sinus (Correct answer)
- Superior vena cava
Correct answer: Coronary sinus
The great, middle, and small cardiac veins converge into the coronary sinus, which runs in the posterior AV groove and empties into the right atrium.
CCT Cardiac Anatomy & Physiology 4
Which of the following vessels returns oxygenated blood from the lungs to the left atrium?