ECG Cardiac Anatomy 2 — Questions and Answers
Question 1: Which valve separates the left atrium from the left ventricle?
- Tricuspid valve
- Pulmonic valve
- Mitral valve (Correct answer)
- Aortic valve
Correct answer: Mitral valve
The mitral (bicuspid) valve controls blood flow from the left atrium into the left ventricle.
Question 2: The coronary sinus drains deoxygenated blood from the myocardium into which chamber?
- Right ventricle
- Left atrium
- Right atrium (Correct answer)
- Left ventricle
Correct answer: Right atrium
The coronary sinus empties venous blood from the heart muscle directly into the right atrium.
Question 3: Which layer of the heart wall contains the cardiac muscle responsible for contraction?
- Pericardium
- Epicardium
- Endocardium
- Myocardium (Correct answer)
Correct answer: Myocardium
The myocardium is the thick muscular middle layer that generates the contractile force of the heart.
Question 4: The right coronary artery most commonly supplies which structure critical for AV conduction?
- Bundle of His
- Right bundle branch
- AV node (Correct answer)
- SA node
Correct answer: AV node
In about 85–90% of people, the RCA supplies the AV node via the AV nodal artery.
Question 5: Which anatomical landmark divides the right and left sides of the heart externally on the anterior surface?
- Crista terminalis
- Anterior interventricular groove (Correct answer)
- Coronary sulcus
- Posterior interventricular groove
Correct answer: Anterior interventricular groove
The anterior interventricular groove (sulcus) overlies the interventricular septum and contains the LAD artery.
Question 6: Papillary muscles attach to the valve leaflets via which structures?
- Tendinous cords (chordae tendineae) (Correct answer)
- Pectinate muscles
- Trabeculae carneae
- Moderator band
Correct answer: Tendinous cords (chordae tendineae)
Chordae tendineae connect papillary muscles to the AV valve leaflets, preventing eversion during systole.
Question 7: Which cardiac chamber has the thickest wall and why?
- Right atrium — receives all systemic venous return
- Right ventricle — pumps against pulmonary resistance
- Left atrium — receives high-pressure pulmonary veins
- Left ventricle — pumps against systemic vascular resistance (Correct answer)
Correct answer: Left ventricle — pumps against systemic vascular resistance
The left ventricle has the thickest wall (8–12 mm) because it must generate enough pressure to overcome systemic vascular resistance.
ECG Cardiac Anatomy 2
Which valve separates the left atrium from the left ventricle?