ECG Cardiac Anatomy 1 — Questions and Answers
Question 1: Which chamber of the heart has the thickest muscular wall?
- Left ventricle (Correct answer)
- Right ventricle
- Left atrium
- Right atrium
Correct answer: Left ventricle
The left ventricle has the thickest wall because it must generate enough pressure to pump blood throughout the entire systemic circulation.
Question 2: What is the normal pacemaker of the heart?
- Sinoatrial (SA) node (Correct answer)
- Atrioventricular (AV) node
- Bundle of His
- Purkinje fibers
Correct answer: Sinoatrial (SA) node
The SA node, located in the right atrium, generates electrical impulses at 60-100 beats per minute and is the heart's natural pacemaker.
Question 3: Which valve separates the left atrium from the left ventricle?
- Mitral valve (Correct answer)
- Tricuspid valve
- Aortic valve
- Pulmonary valve
Correct answer: Mitral valve
The mitral (bicuspid) valve has two leaflets and prevents backflow from the left ventricle into the left atrium during systole.
Question 4: What is the function of the coronary sinus?
- Collects deoxygenated blood from cardiac veins (Correct answer)
- Delivers oxygenated blood to the myocardium
- Regulates heart rate
- Produces cardiac enzymes
Correct answer: Collects deoxygenated blood from cardiac veins
The coronary sinus is a large vein that collects deoxygenated blood from the cardiac veins and empties it into the right atrium.
Question 5: Which structure delays electrical impulses between the atria and ventricles?
- AV node (Correct answer)
- SA node
- Bundle branches
- Purkinje fibers
Correct answer: AV node
The AV node provides a critical delay of about 0.1 seconds, allowing the atria to finish contracting before the ventricles begin.
Question 6: Which layer of the heart wall contains contractile muscle tissue?
- Myocardium (Correct answer)
- Endocardium
- Epicardium
- Pericardium
Correct answer: Myocardium
The myocardium is the thick middle layer composed of cardiac muscle cells responsible for heart contraction.
ECG Cardiac Anatomy 1
Which chamber of the heart has the thickest muscular wall?