BIOS 255 Anatomy and Physiology III - Week 1 Comprehensive Quiz
2026 Chamberlain
1. Which layer of the heart wall is composed of cardiac muscle tissue?
A. Epicardium
B. Myocardium
C. Endocardium
D. Pericardium
Answer: B
Rationale: The myocardium is the thick middle layer of the heart composed of cardiac
muscle, responsible for the pumping action.
2. The right side of the heart acts as a pump for which circuit?
A. Systemic circuit
B. Pulmonary circuit
C. Coronary circuit
D. Hepatic circuit
Answer: B
Rationale: The right side of the heart pumps deoxygenated blood to the lungs via the
pulmonary circuit.
3. Which valve prevents the backflow of blood from the left ventricle into the
left atrium?
A. Tricuspid valve
B. Pulmonary valve
C. Aortic valve
D. Bicuspid (Mitral) valve
Answer: D
,Rationale: The bicuspid or mitral valve is located between the left atrium and left
ventricle.
4. What is the primary function of the chordae tendineae?
A. To prevent the AV valves from everting into the atria
B. To conduct electrical impulses
C. To open the semilunar valves
D. To contract the ventricles
Answer: A
Rationale: The chordae tendineae anchor the AV valve flaps to the papillary muscles to
prevent them from blowing back into the atria during ventricular contraction.
5. Which vessel carries oxygenated blood back to the heart from the lungs?
A. Pulmonary artery
B. Superior vena cava
C. Aorta
D. Pulmonary vein
Answer: D
Rationale: The pulmonary veins carry oxygen-rich blood from the lungs into the left
atrium.
6. The ‘pacemaker’ of the heart is known as the:
A. Atrioventricular (AV) node
B. Bundle of His
C. Sinoatrial (SA) node
D. Purkinje fibers
Answer: C
Rationale: The SA node initiates the electrical impulse that sets the heart’s rhythm.
, 7. On an ECG, the P wave represents:
A. Atrial repolarization
B. Ventricular depolarization
C. Atrial depolarization
D. Ventricular repolarization
Answer: C
Rationale: The P wave is the first deflection on an ECG, representing the spread of
electricity through the atria.
8. What causes the first heart sound (S1), often described as ‘lub’?
A. Closing of the semilunar valves
B. Opening of the AV valves
C. Closing of the atrioventricular (AV) valves
D. Contraction of the atria
Answer: C
Rationale: S1 is caused by the closure of the tricuspid and mitral valves at the start of
ventricular systole.
9. The QRS complex on an ECG corresponds to:
A. Atrial contraction
B. Ventricular repolarization
C. Ventricular depolarization
D. Aortic pressure peak
Answer: C
Rationale: The QRS complex represents the electrical activation (depolarization) of the
ventricles.
2026 Chamberlain
1. Which layer of the heart wall is composed of cardiac muscle tissue?
A. Epicardium
B. Myocardium
C. Endocardium
D. Pericardium
Answer: B
Rationale: The myocardium is the thick middle layer of the heart composed of cardiac
muscle, responsible for the pumping action.
2. The right side of the heart acts as a pump for which circuit?
A. Systemic circuit
B. Pulmonary circuit
C. Coronary circuit
D. Hepatic circuit
Answer: B
Rationale: The right side of the heart pumps deoxygenated blood to the lungs via the
pulmonary circuit.
3. Which valve prevents the backflow of blood from the left ventricle into the
left atrium?
A. Tricuspid valve
B. Pulmonary valve
C. Aortic valve
D. Bicuspid (Mitral) valve
Answer: D
,Rationale: The bicuspid or mitral valve is located between the left atrium and left
ventricle.
4. What is the primary function of the chordae tendineae?
A. To prevent the AV valves from everting into the atria
B. To conduct electrical impulses
C. To open the semilunar valves
D. To contract the ventricles
Answer: A
Rationale: The chordae tendineae anchor the AV valve flaps to the papillary muscles to
prevent them from blowing back into the atria during ventricular contraction.
5. Which vessel carries oxygenated blood back to the heart from the lungs?
A. Pulmonary artery
B. Superior vena cava
C. Aorta
D. Pulmonary vein
Answer: D
Rationale: The pulmonary veins carry oxygen-rich blood from the lungs into the left
atrium.
6. The ‘pacemaker’ of the heart is known as the:
A. Atrioventricular (AV) node
B. Bundle of His
C. Sinoatrial (SA) node
D. Purkinje fibers
Answer: C
Rationale: The SA node initiates the electrical impulse that sets the heart’s rhythm.
, 7. On an ECG, the P wave represents:
A. Atrial repolarization
B. Ventricular depolarization
C. Atrial depolarization
D. Ventricular repolarization
Answer: C
Rationale: The P wave is the first deflection on an ECG, representing the spread of
electricity through the atria.
8. What causes the first heart sound (S1), often described as ‘lub’?
A. Closing of the semilunar valves
B. Opening of the AV valves
C. Closing of the atrioventricular (AV) valves
D. Contraction of the atria
Answer: C
Rationale: S1 is caused by the closure of the tricuspid and mitral valves at the start of
ventricular systole.
9. The QRS complex on an ECG corresponds to:
A. Atrial contraction
B. Ventricular repolarization
C. Ventricular depolarization
D. Aortic pressure peak
Answer: C
Rationale: The QRS complex represents the electrical activation (depolarization) of the
ventricles.
