1
PNB 2265 Exam 3 Actual Exam 2026/2027 –
Complete Exam-Style Questions with
Detailed Rationales | 100% Verified – Pass
Guaranteed – A+ Graded
Section 1: Cardiovascular System - Heart & Hemodynamics (Questions 1-20)
Q1: Which chamber of the heart receives oxygenated blood from the lungs?
A. Right Atrium
B. Right Ventricle
C. Left Atrium
D. Left Ventricle
Correct Answer: C
C. Left Atrium [CORRECT]
Rationale: The pulmonary veins carry oxygenated blood from the lungs to the left atrium. The
right atrium receives deoxygenated blood from the body.
Q2: During ventricular systole, which valves are open to allow blood ejection?
A. Tricuspid and Mitral valves
B. Aortic and Pulmonary valves
C. Tricuspid and Pulmonary valves
D. Mitral and Aortic valves
Correct Answer: B
B. Aortic and Pulmonary valves [CORRECT]
Rationale: During ventricular systole (contraction), the ventricular pressure rises, forcing the
atrioventricular valves (tricuspid and mitral) closed. The semilunar valves (aortic and
pulmonary) open to allow blood to exit the heart.
,2
Q3: The first heart sound (S1) is caused by the closure of which valves?
A. Aortic and Pulmonary valves
B. Mitral and Tricuspid valves
C. Tricuspid and Aortic valves
D. Mitral and Pulmonary valves
Correct Answer: B
B. Mitral and Tricuspid valves [CORRECT]
Rationale: S1 ("Lub") is produced by the closure of the atrioventricular valves (tricuspid and
mitral) at the beginning of ventricular systole.
Q4: Which component of the conduction system is known as the "pacemaker" of the heart?
A. Atrioventricular (AV) Node
B. Bundle of His
C. Sinoatrial (SA) Node
D. Purkinje Fibers
Correct Answer: C
C. Sinoatrial (SA) Node [CORRECT]
Rationale: The SA node, located in the right atrium near the superior vena cava, spontaneously
depolarizes and initiates the heartbeat, setting the rhythm for the entire heart.
Q5: An increase in end-diastolic volume (EDV) would most likely cause:
A. A decrease in stroke volume.
B. An increase in stroke volume.
C. No change in cardiac output.
D. A decrease in heart rate.
Correct Answer: B
B. An increase in stroke volume. [CORRECT]
, 3
Rationale: According to the Frank-Starling law, an increase in EDV (preload) stretches the
myocardial fibers, leading to a more forceful contraction and an increased stroke volume.
Q6: Which coronary artery supplies blood to the left atrium and left ventricle?
A. Right Coronary Artery (RCA)
B. Left Coronary Artery (LCA)
C. Circumflex Artery (branch of LCA)
D. Anterior Interventricular Artery (LAD)
Correct Answer: B
B. Left Coronary Artery (LCA) [CORRECT]
Rationale: The Left Coronary Artery (LCA) supplies the left atrium and most of the left
ventricle. It branches into the Circumflex artery and the Left Anterior Descending (LAD) artery.
Q7: The ECG waveform representing atrial depolarization is the:
A. P wave
B. QRS complex
C. T wave
D. PR interval
Correct Answer: A
A. P wave [CORRECT]
Rationale: The P wave represents the depolarization of the atria, which initiates atrial
contraction. The QRS complex represents ventricular depolarization.
Q8: If the AV node is damaged and fails to delay the impulse, what is the most likely cardiac
consequence?
A. Atrial fibrillation
B. Ventricular fibrillation
C. Inability of ventricles to fill completely (reduced stroke volume)
PNB 2265 Exam 3 Actual Exam 2026/2027 –
Complete Exam-Style Questions with
Detailed Rationales | 100% Verified – Pass
Guaranteed – A+ Graded
Section 1: Cardiovascular System - Heart & Hemodynamics (Questions 1-20)
Q1: Which chamber of the heart receives oxygenated blood from the lungs?
A. Right Atrium
B. Right Ventricle
C. Left Atrium
D. Left Ventricle
Correct Answer: C
C. Left Atrium [CORRECT]
Rationale: The pulmonary veins carry oxygenated blood from the lungs to the left atrium. The
right atrium receives deoxygenated blood from the body.
Q2: During ventricular systole, which valves are open to allow blood ejection?
A. Tricuspid and Mitral valves
B. Aortic and Pulmonary valves
C. Tricuspid and Pulmonary valves
D. Mitral and Aortic valves
Correct Answer: B
B. Aortic and Pulmonary valves [CORRECT]
Rationale: During ventricular systole (contraction), the ventricular pressure rises, forcing the
atrioventricular valves (tricuspid and mitral) closed. The semilunar valves (aortic and
pulmonary) open to allow blood to exit the heart.
,2
Q3: The first heart sound (S1) is caused by the closure of which valves?
A. Aortic and Pulmonary valves
B. Mitral and Tricuspid valves
C. Tricuspid and Aortic valves
D. Mitral and Pulmonary valves
Correct Answer: B
B. Mitral and Tricuspid valves [CORRECT]
Rationale: S1 ("Lub") is produced by the closure of the atrioventricular valves (tricuspid and
mitral) at the beginning of ventricular systole.
Q4: Which component of the conduction system is known as the "pacemaker" of the heart?
A. Atrioventricular (AV) Node
B. Bundle of His
C. Sinoatrial (SA) Node
D. Purkinje Fibers
Correct Answer: C
C. Sinoatrial (SA) Node [CORRECT]
Rationale: The SA node, located in the right atrium near the superior vena cava, spontaneously
depolarizes and initiates the heartbeat, setting the rhythm for the entire heart.
Q5: An increase in end-diastolic volume (EDV) would most likely cause:
A. A decrease in stroke volume.
B. An increase in stroke volume.
C. No change in cardiac output.
D. A decrease in heart rate.
Correct Answer: B
B. An increase in stroke volume. [CORRECT]
, 3
Rationale: According to the Frank-Starling law, an increase in EDV (preload) stretches the
myocardial fibers, leading to a more forceful contraction and an increased stroke volume.
Q6: Which coronary artery supplies blood to the left atrium and left ventricle?
A. Right Coronary Artery (RCA)
B. Left Coronary Artery (LCA)
C. Circumflex Artery (branch of LCA)
D. Anterior Interventricular Artery (LAD)
Correct Answer: B
B. Left Coronary Artery (LCA) [CORRECT]
Rationale: The Left Coronary Artery (LCA) supplies the left atrium and most of the left
ventricle. It branches into the Circumflex artery and the Left Anterior Descending (LAD) artery.
Q7: The ECG waveform representing atrial depolarization is the:
A. P wave
B. QRS complex
C. T wave
D. PR interval
Correct Answer: A
A. P wave [CORRECT]
Rationale: The P wave represents the depolarization of the atria, which initiates atrial
contraction. The QRS complex represents ventricular depolarization.
Q8: If the AV node is damaged and fails to delay the impulse, what is the most likely cardiac
consequence?
A. Atrial fibrillation
B. Ventricular fibrillation
C. Inability of ventricles to fill completely (reduced stroke volume)
