STRAIGHTERLINE A&P QUIZ 2 2026/2027 | Complete
Solutions with Verified Answers | Cardiovascular,
Lymphatic/Immune, Respiratory | Pass Guaranteed - A+
Graded
Domain 1: Cardiovascular System — 20 Questions
Q1: A 67-year-old patient presents with chest pain and an ECG shows a prolonged PR
interval (>0.20 seconds) with a consistent 1:1 relationship between P waves and QRS
complexes. The heart rate is 72 bpm. Which conduction abnormality is present?
A. Second-degree AV block Mobitz Type II
B. Third-degree AV block
C. First-degree AV block [CORRECT]
D. Bundle branch block
Correct Answer: C
Rationale: First-degree AV block is characterized by a prolonged PR interval (>0.20
seconds or >5 small squares on ECG) with maintained 1:1 conduction between atria and
ventricles . The PR interval represents the time from atrial depolarization (P wave)
through the AV node, bundle of His, and bundle branches to ventricular depolarization.
Option A is incorrect because Mobitz Type II shows constant PR intervals with
intermittently dropped QRS complexes. Option B is incorrect because third-degree block
shows complete AV dissociation with no relationship between P waves and QRS
complexes. Option D is incorrect because bundle branch block manifests as widened
,QRS complexes (>0.12 seconds) without PR prolongation. This patient has delayed
conduction through the AV node but all impulses eventually reach the ventricles.
Q2: During a cardiac cycle, which event occurs immediately after the P wave on an ECG?
A. Closure of the aortic valve
B. Opening of the mitral valve
C. Atrial contraction and ventricular filling [CORRECT]
D. Isovolumetric contraction
Correct Answer: C
Rationale: The P wave represents atrial depolarization, which triggers atrial contraction
(systole) . This atrial "kick" contributes the final 20-30% of ventricular filling during late
diastole. Option A is incorrect because aortic valve closure occurs after ventricular
repolarization (T wave) during isovolumetric relaxation. Option B is incorrect because
the mitral valve opens during early diastole when ventricular pressure drops below atrial
pressure, before atrial depolarization. Option D is incorrect because isovolumetric
contraction begins after the QRS complex (ventricular depolarization) when all valves
are closed. Understanding the temporal relationship between ECG waves and
mechanical events is essential for cardiac physiology.
Q3: A patient has a heart rate of 75 bpm and a stroke volume of 70 mL. What is their
cardiac output?
A. 4.5 L/min
B. 5.25 L/min [CORRECT]
,C. 6.0 L/min
D. 3.75 L/min
Correct Answer: B
Rationale: Cardiac output (CO) is calculated using the formula: CO = Heart Rate × Stroke
Volume . Calculation: 75 beats/min × 70 mL/beat = 5,250 mL/min = 5.25 L/min. This
falls within the normal range of 4-8 L/min for a resting adult. Option A would result from
64 bpm × 70 mL or 75 bpm × 60 mL. Option C would require approximately 86 bpm or
80 mL stroke volume. Option D represents a low cardiac output state. Cardiac output
regulation is a fundamental concept in cardiovascular physiology, affected by heart rate,
preload, contractility, and afterload.
Q4: Which factor would INCREASE stroke volume through enhanced preload?
A. Decreased venous return
B. Increased venous return [CORRECT]
C. Increased arterial blood pressure
D. Decreased blood volume
Correct Answer: B
Rationale: Preload is the degree of stretch on the ventricular muscle at the end of
diastole, determined primarily by venous return and ventricular filling . Increased venous
return increases end-diastolic volume (EDV), stretching cardiac muscle fibers and
increasing contractile force via the Frank-Starling mechanism. Option A is incorrect
because decreased venous return reduces preload and stroke volume. Option C is
incorrect because increased arterial pressure represents increased afterload, which
, decreases stroke volume. Option D is incorrect because decreased blood volume
reduces venous return and preload. Understanding preload, contractility, and afterload is
essential for analyzing cardiac performance.
Q5: A patient presents with a blood pressure of 165/98 mmHg. Which classification
describes this reading?
A. Normal blood pressure
B. Stage 1 hypertension
C. Stage 2 hypertension [CORRECT]
D. Hypertensive crisis
Correct Answer: C
Rationale: According to ACC/AHA guidelines, Stage 2 hypertension is defined as
systolic pressure ≥140 mmHg or diastolic pressure ≥90 mmHg . This patient's readings
(165/98) exceed both thresholds. Option A is incorrect because normal BP is <120/80
mmHg. Option B (Stage 1) is 130-139 systolic or 80-89 diastolic. Option D requires
readings >180/120 mmHg with signs of end-organ damage. Hypertension is a major
cardiovascular risk factor that increases afterload, leading to left ventricular
hypertrophy and eventual heart failure if untreated.
Q6: Which heart sound is associated with the closure of the semilunar valves (aortic
and pulmonary) at the beginning of diastole?
A. S1 (lub)
B. S2 (dub) [CORRECT]
Solutions with Verified Answers | Cardiovascular,
Lymphatic/Immune, Respiratory | Pass Guaranteed - A+
Graded
Domain 1: Cardiovascular System — 20 Questions
Q1: A 67-year-old patient presents with chest pain and an ECG shows a prolonged PR
interval (>0.20 seconds) with a consistent 1:1 relationship between P waves and QRS
complexes. The heart rate is 72 bpm. Which conduction abnormality is present?
A. Second-degree AV block Mobitz Type II
B. Third-degree AV block
C. First-degree AV block [CORRECT]
D. Bundle branch block
Correct Answer: C
Rationale: First-degree AV block is characterized by a prolonged PR interval (>0.20
seconds or >5 small squares on ECG) with maintained 1:1 conduction between atria and
ventricles . The PR interval represents the time from atrial depolarization (P wave)
through the AV node, bundle of His, and bundle branches to ventricular depolarization.
Option A is incorrect because Mobitz Type II shows constant PR intervals with
intermittently dropped QRS complexes. Option B is incorrect because third-degree block
shows complete AV dissociation with no relationship between P waves and QRS
complexes. Option D is incorrect because bundle branch block manifests as widened
,QRS complexes (>0.12 seconds) without PR prolongation. This patient has delayed
conduction through the AV node but all impulses eventually reach the ventricles.
Q2: During a cardiac cycle, which event occurs immediately after the P wave on an ECG?
A. Closure of the aortic valve
B. Opening of the mitral valve
C. Atrial contraction and ventricular filling [CORRECT]
D. Isovolumetric contraction
Correct Answer: C
Rationale: The P wave represents atrial depolarization, which triggers atrial contraction
(systole) . This atrial "kick" contributes the final 20-30% of ventricular filling during late
diastole. Option A is incorrect because aortic valve closure occurs after ventricular
repolarization (T wave) during isovolumetric relaxation. Option B is incorrect because
the mitral valve opens during early diastole when ventricular pressure drops below atrial
pressure, before atrial depolarization. Option D is incorrect because isovolumetric
contraction begins after the QRS complex (ventricular depolarization) when all valves
are closed. Understanding the temporal relationship between ECG waves and
mechanical events is essential for cardiac physiology.
Q3: A patient has a heart rate of 75 bpm and a stroke volume of 70 mL. What is their
cardiac output?
A. 4.5 L/min
B. 5.25 L/min [CORRECT]
,C. 6.0 L/min
D. 3.75 L/min
Correct Answer: B
Rationale: Cardiac output (CO) is calculated using the formula: CO = Heart Rate × Stroke
Volume . Calculation: 75 beats/min × 70 mL/beat = 5,250 mL/min = 5.25 L/min. This
falls within the normal range of 4-8 L/min for a resting adult. Option A would result from
64 bpm × 70 mL or 75 bpm × 60 mL. Option C would require approximately 86 bpm or
80 mL stroke volume. Option D represents a low cardiac output state. Cardiac output
regulation is a fundamental concept in cardiovascular physiology, affected by heart rate,
preload, contractility, and afterload.
Q4: Which factor would INCREASE stroke volume through enhanced preload?
A. Decreased venous return
B. Increased venous return [CORRECT]
C. Increased arterial blood pressure
D. Decreased blood volume
Correct Answer: B
Rationale: Preload is the degree of stretch on the ventricular muscle at the end of
diastole, determined primarily by venous return and ventricular filling . Increased venous
return increases end-diastolic volume (EDV), stretching cardiac muscle fibers and
increasing contractile force via the Frank-Starling mechanism. Option A is incorrect
because decreased venous return reduces preload and stroke volume. Option C is
incorrect because increased arterial pressure represents increased afterload, which
, decreases stroke volume. Option D is incorrect because decreased blood volume
reduces venous return and preload. Understanding preload, contractility, and afterload is
essential for analyzing cardiac performance.
Q5: A patient presents with a blood pressure of 165/98 mmHg. Which classification
describes this reading?
A. Normal blood pressure
B. Stage 1 hypertension
C. Stage 2 hypertension [CORRECT]
D. Hypertensive crisis
Correct Answer: C
Rationale: According to ACC/AHA guidelines, Stage 2 hypertension is defined as
systolic pressure ≥140 mmHg or diastolic pressure ≥90 mmHg . This patient's readings
(165/98) exceed both thresholds. Option A is incorrect because normal BP is <120/80
mmHg. Option B (Stage 1) is 130-139 systolic or 80-89 diastolic. Option D requires
readings >180/120 mmHg with signs of end-organ damage. Hypertension is a major
cardiovascular risk factor that increases afterload, leading to left ventricular
hypertrophy and eventual heart failure if untreated.
Q6: Which heart sound is associated with the closure of the semilunar valves (aortic
and pulmonary) at the beginning of diastole?
A. S1 (lub)
B. S2 (dub) [CORRECT]
