BIOS 255 Anatomy and Physiology III
ACTUAL EXAM 2024/2025 | Exam 2
Comprehensive Review | 150 Questions |
Chamberlain University | Verified
Answers | Pass Guaranteed - A+ Graded
SECTION 1: CARDIOVASCULAR SYSTEM – HEART
ANATOMY AND PHYSIOLOGY
Q1: Heart Valves – Mitral Valve Function
Which structure is responsible for preventing backflow of blood from the left ventricle
into the left atrium during ventricular contraction?
A. Tricuspid valve
B. Pulmonary semilunar valve
C. Mitral valve (bicuspid valve) [CORRECT]
D. Aortic semilunar valve
Correct Answer: C
Rationale:
The mitral (bicuspid) valve is located between the left atrium and left ventricle . During
ventricular systole (contraction), it closes to prevent backflow of oxygenated blood into the
left atrium. The tricuspid valve (A) is on the right side of the heart. The pulmonary (B) and
aortic (D) semilunar valves prevent backflow into the ventricles from the pulmonary trunk and
aorta, respectively.
Chamberlain Note:
● Valvular function:
○ AV valves (tricuspid, mitral): Prevent backflow into atria during ventricular
systole .
○ Semilunar valves (pulmonary, aortic): Prevent backflow into ventricles during
ventricular diastole .
, ● Valvular disorders:
○ Stenosis: Narrowing → ↑afterload.
○ Insufficiency/regurgitation: Leakage → ↓cardiac output.
Q2: ECG Interpretation – First-Degree AV Block
A patient's ECG shows a normal P wave, a prolonged PR interval (>0.20 seconds), and a
normal QRS complex. This rhythm is most consistent with:
A. First-degree atrioventricular (AV) block [CORRECT]
B. Second-degree AV block Mobitz I
C. Third-degree AV block
D. Atrial fibrillation
Correct Answer: A
Rationale:
First-degree AV block is characterized by a prolonged PR interval (>0.20 seconds) with all
P waves conducted to the ventricles, resulting in normal QRS complexes. This indicates
delayed conduction through the AV node . Second-degree Mobitz I (B) shows
progressive PR prolongation with dropped beats. Third-degree block (C) shows
complete AV dissociation (P waves and QRS complexes are independent). Atrial fibrillation
(D) has no identifiable P waves and an irregularly irregular rhythm.
Chamberlain Note:
● ECG interpretation tips:
○ PR interval: 0.12–0.20 seconds (normal).
○ QRS duration: <0.12 seconds (normal).
○ First-degree AV block: PR >0.20 sec, 1:1 conduction.
○ Second-degree Mobitz I: Progressive PR prolongation → dropped beat.
○ Third-degree block: No relationship between P waves and QRS
complexes.
Q3: Cardiac Cycle – Ventricular Systole
During ventricular systole, which of the following events occurs?
A. The atria contract, forcing blood into the ventricles
B. The AV valves close, and the semilunar valves open [CORRECT]
C. Blood flows passively from the atria to the ventricles
D. The heart is in complete relaxation (quiescent period)
,Correct Answer: B
Rationale:
During ventricular systole , the ventricles contract, causing:
● AV valves (tricuspid, mitral) to close (prevents backflow into atria).
● Semilunar valves (pulmonary, aortic) to open (allows ejection into pulmonary
trunk/aorta).
Atrial contraction (A) occurs during atrial systole . Passive blood flow (C) occurs during
ventricular diastole . Complete relaxation (D) describes the quiescent period (brief
pause between systole and diastole).
Chamberlain Note:
● Cardiac cycle phases:
1. Atrial systole : Atria contract → ventricular filling completes.
2. Ventricular systole : Ventricles contract → ejection phase .
3. Diastole : Relaxation and filling (70% of ventricular filling is passive).
Q4: Heart Sounds – S1 and S2
The first heart sound (S1) is primarily associated with the closure of which valves?
A. Aortic and pulmonary semilunar valves
B. Tricuspid and mitral (bicuspid) valves [CORRECT]
C. Aortic and mitral valves
D. Pulmonary and tricuspid valves
Correct Answer: B
Rationale:
S1 ("lub") is caused by the closure of the AV valves (tricuspid and mitral) at the beginning
of ventricular systole . The semilunar valves (A) close during ventricular diastole ,
producing S2 ("dub"). Options C and D incorrectly pair semilunar and AV valves.
Chamberlain Note:
● Heart sounds:
○ S1: AV valve closure (beginning of systole).
○ S2: Semilunar valve closure (end of systole).
○ S3: Early diastole (rapid ventricular filling; may indicate heart failure if heard in
adults).
○ S4: Late diastole (atrial contraction against a stiff ventricle; indicates
hypertension or hypertrophy).
, Q5: Cardiac Conduction – SA Node
Which structure is the primary pacemaker of the heart, initiating the cardiac cycle?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node [CORRECT]
C. Bundle of His
D. Purkinje fibers
Correct Answer: B
Rationale:
The SA node (located in the right atrium near the superior vena cava) is the primary
pacemaker, initiating impulses at 60–100 bpm. The AV node (A) delays impulses to allow atrial
emptying. The Bundle of His (C) and Purkinje fibers (D) distribute impulses to the
ventricles.
Chamberlain Note:
● Conduction pathway:
○ SA node → internodal pathways → AV node → Bundle of His → bundle
branches → Purkinje fibers.
● Intrinsic rates:
○ SA node : 60–100 bpm.
○ AV node : 40–60 bpm.
○ Ventricles: 20–40 bpm.
Q6: Coronary Circulation – Right Coronary Artery
Which vessel primarily supplies blood to the right atrium, right ventricle, and posterior
portion of the left ventricle?
A. Left anterior descending artery
B. Right coronary artery (RCA) [CORRECT]
C. Left circumflex artery
D. Posterior interventricular artery
Correct Answer: B
Rationale:
The right coronary artery (RCA) supplies:
● Right atrium.
● Right ventricle .
● Posterior left ventricle (via posterior descending artery).
● SA node (60% of people).
ACTUAL EXAM 2024/2025 | Exam 2
Comprehensive Review | 150 Questions |
Chamberlain University | Verified
Answers | Pass Guaranteed - A+ Graded
SECTION 1: CARDIOVASCULAR SYSTEM – HEART
ANATOMY AND PHYSIOLOGY
Q1: Heart Valves – Mitral Valve Function
Which structure is responsible for preventing backflow of blood from the left ventricle
into the left atrium during ventricular contraction?
A. Tricuspid valve
B. Pulmonary semilunar valve
C. Mitral valve (bicuspid valve) [CORRECT]
D. Aortic semilunar valve
Correct Answer: C
Rationale:
The mitral (bicuspid) valve is located between the left atrium and left ventricle . During
ventricular systole (contraction), it closes to prevent backflow of oxygenated blood into the
left atrium. The tricuspid valve (A) is on the right side of the heart. The pulmonary (B) and
aortic (D) semilunar valves prevent backflow into the ventricles from the pulmonary trunk and
aorta, respectively.
Chamberlain Note:
● Valvular function:
○ AV valves (tricuspid, mitral): Prevent backflow into atria during ventricular
systole .
○ Semilunar valves (pulmonary, aortic): Prevent backflow into ventricles during
ventricular diastole .
, ● Valvular disorders:
○ Stenosis: Narrowing → ↑afterload.
○ Insufficiency/regurgitation: Leakage → ↓cardiac output.
Q2: ECG Interpretation – First-Degree AV Block
A patient's ECG shows a normal P wave, a prolonged PR interval (>0.20 seconds), and a
normal QRS complex. This rhythm is most consistent with:
A. First-degree atrioventricular (AV) block [CORRECT]
B. Second-degree AV block Mobitz I
C. Third-degree AV block
D. Atrial fibrillation
Correct Answer: A
Rationale:
First-degree AV block is characterized by a prolonged PR interval (>0.20 seconds) with all
P waves conducted to the ventricles, resulting in normal QRS complexes. This indicates
delayed conduction through the AV node . Second-degree Mobitz I (B) shows
progressive PR prolongation with dropped beats. Third-degree block (C) shows
complete AV dissociation (P waves and QRS complexes are independent). Atrial fibrillation
(D) has no identifiable P waves and an irregularly irregular rhythm.
Chamberlain Note:
● ECG interpretation tips:
○ PR interval: 0.12–0.20 seconds (normal).
○ QRS duration: <0.12 seconds (normal).
○ First-degree AV block: PR >0.20 sec, 1:1 conduction.
○ Second-degree Mobitz I: Progressive PR prolongation → dropped beat.
○ Third-degree block: No relationship between P waves and QRS
complexes.
Q3: Cardiac Cycle – Ventricular Systole
During ventricular systole, which of the following events occurs?
A. The atria contract, forcing blood into the ventricles
B. The AV valves close, and the semilunar valves open [CORRECT]
C. Blood flows passively from the atria to the ventricles
D. The heart is in complete relaxation (quiescent period)
,Correct Answer: B
Rationale:
During ventricular systole , the ventricles contract, causing:
● AV valves (tricuspid, mitral) to close (prevents backflow into atria).
● Semilunar valves (pulmonary, aortic) to open (allows ejection into pulmonary
trunk/aorta).
Atrial contraction (A) occurs during atrial systole . Passive blood flow (C) occurs during
ventricular diastole . Complete relaxation (D) describes the quiescent period (brief
pause between systole and diastole).
Chamberlain Note:
● Cardiac cycle phases:
1. Atrial systole : Atria contract → ventricular filling completes.
2. Ventricular systole : Ventricles contract → ejection phase .
3. Diastole : Relaxation and filling (70% of ventricular filling is passive).
Q4: Heart Sounds – S1 and S2
The first heart sound (S1) is primarily associated with the closure of which valves?
A. Aortic and pulmonary semilunar valves
B. Tricuspid and mitral (bicuspid) valves [CORRECT]
C. Aortic and mitral valves
D. Pulmonary and tricuspid valves
Correct Answer: B
Rationale:
S1 ("lub") is caused by the closure of the AV valves (tricuspid and mitral) at the beginning
of ventricular systole . The semilunar valves (A) close during ventricular diastole ,
producing S2 ("dub"). Options C and D incorrectly pair semilunar and AV valves.
Chamberlain Note:
● Heart sounds:
○ S1: AV valve closure (beginning of systole).
○ S2: Semilunar valve closure (end of systole).
○ S3: Early diastole (rapid ventricular filling; may indicate heart failure if heard in
adults).
○ S4: Late diastole (atrial contraction against a stiff ventricle; indicates
hypertension or hypertrophy).
, Q5: Cardiac Conduction – SA Node
Which structure is the primary pacemaker of the heart, initiating the cardiac cycle?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node [CORRECT]
C. Bundle of His
D. Purkinje fibers
Correct Answer: B
Rationale:
The SA node (located in the right atrium near the superior vena cava) is the primary
pacemaker, initiating impulses at 60–100 bpm. The AV node (A) delays impulses to allow atrial
emptying. The Bundle of His (C) and Purkinje fibers (D) distribute impulses to the
ventricles.
Chamberlain Note:
● Conduction pathway:
○ SA node → internodal pathways → AV node → Bundle of His → bundle
branches → Purkinje fibers.
● Intrinsic rates:
○ SA node : 60–100 bpm.
○ AV node : 40–60 bpm.
○ Ventricles: 20–40 bpm.
Q6: Coronary Circulation – Right Coronary Artery
Which vessel primarily supplies blood to the right atrium, right ventricle, and posterior
portion of the left ventricle?
A. Left anterior descending artery
B. Right coronary artery (RCA) [CORRECT]
C. Left circumflex artery
D. Posterior interventricular artery
Correct Answer: B
Rationale:
The right coronary artery (RCA) supplies:
● Right atrium.
● Right ventricle .
● Posterior left ventricle (via posterior descending artery).
● SA node (60% of people).
