WGU D313 ANATOMY AND PHYSIOLOGY II GUIDE CURRENTLY
TESTING EXAM – 300 QUESTIONS DETAILED VERIFIED
ANSWERS WITH RATIONALES (100% CORRECT ANSWERS /
ALREADY GRADED)
SECTION 1: CARDIOVASCULAR HEMODYNAMICS (Questions 1–50)
1. What is the primary pacemaker of the heart?
A) Atrioventricular node
B) Purkinje fibers
C) Sinoatrial node
D) Bundle of His
Correct: C
Rationale: The sinoatrial node generates action potentials at the highest intrinsic
rate
(60-100 bpm) and drives the entire cardiac cycle, making it the primary
pacemaker.
The AV node has a slower rate (40-60 bpm) and serves as a backup.
2. Which valve prevents backflow from the left ventricle into the left atrium?
A) Aortic valve
B) Pulmonary valve
C) Tricuspid valve
D) Mitral valve
Correct: D
Rationale: The mitral (bicuspid) valve is located between the left atrium and left
ventricle.
During ventricular systole, it closes to prevent blood from flowing back into the
atrium.
The aortic valve prevents backflow from the aorta into the left ventricle.
3. What is the correct pathway of blood flow through the heart?
1
,A) Right atrium → Tricuspid valve → Right ventricle → Pulmonary valve →
Pulmonary arteries → Lungs → Pulmonary veins → Left atrium → Mitral valve →
Left ventricle → Aortic valve → Aorta
B) Right atrium → Mitral valve → Right ventricle → Aortic valve → Lungs
C) Left atrium → Tricuspid valve → Left ventricle → Pulmonary valve → Lungs
D) Right ventricle → Pulmonary veins → Left atrium → Aortic valve
Correct: A
Rationale: Blood flows from the systemic circulation into the right atrium, through
the tricuspid valve into the right ventricle, out the pulmonary valve to the lungs
via pulmonary arteries, returns via pulmonary veins to the left atrium, passes
through the mitral valve into the left ventricle, and exits through the aortic valve
to the body.
4. Which layer of the heart wall is responsible for the contractile force?
A) Epicardium
B) Endocardium
C) Myocardium
D) Pericardium
Correct: C
Rationale: The myocardium is the middle, thickest layer composed of cardiac
muscle
cells (cardiomyocytes) that generate the force for contraction. The epicardium is
the
outer layer, endocardium lines the chambers, and pericardium is the protective
sac.
5. What is cardiac output (CO)?
A) The volume of blood pumped by each ventricle per minute
B) The volume of blood pumped by each ventricle per beat
C) The total blood volume in the body
D) The pressure exerted by blood on arterial walls
Correct: A
2
,Rationale: Cardiac output = Heart rate × Stroke volume. It represents the total
volume
of blood ejected by each ventricle in one minute (normal ~4-8 L/min). Stroke
volume
is the volume per beat (Option B).
6. If heart rate is 75 bpm and stroke volume is 70 mL, what is the cardiac output?
A) 5.25 L/min
B) 4.50 L/min
C) 6.00 L/min
D) 7.00 L/min
Correct: A
Rationale: CO = HR × SV = 75 bpm × 0.070 L = 5.25 L/min. This falls within the
normal resting cardiac output range of 4–8 L/min.
7. Which of the following increases stroke volume according to the Frank-Starling
law?
A) Increased heart rate
B) Increased venous return
C) Increased peripheral resistance
D) Decreased contractility
Correct: B
Rationale: The Frank-Starling law states that the heart pumps more blood when
more
blood returns to it (increased preload/venous return). This stretches the
ventricular
myocardium, increasing the force of contraction. Increased HR does not directly
increase SV; it can decrease filling time.
8. What is the primary function of the chordae tendineae?
A) To generate electrical impulses
B) To anchor the AV valve cusps to the papillary muscles
C) To regulate blood flow into the coronary arteries
3
, D) To connect the atria to the ventricles
Correct: B
Rationale: Chordae tendineae are fibrous cords that attach the atrioventricular
valve
cusps (mitral and tricuspid) to the papillary muscles in the ventricles. They
prevent
valve prolapse (eversion) into the atria during ventricular systole.
9. What is the normal resting heart rate set by the SA node?
A) 20–40 bpm
B) 40–60 bpm
C) 60–100 bpm
D) 100–140 bpm
Correct: C
Rationale: The SA node intrinsically fires at 60–100 bpm. The AV node fires at
40–60 bpm (backup), and Purkinje fibers at 20–40 bpm (third backup).
10. Which wave on an ECG represents atrial depolarization?
A) P wave
B) QRS complex
C) T wave
D) U wave
Correct: A
Rationale: The P wave represents atrial depolarization (contraction). The QRS
complex represents ventricular depolarization, and the T wave represents
ventricular
repolarization.
11. What is the significance of the QRS complex on an ECG?
A) Atrial repolarization
B) Ventricular depolarization
C) Ventricular repolarization
D) AV node delay
4
TESTING EXAM – 300 QUESTIONS DETAILED VERIFIED
ANSWERS WITH RATIONALES (100% CORRECT ANSWERS /
ALREADY GRADED)
SECTION 1: CARDIOVASCULAR HEMODYNAMICS (Questions 1–50)
1. What is the primary pacemaker of the heart?
A) Atrioventricular node
B) Purkinje fibers
C) Sinoatrial node
D) Bundle of His
Correct: C
Rationale: The sinoatrial node generates action potentials at the highest intrinsic
rate
(60-100 bpm) and drives the entire cardiac cycle, making it the primary
pacemaker.
The AV node has a slower rate (40-60 bpm) and serves as a backup.
2. Which valve prevents backflow from the left ventricle into the left atrium?
A) Aortic valve
B) Pulmonary valve
C) Tricuspid valve
D) Mitral valve
Correct: D
Rationale: The mitral (bicuspid) valve is located between the left atrium and left
ventricle.
During ventricular systole, it closes to prevent blood from flowing back into the
atrium.
The aortic valve prevents backflow from the aorta into the left ventricle.
3. What is the correct pathway of blood flow through the heart?
1
,A) Right atrium → Tricuspid valve → Right ventricle → Pulmonary valve →
Pulmonary arteries → Lungs → Pulmonary veins → Left atrium → Mitral valve →
Left ventricle → Aortic valve → Aorta
B) Right atrium → Mitral valve → Right ventricle → Aortic valve → Lungs
C) Left atrium → Tricuspid valve → Left ventricle → Pulmonary valve → Lungs
D) Right ventricle → Pulmonary veins → Left atrium → Aortic valve
Correct: A
Rationale: Blood flows from the systemic circulation into the right atrium, through
the tricuspid valve into the right ventricle, out the pulmonary valve to the lungs
via pulmonary arteries, returns via pulmonary veins to the left atrium, passes
through the mitral valve into the left ventricle, and exits through the aortic valve
to the body.
4. Which layer of the heart wall is responsible for the contractile force?
A) Epicardium
B) Endocardium
C) Myocardium
D) Pericardium
Correct: C
Rationale: The myocardium is the middle, thickest layer composed of cardiac
muscle
cells (cardiomyocytes) that generate the force for contraction. The epicardium is
the
outer layer, endocardium lines the chambers, and pericardium is the protective
sac.
5. What is cardiac output (CO)?
A) The volume of blood pumped by each ventricle per minute
B) The volume of blood pumped by each ventricle per beat
C) The total blood volume in the body
D) The pressure exerted by blood on arterial walls
Correct: A
2
,Rationale: Cardiac output = Heart rate × Stroke volume. It represents the total
volume
of blood ejected by each ventricle in one minute (normal ~4-8 L/min). Stroke
volume
is the volume per beat (Option B).
6. If heart rate is 75 bpm and stroke volume is 70 mL, what is the cardiac output?
A) 5.25 L/min
B) 4.50 L/min
C) 6.00 L/min
D) 7.00 L/min
Correct: A
Rationale: CO = HR × SV = 75 bpm × 0.070 L = 5.25 L/min. This falls within the
normal resting cardiac output range of 4–8 L/min.
7. Which of the following increases stroke volume according to the Frank-Starling
law?
A) Increased heart rate
B) Increased venous return
C) Increased peripheral resistance
D) Decreased contractility
Correct: B
Rationale: The Frank-Starling law states that the heart pumps more blood when
more
blood returns to it (increased preload/venous return). This stretches the
ventricular
myocardium, increasing the force of contraction. Increased HR does not directly
increase SV; it can decrease filling time.
8. What is the primary function of the chordae tendineae?
A) To generate electrical impulses
B) To anchor the AV valve cusps to the papillary muscles
C) To regulate blood flow into the coronary arteries
3
, D) To connect the atria to the ventricles
Correct: B
Rationale: Chordae tendineae are fibrous cords that attach the atrioventricular
valve
cusps (mitral and tricuspid) to the papillary muscles in the ventricles. They
prevent
valve prolapse (eversion) into the atria during ventricular systole.
9. What is the normal resting heart rate set by the SA node?
A) 20–40 bpm
B) 40–60 bpm
C) 60–100 bpm
D) 100–140 bpm
Correct: C
Rationale: The SA node intrinsically fires at 60–100 bpm. The AV node fires at
40–60 bpm (backup), and Purkinje fibers at 20–40 bpm (third backup).
10. Which wave on an ECG represents atrial depolarization?
A) P wave
B) QRS complex
C) T wave
D) U wave
Correct: A
Rationale: The P wave represents atrial depolarization (contraction). The QRS
complex represents ventricular depolarization, and the T wave represents
ventricular
repolarization.
11. What is the significance of the QRS complex on an ECG?
A) Atrial repolarization
B) Ventricular depolarization
C) Ventricular repolarization
D) AV node delay
4
