SFSU BIO 230 Human Physiology —
Examination 2 ACTUAL EXAM
2026/2027 | Human Physiology Core
Concepts | Verified Q&A | Pass
Guaranteed - A+ Graded
Section 1: Cardiovascular Physiology (Questions 1–17)
Q1: A patient's stroke volume decreases from 70 mL to 50 mL while heart rate remains unchanged at 80
bpm. What is the new cardiac output?
A. 2.5 L/min
B. 3.0 L/min
C. 4.0 L/min [CORRECT]
D. 5.6 L/min
Correct Answer: C
Rationale: Cardiac output = heart rate × stroke volume. 80 bpm × 0.050 L = 4.0 L/min. The decrease
from the original 5.6 L/min reflects reduced pumping capacity.
Q2: Which ion is primarily responsible for the rapid depolarization phase (Phase 0) of a ventricular
cardiomyocyte action potential?
A. Calcium influx through L-type channels
B. Sodium influx through fast channels [CORRECT]
C. Potassium efflux through delayed rectifier channels
D. Chloride influx through ligand-gated channels
Correct Answer: B
Rationale: Phase 0 is mediated by rapid sodium influx through voltage-gated fast sodium channels.
Calcium influx dominates Phase 2 (plateau), not Phase 0.
, Q3: On a standard ECG, the QRS complex represents which electrical event?
A. Atrial depolarization
B. Atrial repolarization
C. Ventricular depolarization [CORRECT]
D. Ventricular repolarization
Correct Answer: C
Rationale: The QRS complex corresponds to ventricular depolarization. Atrial depolarization produces
the P wave, while ventricular repolarization produces the T wave.
Q4: During which phase of the cardiac cycle does the mitral valve open?
A. Isovolumetric contraction
B. Isovolumetric relaxation
C. Rapid ventricular filling [CORRECT]
D. Atrial contraction
Correct Answer: C
Rationale: The mitral valve opens when left ventricular pressure drops below left atrial pressure during
rapid ventricular filling, immediately following isovolumetric relaxation.
Q5: The first heart sound (S1) is produced by closure of which valves?
A. Aortic and pulmonic valves
B. Mitral and tricuspid valves [CORRECT]
C. Aortic and mitral valves
D. Pulmonic and tricuspid valves
Correct Answer: B
Rationale: S1 results from closure of the atrioventricular valves (mitral and tricuspid) at the onset of
ventricular systole. S2 results from semilunar valve closure.
Q6: According to the Frank-Starling mechanism, increased venous return leads to increased stroke
volume primarily through which mechanism?
A. Increased heart rate via sympathetic stimulation
B. Increased myocardial stretch enhancing contractility [CORRECT]
C. Decreased afterload on the ventricle
D. Increased calcium release from the sarcoplasmic reticulum
Examination 2 ACTUAL EXAM
2026/2027 | Human Physiology Core
Concepts | Verified Q&A | Pass
Guaranteed - A+ Graded
Section 1: Cardiovascular Physiology (Questions 1–17)
Q1: A patient's stroke volume decreases from 70 mL to 50 mL while heart rate remains unchanged at 80
bpm. What is the new cardiac output?
A. 2.5 L/min
B. 3.0 L/min
C. 4.0 L/min [CORRECT]
D. 5.6 L/min
Correct Answer: C
Rationale: Cardiac output = heart rate × stroke volume. 80 bpm × 0.050 L = 4.0 L/min. The decrease
from the original 5.6 L/min reflects reduced pumping capacity.
Q2: Which ion is primarily responsible for the rapid depolarization phase (Phase 0) of a ventricular
cardiomyocyte action potential?
A. Calcium influx through L-type channels
B. Sodium influx through fast channels [CORRECT]
C. Potassium efflux through delayed rectifier channels
D. Chloride influx through ligand-gated channels
Correct Answer: B
Rationale: Phase 0 is mediated by rapid sodium influx through voltage-gated fast sodium channels.
Calcium influx dominates Phase 2 (plateau), not Phase 0.
, Q3: On a standard ECG, the QRS complex represents which electrical event?
A. Atrial depolarization
B. Atrial repolarization
C. Ventricular depolarization [CORRECT]
D. Ventricular repolarization
Correct Answer: C
Rationale: The QRS complex corresponds to ventricular depolarization. Atrial depolarization produces
the P wave, while ventricular repolarization produces the T wave.
Q4: During which phase of the cardiac cycle does the mitral valve open?
A. Isovolumetric contraction
B. Isovolumetric relaxation
C. Rapid ventricular filling [CORRECT]
D. Atrial contraction
Correct Answer: C
Rationale: The mitral valve opens when left ventricular pressure drops below left atrial pressure during
rapid ventricular filling, immediately following isovolumetric relaxation.
Q5: The first heart sound (S1) is produced by closure of which valves?
A. Aortic and pulmonic valves
B. Mitral and tricuspid valves [CORRECT]
C. Aortic and mitral valves
D. Pulmonic and tricuspid valves
Correct Answer: B
Rationale: S1 results from closure of the atrioventricular valves (mitral and tricuspid) at the onset of
ventricular systole. S2 results from semilunar valve closure.
Q6: According to the Frank-Starling mechanism, increased venous return leads to increased stroke
volume primarily through which mechanism?
A. Increased heart rate via sympathetic stimulation
B. Increased myocardial stretch enhancing contractility [CORRECT]
C. Decreased afterload on the ventricle
D. Increased calcium release from the sarcoplasmic reticulum
