Advanced Medical Physiology Comprehensive
Exam 2026 | Cardiovascular, Renal,
Respiratory, Endocrine, Neurophysiology & GI
Systems | Practice Questions
Question 1
A healthy adult suddenly stands from a supine position. Within
seconds, arterial blood pressure briefly decreases before
compensatory mechanisms restore it. Which response most
directly mediates the immediate correction?
A. Increased parasympathetic activity to the sinoatrial node
B. Decreased sympathetic activity to systemic arterioles
C. Increased sympathetic activity causing arteriolar
vasoconstriction and increased heart rate
D. Increased secretion of atrial natriuretic peptide
Correct Answer: C. Increased sympathetic activity causing
arteriolar vasoconstriction and increased heart rate
Rationale: Standing causes venous pooling and transiently
decreases venous return, stroke volume, and arterial pressure.
Reduced stretch of carotid sinus and aortic arch baroreceptors
decreases baroreceptor firing, increasing sympathetic and
,decreasing parasympathetic activity. This rapidly increases
heart rate, contractility, and systemic vascular resistance.
Question 2
A patient has a mutation that prevents voltage-gated sodium
channels in skeletal muscle from rapidly inactivating. Which
effect is most likely?
A. Prolonged depolarization and impaired repolarization
B. Complete absence of action potentials
C. Increased resting membrane potential negativity
D. Increased potassium influx during depolarization
Correct Answer: A. Prolonged depolarization and impaired
repolarization
Rationale: Voltage-gated sodium channels normally open
rapidly during depolarization and then inactivate. Failure of
inactivation causes persistent sodium influx, prolonging
depolarization and interfering with normal repolarization and
subsequent action potential generation.
Question 3
,A researcher increases the extracellular concentration of
potassium surrounding a neuron while keeping all other
variables constant. What is the most immediate effect?
A. Hyperpolarization
B. Depolarization
C. Increased chloride influx
D. No change in membrane potential
Correct Answer: B. Depolarization
Rationale: Increasing extracellular potassium reduces the
concentration gradient driving potassium out of the cell. The
equilibrium potential for potassium becomes less negative,
causing the resting membrane potential to become less
negative and therefore depolarized.
Question 4
A patient has severe hypocalcemia. Which change in neuronal
excitability is most likely?
A. Increased threshold for action potential generation
B. Decreased neuronal excitability
C. Increased neuronal excitability due to reduced threshold
potential
D. Complete inhibition of voltage-gated sodium channels
, Correct Answer: C. Increased neuronal excitability due to
reduced threshold potential
Rationale: Extracellular calcium stabilizes voltage-gated sodium
channels. Low extracellular calcium makes these channels
easier to activate, lowering the threshold for action potential
generation and increasing neuromuscular excitability.
Question 5
A skeletal muscle fiber is experimentally stimulated while
intracellular calcium stores are depleted. Which process is most
directly impaired?
A. ATP production by oxidative phosphorylation
B. Binding of calcium to troponin C
C. Release of acetylcholine from the motor neuron
D. Propagation of the action potential along the sarcolemma
Correct Answer: B. Binding of calcium to troponin C
Rationale: Skeletal muscle contraction requires calcium release
from the sarcoplasmic reticulum. Calcium binds troponin C,
causing tropomyosin to move away from actin's myosin-binding
sites. Depletion of intracellular calcium prevents effective
excitation-contraction coupling.
Exam 2026 | Cardiovascular, Renal,
Respiratory, Endocrine, Neurophysiology & GI
Systems | Practice Questions
Question 1
A healthy adult suddenly stands from a supine position. Within
seconds, arterial blood pressure briefly decreases before
compensatory mechanisms restore it. Which response most
directly mediates the immediate correction?
A. Increased parasympathetic activity to the sinoatrial node
B. Decreased sympathetic activity to systemic arterioles
C. Increased sympathetic activity causing arteriolar
vasoconstriction and increased heart rate
D. Increased secretion of atrial natriuretic peptide
Correct Answer: C. Increased sympathetic activity causing
arteriolar vasoconstriction and increased heart rate
Rationale: Standing causes venous pooling and transiently
decreases venous return, stroke volume, and arterial pressure.
Reduced stretch of carotid sinus and aortic arch baroreceptors
decreases baroreceptor firing, increasing sympathetic and
,decreasing parasympathetic activity. This rapidly increases
heart rate, contractility, and systemic vascular resistance.
Question 2
A patient has a mutation that prevents voltage-gated sodium
channels in skeletal muscle from rapidly inactivating. Which
effect is most likely?
A. Prolonged depolarization and impaired repolarization
B. Complete absence of action potentials
C. Increased resting membrane potential negativity
D. Increased potassium influx during depolarization
Correct Answer: A. Prolonged depolarization and impaired
repolarization
Rationale: Voltage-gated sodium channels normally open
rapidly during depolarization and then inactivate. Failure of
inactivation causes persistent sodium influx, prolonging
depolarization and interfering with normal repolarization and
subsequent action potential generation.
Question 3
,A researcher increases the extracellular concentration of
potassium surrounding a neuron while keeping all other
variables constant. What is the most immediate effect?
A. Hyperpolarization
B. Depolarization
C. Increased chloride influx
D. No change in membrane potential
Correct Answer: B. Depolarization
Rationale: Increasing extracellular potassium reduces the
concentration gradient driving potassium out of the cell. The
equilibrium potential for potassium becomes less negative,
causing the resting membrane potential to become less
negative and therefore depolarized.
Question 4
A patient has severe hypocalcemia. Which change in neuronal
excitability is most likely?
A. Increased threshold for action potential generation
B. Decreased neuronal excitability
C. Increased neuronal excitability due to reduced threshold
potential
D. Complete inhibition of voltage-gated sodium channels
, Correct Answer: C. Increased neuronal excitability due to
reduced threshold potential
Rationale: Extracellular calcium stabilizes voltage-gated sodium
channels. Low extracellular calcium makes these channels
easier to activate, lowering the threshold for action potential
generation and increasing neuromuscular excitability.
Question 5
A skeletal muscle fiber is experimentally stimulated while
intracellular calcium stores are depleted. Which process is most
directly impaired?
A. ATP production by oxidative phosphorylation
B. Binding of calcium to troponin C
C. Release of acetylcholine from the motor neuron
D. Propagation of the action potential along the sarcolemma
Correct Answer: B. Binding of calcium to troponin C
Rationale: Skeletal muscle contraction requires calcium release
from the sarcoplasmic reticulum. Calcium binds troponin C,
causing tropomyosin to move away from actin's myosin-binding
sites. Depletion of intracellular calcium prevents effective
excitation-contraction coupling.
