2026/2027
NURS 5315 Advanced
Pathophysiology Exam Prep
2026/2027 Complete Revision Notes,
Quizzes, and High-Yield Test Bank
Questions
Question 1:
A nursing student is reviewing the phases of the neuronal action potential. Which
sequence correctly represents the order of events?
A. Hyperpolarization → depolarization → repolarization
B. Depolarization → repolarization → hyperpolarization
C. Repolarization → hyperpolarization → depolarization
D. Depolarization → hyperpolarization → repolarization
Correct Answer: B. Depolarization → repolarization → hyperpolarization
Rationale:
The action potential begins with depolarization, where sodium ions (Na⁺) rapidly
enter the cell making the membrane potential more positive. This is followed by
repolarization, during which potassium (K⁺) exits the cell restoring the negative
resting membrane potential. Finally, hyperpolarization may occur briefly when the
membrane becomes more negative than the resting state before stabilizing. The other
options incorrectly order these physiological phases.
Question 2:
What is the primary cellular event during depolarization?
A. Potassium enters the cell
B. Sodium leaves the cell
C. Sodium enters the cell
D. Chloride enters the cell
Correct Answer: C. Sodium enters the cell
Rationale:
Depolarization occurs when voltage-gated sodium channels open, allowing sodium
ions to enter the cell. This makes the intracellular environment more positive, moving
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the membrane potential toward zero. Potassium movement is associated with
repolarization, not depolarization, and chloride ions do not drive this phase.
Question 3:
A neuron fails to generate an action potential unless a specific voltage threshold is
reached. What is the typical threshold range?
A. -90 to -100 mV
B. -70 to -85 mV
C. -55 to -65 mV
D. +10 to +20 mV
Correct Answer: C. -55 to -65 mV
Rationale:
The threshold potential required to initiate an action potential is typically around -55
to -65 mV, meaning the membrane must depolarize by approximately 15–20 mV from
resting potential. Values in other options represent either resting potential or
unrealistic depolarized states.
Question 4:
Which pump is primarily responsible for maintaining sodium and potassium gradients
across the cell membrane?
A. Calcium ATPase
B. Sodium-glucose cotransporter
C. Na⁺/K⁺ ATPase
D. Chloride channel pump
Correct Answer: C. Na⁺/K⁺ ATPase
Rationale:
The Na⁺/K⁺ ATPase pump actively transports sodium out of the cell and potassium
into the cell, maintaining electrochemical gradients essential for excitability. Other
options either transport different ions or do not maintain resting membrane potential.
Question 5:
Resting membrane potential of most excitable cells is approximately:
A. 0 to -10 mV
B. -20 to -40 mV
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C. -70 to -85 mV
D. +30 to +50 mV
Correct Answer: C. -70 to -85 mV
Rationale:
Most neurons and muscle cells maintain a resting membrane potential between -70
and -85 mV, reflecting a stable polarized state. This is maintained by ion gradients
and membrane permeability. Other values represent either depolarized or
physiologically incorrect states.
Question 6:
What defines the absolute refractory period?
A. Cell responds only to weak stimuli
B. Cell responds to strong stimuli only
C. Cell cannot respond to any stimulus
D. Cell is in a hyperexcitable state
Correct Answer: C. Cell cannot respond to any stimulus
Rationale:
During the absolute refractory period, sodium channels are inactivated and the cell
cannot initiate another action potential regardless of stimulus strength. The relative
refractory period allows response only to strong stimuli, making the other options
incorrect.
Question 7:
Hyperpolarization is best defined as:
A. Membrane potential becomes less negative than normal
B. Membrane potential becomes more positive than zero
C. Membrane potential becomes more negative than resting level
D. Sodium influx dominates the cell
Correct Answer: C. Membrane potential becomes more negative than resting
level
Rationale:
Hyperpolarization occurs when the membrane potential becomes more negative than
the resting level (e.g., below -85 mV), making the cell less excitable. This increases
the distance from threshold, reducing likelihood of firing.
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Question 8:
Hypokalemia affects cellular excitability by causing:
A. Depolarization and hyperexcitability
B. Hyperpolarization and reduced excitability
C. No change in membrane potential
D. Permanent depolarization
Correct Answer: B. Hyperpolarization and reduced excitability
Rationale:
In hypokalemia, extracellular potassium decreases, making the inside of the cell more
negative (hyperpolarized). This increases the distance to threshold, reducing
excitability and impairing neuromuscular function.
Question 9:
Hyperkalemia causes which membrane effect?
A. Hyperpolarization
B. Hypopolarization (depolarization)
C. No change in resting potential
D. Complete inhibition of sodium channels
Correct Answer: B. Hypopolarization (depolarization)
Rationale:
In hyperkalemia, extracellular potassium increases, making the resting membrane
potential less negative (hypopolarized). This increases excitability initially but may
eventually prevent action potential generation in severe cases.
Question 10:
Hypocalcemia increases excitability because it:
A. Stabilizes sodium channels
B. Decreases sodium permeability
C. Increases sodium permeability
D. Blocks potassium channels
Correct Answer: C. Increases sodium permeability
Rationale:
Low calcium levels reduce membrane stability and increase sodium permeability,
NURS 5315 Advanced
Pathophysiology Exam Prep
2026/2027 Complete Revision Notes,
Quizzes, and High-Yield Test Bank
Questions
Question 1:
A nursing student is reviewing the phases of the neuronal action potential. Which
sequence correctly represents the order of events?
A. Hyperpolarization → depolarization → repolarization
B. Depolarization → repolarization → hyperpolarization
C. Repolarization → hyperpolarization → depolarization
D. Depolarization → hyperpolarization → repolarization
Correct Answer: B. Depolarization → repolarization → hyperpolarization
Rationale:
The action potential begins with depolarization, where sodium ions (Na⁺) rapidly
enter the cell making the membrane potential more positive. This is followed by
repolarization, during which potassium (K⁺) exits the cell restoring the negative
resting membrane potential. Finally, hyperpolarization may occur briefly when the
membrane becomes more negative than the resting state before stabilizing. The other
options incorrectly order these physiological phases.
Question 2:
What is the primary cellular event during depolarization?
A. Potassium enters the cell
B. Sodium leaves the cell
C. Sodium enters the cell
D. Chloride enters the cell
Correct Answer: C. Sodium enters the cell
Rationale:
Depolarization occurs when voltage-gated sodium channels open, allowing sodium
ions to enter the cell. This makes the intracellular environment more positive, moving
,2026/2027
the membrane potential toward zero. Potassium movement is associated with
repolarization, not depolarization, and chloride ions do not drive this phase.
Question 3:
A neuron fails to generate an action potential unless a specific voltage threshold is
reached. What is the typical threshold range?
A. -90 to -100 mV
B. -70 to -85 mV
C. -55 to -65 mV
D. +10 to +20 mV
Correct Answer: C. -55 to -65 mV
Rationale:
The threshold potential required to initiate an action potential is typically around -55
to -65 mV, meaning the membrane must depolarize by approximately 15–20 mV from
resting potential. Values in other options represent either resting potential or
unrealistic depolarized states.
Question 4:
Which pump is primarily responsible for maintaining sodium and potassium gradients
across the cell membrane?
A. Calcium ATPase
B. Sodium-glucose cotransporter
C. Na⁺/K⁺ ATPase
D. Chloride channel pump
Correct Answer: C. Na⁺/K⁺ ATPase
Rationale:
The Na⁺/K⁺ ATPase pump actively transports sodium out of the cell and potassium
into the cell, maintaining electrochemical gradients essential for excitability. Other
options either transport different ions or do not maintain resting membrane potential.
Question 5:
Resting membrane potential of most excitable cells is approximately:
A. 0 to -10 mV
B. -20 to -40 mV
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C. -70 to -85 mV
D. +30 to +50 mV
Correct Answer: C. -70 to -85 mV
Rationale:
Most neurons and muscle cells maintain a resting membrane potential between -70
and -85 mV, reflecting a stable polarized state. This is maintained by ion gradients
and membrane permeability. Other values represent either depolarized or
physiologically incorrect states.
Question 6:
What defines the absolute refractory period?
A. Cell responds only to weak stimuli
B. Cell responds to strong stimuli only
C. Cell cannot respond to any stimulus
D. Cell is in a hyperexcitable state
Correct Answer: C. Cell cannot respond to any stimulus
Rationale:
During the absolute refractory period, sodium channels are inactivated and the cell
cannot initiate another action potential regardless of stimulus strength. The relative
refractory period allows response only to strong stimuli, making the other options
incorrect.
Question 7:
Hyperpolarization is best defined as:
A. Membrane potential becomes less negative than normal
B. Membrane potential becomes more positive than zero
C. Membrane potential becomes more negative than resting level
D. Sodium influx dominates the cell
Correct Answer: C. Membrane potential becomes more negative than resting
level
Rationale:
Hyperpolarization occurs when the membrane potential becomes more negative than
the resting level (e.g., below -85 mV), making the cell less excitable. This increases
the distance from threshold, reducing likelihood of firing.
, 2026/2027
Question 8:
Hypokalemia affects cellular excitability by causing:
A. Depolarization and hyperexcitability
B. Hyperpolarization and reduced excitability
C. No change in membrane potential
D. Permanent depolarization
Correct Answer: B. Hyperpolarization and reduced excitability
Rationale:
In hypokalemia, extracellular potassium decreases, making the inside of the cell more
negative (hyperpolarized). This increases the distance to threshold, reducing
excitability and impairing neuromuscular function.
Question 9:
Hyperkalemia causes which membrane effect?
A. Hyperpolarization
B. Hypopolarization (depolarization)
C. No change in resting potential
D. Complete inhibition of sodium channels
Correct Answer: B. Hypopolarization (depolarization)
Rationale:
In hyperkalemia, extracellular potassium increases, making the resting membrane
potential less negative (hypopolarized). This increases excitability initially but may
eventually prevent action potential generation in severe cases.
Question 10:
Hypocalcemia increases excitability because it:
A. Stabilizes sodium channels
B. Decreases sodium permeability
C. Increases sodium permeability
D. Blocks potassium channels
Correct Answer: C. Increases sodium permeability
Rationale:
Low calcium levels reduce membrane stability and increase sodium permeability,
