NURS 5315 ADVANCED PATHOPHYSIOLOGY
EXAM 1 COMPREHENSIVE STUDY GUIDE 2026
PRACTICE QUESTIONS AND ACCURATE
ANSWERS GRADED A+
◉ Depolarization. Answer: movement of the intracellular charge
towards zero (more positive charge)
Voltage gated Na channels open and allow Na to enter the cell ->
voltage inside the cell moves towards zero
◉ Repolarization. Answer: Once the intracellular charge reaches
zero, the negative polarity of the inside of the cell is restored back to
its baseline of -70 to -85 mV
-Na channels close, K channels open
◉ Hyperpolarization. Answer: when the cell's resting membrane
potential is greater than -85mV. Is less excitable, because there is a
greater distance between the resting membrane potential and the
threshold potential.
◉ In order for the action potential to be sucessful. Answer: t has to
depolarize by 15-20 mV (threshold potential) to reach -55 to -65 mV.
,◉ An alteration in action potential may result from. Answer:
neurologic diseases, muscle disease or electrolyte imbalances.
◉ What is the main protein responsible for maintaining the correct
balance of extracellular Na and intracellular K, which is needed for
cellular excitation and membrane conductivity.. Answer: Na+-K+
ATPase
◉ Resting membrane potential. Answer: when the cell is in a
nonexcited state and is at -70 to -85 mV.
◉ Refractory Period. Answer: is a period of time during most of the
action potential which the cell membrane resists stimulation and it
cannot depolarize
◉ Absolute refractory period. Answer: occurs when the membrane
will not respond to ANY stimulus no matter how strong.
◉ Relative Refractory Period. Answer: occurs when the membrane is
repolarizing and will only respond to a very strong stimulus.
◉ Hyperpolarized. Answer: when the cell's resting membrane
potential is greater than -85mV.
,Is less excitable, because there is a greater distance between the
resting membrane potential and the threshold potential.
◉ Hypopolarized. Answer: when the cell's resting membrane
potential is closer to zero, for instance it is -65mV.
Is more excitable because the resting membrane potential is closer
to the threshold potential, there is less distance between them.
◉ Action potential altered by hypokalemia. Answer: (serum outside
of cell is low)
-Hyperpolarized (cell becomes more negative, ex: -100)
-Affects the resting membrane potential of cells
-The cell is less likely to depolarize and transmit impulses
Can cause a decrease in neuromuscular excitability and leads to
weakness, smooth muscle atony, paresthesias, and cardiac
dysrhythmias
◉ Action potential altered by hyperkalemia. Answer: Hypopolarized
-Also has an effect on the resting membrane potential
-If the ECF potassium increases without any change in the ICF
potassium levels, the resting membrane potential of the cell
becomes more positive.
-The cells are more excitable and conduct impulses more easily and
more quickly because the resting membrane potential is closer to
, the threshold potential. Therefore, the person will have peak T
waves on EKG.
-As potassium rises, the resting membrane potential will continue to
become more positive and it will eventually become equal to the
threshold potential. As this happens the EKG will show a widening
QRS complex. If the resting membrane potential equals the
threshold potential, an action potential will not be generated and
cardiac standstill will occur. Paralysis and paresthesias may also
occur.
◉ Action potential altered by hypocalcemia. Answer: -Causes an
increase in the cell permeability to Na causing a progressive
depolarization
-Causes the RMP and the TP to be closer to one another & making it
easier to initiate an action potential - the cells are more excitable.
-Results in tetany, hyperreflexia, circumoral paresthesias, seizures,
dysrhythmias
◉ Action potential altered by hypercalcemia. Answer: -Causes a
decrease in cell permeability to Na
-Causes the RMP and the TP to increase in distance - the cells are
less excitable and requires more of a stimulus to initiate an action
potential.
-Leads to weakness, hyporeflexia, fatigue, lethargy, confusion,
encephalopathy, a shortened QT segment and depressed widened T
waves on EKG.
EXAM 1 COMPREHENSIVE STUDY GUIDE 2026
PRACTICE QUESTIONS AND ACCURATE
ANSWERS GRADED A+
◉ Depolarization. Answer: movement of the intracellular charge
towards zero (more positive charge)
Voltage gated Na channels open and allow Na to enter the cell ->
voltage inside the cell moves towards zero
◉ Repolarization. Answer: Once the intracellular charge reaches
zero, the negative polarity of the inside of the cell is restored back to
its baseline of -70 to -85 mV
-Na channels close, K channels open
◉ Hyperpolarization. Answer: when the cell's resting membrane
potential is greater than -85mV. Is less excitable, because there is a
greater distance between the resting membrane potential and the
threshold potential.
◉ In order for the action potential to be sucessful. Answer: t has to
depolarize by 15-20 mV (threshold potential) to reach -55 to -65 mV.
,◉ An alteration in action potential may result from. Answer:
neurologic diseases, muscle disease or electrolyte imbalances.
◉ What is the main protein responsible for maintaining the correct
balance of extracellular Na and intracellular K, which is needed for
cellular excitation and membrane conductivity.. Answer: Na+-K+
ATPase
◉ Resting membrane potential. Answer: when the cell is in a
nonexcited state and is at -70 to -85 mV.
◉ Refractory Period. Answer: is a period of time during most of the
action potential which the cell membrane resists stimulation and it
cannot depolarize
◉ Absolute refractory period. Answer: occurs when the membrane
will not respond to ANY stimulus no matter how strong.
◉ Relative Refractory Period. Answer: occurs when the membrane is
repolarizing and will only respond to a very strong stimulus.
◉ Hyperpolarized. Answer: when the cell's resting membrane
potential is greater than -85mV.
,Is less excitable, because there is a greater distance between the
resting membrane potential and the threshold potential.
◉ Hypopolarized. Answer: when the cell's resting membrane
potential is closer to zero, for instance it is -65mV.
Is more excitable because the resting membrane potential is closer
to the threshold potential, there is less distance between them.
◉ Action potential altered by hypokalemia. Answer: (serum outside
of cell is low)
-Hyperpolarized (cell becomes more negative, ex: -100)
-Affects the resting membrane potential of cells
-The cell is less likely to depolarize and transmit impulses
Can cause a decrease in neuromuscular excitability and leads to
weakness, smooth muscle atony, paresthesias, and cardiac
dysrhythmias
◉ Action potential altered by hyperkalemia. Answer: Hypopolarized
-Also has an effect on the resting membrane potential
-If the ECF potassium increases without any change in the ICF
potassium levels, the resting membrane potential of the cell
becomes more positive.
-The cells are more excitable and conduct impulses more easily and
more quickly because the resting membrane potential is closer to
, the threshold potential. Therefore, the person will have peak T
waves on EKG.
-As potassium rises, the resting membrane potential will continue to
become more positive and it will eventually become equal to the
threshold potential. As this happens the EKG will show a widening
QRS complex. If the resting membrane potential equals the
threshold potential, an action potential will not be generated and
cardiac standstill will occur. Paralysis and paresthesias may also
occur.
◉ Action potential altered by hypocalcemia. Answer: -Causes an
increase in the cell permeability to Na causing a progressive
depolarization
-Causes the RMP and the TP to be closer to one another & making it
easier to initiate an action potential - the cells are more excitable.
-Results in tetany, hyperreflexia, circumoral paresthesias, seizures,
dysrhythmias
◉ Action potential altered by hypercalcemia. Answer: -Causes a
decrease in cell permeability to Na
-Causes the RMP and the TP to increase in distance - the cells are
less excitable and requires more of a stimulus to initiate an action
potential.
-Leads to weakness, hyporeflexia, fatigue, lethargy, confusion,
encephalopathy, a shortened QT segment and depressed widened T
waves on EKG.
