Nurs 5315 Ultimate Exam 1 Questions and
Answers with Verified Solutions | Latest
Updated 2026
Resting Potential The neuron is in a resting state with a
voltage of
approximately -70 mV, maintained by the
sodium-
potassium pump.
Threshold A certain threshold (usually around -55
mV) is
reached when a stimulus causes slight
depolarization, triggering an action
potential.
Depolarization Voltage-gated sodium channels open
rapidly,
allowing Na■ ions to rush into the cell,
causing the
membrane potential to reach up to +30
mV.
Peak Phase At the peak of the action potential, the
inactivation
gates of sodium channels close, stopping
Na■
influx, while voltage-gated potassium
channels
open.
,Repolarization K■ ions flow out of the cell through
opened
potassium channels, making the inside of
the cell
more negative and returning towards
resting
potential.
Hyperpolarization The potassium channels are slow to close,
causing
an overshoot where the membrane
potential
becomes more negative than the resting
potential.
Return to Resting Potential The sodium-potassium pump restores the
resting
potential by transporting Na■ ions out and
K■ ions
back into the neuron.
Calcium Imbalance Calcium imbalances can significantly affect
the
action potential of neurons.
Hypercalcemia High extracellular calcium levels can
increase the
threshold required to initiate an action
potential
and enhance synaptic release.
, Hypocalcemia Low extracellular calcium reduces the
threshold for
action potential initiation, increasing
excitability
and leading to symptoms like muscle
spasms.
Potassium Imbalance Potassium imbalances can also
significantly affect
the action potential of neurons.
Hyperkalemia High potassium levels decrease the resting
membrane potential, bringing it closer to
the
threshold but can impair action potential
firing over
time.
Hypokalemia Low potassium levels make the membrane
potential more negative, reducing
excitability and
making it harder for neurons to fire action
potentials.
Muscle Weakness Chronic depolarization from hyperkalemia
can
lead to long-term paralysis or weakness
due to
inactivation of sodium channels.
Answers with Verified Solutions | Latest
Updated 2026
Resting Potential The neuron is in a resting state with a
voltage of
approximately -70 mV, maintained by the
sodium-
potassium pump.
Threshold A certain threshold (usually around -55
mV) is
reached when a stimulus causes slight
depolarization, triggering an action
potential.
Depolarization Voltage-gated sodium channels open
rapidly,
allowing Na■ ions to rush into the cell,
causing the
membrane potential to reach up to +30
mV.
Peak Phase At the peak of the action potential, the
inactivation
gates of sodium channels close, stopping
Na■
influx, while voltage-gated potassium
channels
open.
,Repolarization K■ ions flow out of the cell through
opened
potassium channels, making the inside of
the cell
more negative and returning towards
resting
potential.
Hyperpolarization The potassium channels are slow to close,
causing
an overshoot where the membrane
potential
becomes more negative than the resting
potential.
Return to Resting Potential The sodium-potassium pump restores the
resting
potential by transporting Na■ ions out and
K■ ions
back into the neuron.
Calcium Imbalance Calcium imbalances can significantly affect
the
action potential of neurons.
Hypercalcemia High extracellular calcium levels can
increase the
threshold required to initiate an action
potential
and enhance synaptic release.
, Hypocalcemia Low extracellular calcium reduces the
threshold for
action potential initiation, increasing
excitability
and leading to symptoms like muscle
spasms.
Potassium Imbalance Potassium imbalances can also
significantly affect
the action potential of neurons.
Hyperkalemia High potassium levels decrease the resting
membrane potential, bringing it closer to
the
threshold but can impair action potential
firing over
time.
Hypokalemia Low potassium levels make the membrane
potential more negative, reducing
excitability and
making it harder for neurons to fire action
potentials.
Muscle Weakness Chronic depolarization from hyperkalemia
can
lead to long-term paralysis or weakness
due to
inactivation of sodium channels.
