BIO 2301 HUMAN PHYSIOLOGY
CERTIFICATION REVIEW SCRIPT 2026
ACCURATE Q&A COLLECTION
◉Hyperpolarization. Answer: - During repolarization, the charge
actually dips lower than the RMP
- The Na/K pump will pump the sodium out and the potassium in to
get it back to its RMP
◉What causes more stimulation of the postsynaptic neuron?.
Answer: A greater frequency of action potentials
◉Voltage gated channels. Answer: - Present on the axon cell
membrane
- Normally kept closed unless a change in voltage occurs - will open
when it meets the threshold (-55 mV)
- Voltage gated Na and K channels
◉Steps of the action potential. Answer: 1. Threshold: -55mV
threshold value is met, resulting in the voltage gated Na channels
opening
,2. Sodium flow: Na flows into the axon through through the open
voltage gated Na channels - depolarization occurs and the charge
goes to +30 mV causing the voltage gated Na channels to close and
the voltage gated K channels to open
3. Potassium flow: K flows out of the axon through the open voltage
gated K channels - repolarization occurs and the charge goes to -70
mV
4. Sodium potassium ATPase: the Na/K pump will pump the Na back
out and the K back in to the axon so the axon can be ready to have
another action potential
◉Action potential. Answer: - All or none, meaning, once the
threshold is reached, an action potential will occur
- The size or strength of the stimulus will not affect the size or
duration of the AP
- Can only travel away from the site of initiation
◉Continuous action potentials. Answer: - Action potentials that
occur on non-myelinated axons
- AP are produced segment to segment down the entire length of the
axon
- Slow rate of conduction
◉Saltatory action potentials. Answer: - Action potentials that occur
on mylinated axons
, - Nodes of Ranvier allow sodium and potassium to cross the
membrane every 1-2mm so AP can jump from node to node
- Must faster rate of conduction
◉Graded potential. Answer: - A message within a neuron - does not
travel through the nervous system
- Decremental
- Can vary in size
- Can be depolarizing/excitatory or hyperpolarizing/inhibitory
- Occur until the threshold is reached
- Can cause an action potential if it is a depolarization that causes
the membrane voltage to reach the -55mV threshold value - this
often requires EPSPs from several neurons to reach the threshold
and produce an action potential
◉Action potential propagation. Answer: The action potential
traveling down the axon towards the axonal terminals
◉Role of passive current flow. Answer: - Once the Na enters the
axon, most of it will be pumped back out by the Na/K pump
- Some of the Na will flow over within the axon to the next region,
causing depolarization there and the action potential to begin in that
region
- This allows the action potential to travel down the axon
CERTIFICATION REVIEW SCRIPT 2026
ACCURATE Q&A COLLECTION
◉Hyperpolarization. Answer: - During repolarization, the charge
actually dips lower than the RMP
- The Na/K pump will pump the sodium out and the potassium in to
get it back to its RMP
◉What causes more stimulation of the postsynaptic neuron?.
Answer: A greater frequency of action potentials
◉Voltage gated channels. Answer: - Present on the axon cell
membrane
- Normally kept closed unless a change in voltage occurs - will open
when it meets the threshold (-55 mV)
- Voltage gated Na and K channels
◉Steps of the action potential. Answer: 1. Threshold: -55mV
threshold value is met, resulting in the voltage gated Na channels
opening
,2. Sodium flow: Na flows into the axon through through the open
voltage gated Na channels - depolarization occurs and the charge
goes to +30 mV causing the voltage gated Na channels to close and
the voltage gated K channels to open
3. Potassium flow: K flows out of the axon through the open voltage
gated K channels - repolarization occurs and the charge goes to -70
mV
4. Sodium potassium ATPase: the Na/K pump will pump the Na back
out and the K back in to the axon so the axon can be ready to have
another action potential
◉Action potential. Answer: - All or none, meaning, once the
threshold is reached, an action potential will occur
- The size or strength of the stimulus will not affect the size or
duration of the AP
- Can only travel away from the site of initiation
◉Continuous action potentials. Answer: - Action potentials that
occur on non-myelinated axons
- AP are produced segment to segment down the entire length of the
axon
- Slow rate of conduction
◉Saltatory action potentials. Answer: - Action potentials that occur
on mylinated axons
, - Nodes of Ranvier allow sodium and potassium to cross the
membrane every 1-2mm so AP can jump from node to node
- Must faster rate of conduction
◉Graded potential. Answer: - A message within a neuron - does not
travel through the nervous system
- Decremental
- Can vary in size
- Can be depolarizing/excitatory or hyperpolarizing/inhibitory
- Occur until the threshold is reached
- Can cause an action potential if it is a depolarization that causes
the membrane voltage to reach the -55mV threshold value - this
often requires EPSPs from several neurons to reach the threshold
and produce an action potential
◉Action potential propagation. Answer: The action potential
traveling down the axon towards the axonal terminals
◉Role of passive current flow. Answer: - Once the Na enters the
axon, most of it will be pumped back out by the Na/K pump
- Some of the Na will flow over within the axon to the next region,
causing depolarization there and the action potential to begin in that
region
- This allows the action potential to travel down the axon
