ACE 2026/2027NEURON FUNCTION EXAMINATION
COMPLETE STUDY GUIDE WITH COMPREHENSIVE
QUESTIONS AND ANSWERS
◍ Define repolarization.
Answer: Occurs immediately after depolarization and is the movement of
positively charged ions back to the outside of the cell, returning the cell
back to its original polarized state. A cell must repolarize before it can
depolarize again.
◍ At what potential are the potassium ion gates closed?.
Answer: The potassium ion gates close when the membrane potential
reaches -80 mV
◍ Define depolarized.
Answer: When an action potential is in progress the cell membrane is
depolarized. The potential difference between the two sides of the
membrane is decreased
◍ looking at model 1at what potential are the sodium ion gates closed.
Answer: the sodium ion gates close when the membrane potential reaches
+35 mV
◍ Which of the gated embedded proteins in Model 1 allow potassium ions (
triangles ) through the membrane?.
Answer: Gates C, E, and G allow potassium ions through the membrane
◍ The neuron illustrated in Model 1 has received a signal from either a sensory
cell (taste bud, skincell, retinal cell, etc.) or from another neuron. What
evidence do you find in diagram 1 of themodel that indicates a signal has
been received?.
, Answer: A signal Ligand has bound to the ligand-gated embedded protein
and the gate has opened
◍ C. Could another signal be sent down the length of the neuron cell if the
sodium ions and potassium ions were not returned to their original
position?. Answer: No, the neuron cannot transmit another signal until the
ions are returned because the concentration gradients for the ions are going
in the wrong direction
◍ Describe how the electrical signal in the neuron moves.
Answer: the gates open one at a time from left to right in model 1. the high
concentration of sodium ions inside the cell moves from left to right in
model 1
◍ Schwann cells.
Answer: Form myelin sheath in the PNS; provide myelin insulation to
neurons in the peripheral nervous system
◍ Neurotransmitters.
Answer: Chemicals released at the end of an axon terminal that diffuse
across the synapse and transfer the nerve impulse to another nerve, muscle,
or gland
◍ according to model 1 ,what is the membrane potential near sodium ion gates
during the refractory period ?.
Answer: the lowest potential in model 1 is -80mv
◍ Astrocytes.
Answer: Largest and most numerous neuroglial cells; anchor neurons to
blood capillaries and provide oxygen and nutrients
◍ When a signal moves down the axon of the neuron, which direction do
sodium ions movethrough the voltage-gated embedded proteins?.
Answer: sodium ions move into the cell when the sodium gates are opened
COMPLETE STUDY GUIDE WITH COMPREHENSIVE
QUESTIONS AND ANSWERS
◍ Define repolarization.
Answer: Occurs immediately after depolarization and is the movement of
positively charged ions back to the outside of the cell, returning the cell
back to its original polarized state. A cell must repolarize before it can
depolarize again.
◍ At what potential are the potassium ion gates closed?.
Answer: The potassium ion gates close when the membrane potential
reaches -80 mV
◍ Define depolarized.
Answer: When an action potential is in progress the cell membrane is
depolarized. The potential difference between the two sides of the
membrane is decreased
◍ looking at model 1at what potential are the sodium ion gates closed.
Answer: the sodium ion gates close when the membrane potential reaches
+35 mV
◍ Which of the gated embedded proteins in Model 1 allow potassium ions (
triangles ) through the membrane?.
Answer: Gates C, E, and G allow potassium ions through the membrane
◍ The neuron illustrated in Model 1 has received a signal from either a sensory
cell (taste bud, skincell, retinal cell, etc.) or from another neuron. What
evidence do you find in diagram 1 of themodel that indicates a signal has
been received?.
, Answer: A signal Ligand has bound to the ligand-gated embedded protein
and the gate has opened
◍ C. Could another signal be sent down the length of the neuron cell if the
sodium ions and potassium ions were not returned to their original
position?. Answer: No, the neuron cannot transmit another signal until the
ions are returned because the concentration gradients for the ions are going
in the wrong direction
◍ Describe how the electrical signal in the neuron moves.
Answer: the gates open one at a time from left to right in model 1. the high
concentration of sodium ions inside the cell moves from left to right in
model 1
◍ Schwann cells.
Answer: Form myelin sheath in the PNS; provide myelin insulation to
neurons in the peripheral nervous system
◍ Neurotransmitters.
Answer: Chemicals released at the end of an axon terminal that diffuse
across the synapse and transfer the nerve impulse to another nerve, muscle,
or gland
◍ according to model 1 ,what is the membrane potential near sodium ion gates
during the refractory period ?.
Answer: the lowest potential in model 1 is -80mv
◍ Astrocytes.
Answer: Largest and most numerous neuroglial cells; anchor neurons to
blood capillaries and provide oxygen and nutrients
◍ When a signal moves down the axon of the neuron, which direction do
sodium ions movethrough the voltage-gated embedded proteins?.
Answer: sodium ions move into the cell when the sodium gates are opened
