Neuron Function
How does a signal travel across and between
neurons?
Why?
Just as the coaxial cables that run down your street or through your house carry television and
Internet signals, the job of a neuron is to move an electrical signal from one place to another in
order to send sen-sory messages throughout the body. In a previous activity you saw how a
membrane potential is formed both at rest and during an inflow of ions. In this activity you
will explore how changes in membrane potentials can propagate a signal down the axon of a
neuron.
1. Which of the gated embedded proteins in Model 1 allow sodium ions ( ) through the membrane?
Gates A, B, D and Fallow sodium ions through the membrane
2. Which of the gated embedded proteins in Model 1 allow potassium ions ( ) through the
membrane?
Gates C, E and G allow potassium ions through the membrane
3. The neuron illustrated in Model 1 has received a signal from either a sensory cell (taste bud, skin
cell, retinal cell, etc.) or from another neuron. What evidence do you find in diagram 1
of themodel that indicates a signal has been received?
A signal ligand has bound to the ligand gated embedded protein and the gate has opened
4. In diagram 2 of Model 1, gated embedded protein B has opened. Was this opening triggered by
the arrival of a signal ligand? If no, propose an alternate stimulus that might have
triggered thegate to open.
No, diagram 2 does not show a ligand bound to embedded protein B. The gate may have
Opened because of the change in membrane potential from the flood of ions nearby.
5. Consider Model 1.
a. When a signal moves down the axon of the neuron, which direction do sodium
ions movethrough the voltage-gated embedded proteins?
Sodium ions move into the cell when the sodium gates are opened
b. What does the movement of sodium ions across the membrane do to the membrane
potentialnear the open embedded protein?
The membrane potential increases (gets more positive) as the sodium ions move into the cell
6. Consider Model 1.
a. When a signal moves through the axon of the neuron, which direction do
, potassium ions move through the voltage-gated embedded proteins?
Potassium ions move out of the cell when the potassium gates are opened
b. What does the movement of potassium ions across the membrane do to the membrane potent
near the open embedded protein?
The membrane potential decreases (gets more negative) as the potassium ions move out of the cell
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How does a signal travel across and between
neurons?
Why?
Just as the coaxial cables that run down your street or through your house carry television and
Internet signals, the job of a neuron is to move an electrical signal from one place to another in
order to send sen-sory messages throughout the body. In a previous activity you saw how a
membrane potential is formed both at rest and during an inflow of ions. In this activity you
will explore how changes in membrane potentials can propagate a signal down the axon of a
neuron.
1. Which of the gated embedded proteins in Model 1 allow sodium ions ( ) through the membrane?
Gates A, B, D and Fallow sodium ions through the membrane
2. Which of the gated embedded proteins in Model 1 allow potassium ions ( ) through the
membrane?
Gates C, E and G allow potassium ions through the membrane
3. The neuron illustrated in Model 1 has received a signal from either a sensory cell (taste bud, skin
cell, retinal cell, etc.) or from another neuron. What evidence do you find in diagram 1
of themodel that indicates a signal has been received?
A signal ligand has bound to the ligand gated embedded protein and the gate has opened
4. In diagram 2 of Model 1, gated embedded protein B has opened. Was this opening triggered by
the arrival of a signal ligand? If no, propose an alternate stimulus that might have
triggered thegate to open.
No, diagram 2 does not show a ligand bound to embedded protein B. The gate may have
Opened because of the change in membrane potential from the flood of ions nearby.
5. Consider Model 1.
a. When a signal moves down the axon of the neuron, which direction do sodium
ions movethrough the voltage-gated embedded proteins?
Sodium ions move into the cell when the sodium gates are opened
b. What does the movement of sodium ions across the membrane do to the membrane
potentialnear the open embedded protein?
The membrane potential increases (gets more positive) as the sodium ions move into the cell
6. Consider Model 1.
a. When a signal moves through the axon of the neuron, which direction do
, potassium ions move through the voltage-gated embedded proteins?
Potassium ions move out of the cell when the potassium gates are opened
b. What does the movement of potassium ions across the membrane do to the membrane potent
near the open embedded protein?
The membrane potential decreases (gets more negative) as the potassium ions move out of the cell
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