Challenge Prompts for your Notebooks: Answer in complete sentence or write the question above your answer.
• If sodium and potassium ions are both positively charged, what causes the negative membrane
potential in a resting neuron?
• What happens if you try to stimulate the neuron right after the action potential reaches the end
of the neuron? Why? What must happen to be able to stimulate the neuron again?
•What is the difference between a gated ion channel and a leak channel? Explain the role of
each type of channel in neuronal cell function.
•Explain the sequence in which ion channels open and close to propagate an action potential.
• Draw a sketch of the Potential Chart that shows an action potential. Label the chart to show
where sodium and potassium gated channels open and close.
• What happens to the concentration of sodium and potassium ions inside the cell when the
neuron is stimulated? How does this concentration change result in an action potential?
• In the cell, where does the greatest change in ion concentration take place when the neuron is
stimulated? Explain how this allows an action potential to be propagated down a neuron.