4. Ion channels are at the heart of neuron physiology. Using the parameters of location, trigger for opening the channel, and ion selectivity, compare and contrast ligand-gated channels from
voltage-gated channels.
5. Saltatory conduction is a phrase used to describe how an action potential travels down a neuron,
“jumping" from one node of Ranvier to the next. How does the absolute refractory period of
voltage-gated channels facilitate this action potential movement down an axon towards the axon
terminal and not back to the axon hillock?
6. Hyperpolarization is a normal phase of the action potential, but is also a mechanism by which a
neuron can be inhibited from signaling. Describe the ion movement that normally causes the
hyperpolarization at the end of an action potential. In a resting ion (not firing an action
potential), describe one ion movement that would hyperpolarize a neuron. Mentioning threshold,
why would this serve to inhibit that neuron from firing an action potential?