BIO 365S Lecture Notes - Lecture 6: Axon Hillock, Oligodendrocyte, Neuroglia

When the na-channels of an axon open, what would happen?

a. Saltatory conduction

b. repolarization

c. hyperpolarization

d. Na+ ions flow into the neuron

e. Na+ ions flow out of the neuron

When the K-channels in the axon open, what would happen?

a. depolarize the neuron

b. block action potential

c. maintain the membrane potential

d. repolarize the neuron

e. release neurotransmitters.

When a neuron is depolarized closer to the threshold, the neuron is

a. more excitable

b. less excitable

c. more inhibitory

d. inactivated

e. blocked from finding action potentials

Signals of varying strength travel through the nervous system -either as incoming sensory input or commands to effectors to dowork.

Explain how signal strength is varied during the followingevents:

a. during synaptic transmission
b. during processing of incoming signals from the receiving regionof a neuron to the axon hillock
c. during action potential propagation along the axon

These questions are based from an online simulation of action potentials.

1)Why is so much more stimulus current needed to depolarize the squid axon than the membrane patch (.0001cm^2).

2)The spatial extent of the action potential is quite large. Explain why in terms of conduction velocity, and how it would change as a function of axon diameter.

3)The leakage potential of a cell is set to -20mV, and the stimulus current to 0 nA. Hypothetically, If a neuron or other excitable cell had this property, how would it behave? What biological function might it perform – can you think of an example of such a cell?