Capstone: Charges In the Nervous System

GABA is the major inhibitory neurotransmitter in the central nervous system. It exerts its effect by opening ion channels that allow for negatively charged chloride ions to enter the cell and lower the resting potential. This makes cells less likely to reach threshold and results in the generation of fewer action potentials by excitable cells. Which of the following explains why chloride ions enter the cell?

Myelin functions to prevent the dissipation of action potentials as they propagate down an axon by blocking ions from exiting. This property speeds transmission rates within the nervous system. However, not all axons are myelinated and the table below shows the conduction speed for 4 types of nerves and their myelination status.

Based on this information which of the following answer choices correctly ranks the different nerves from the highest resistivity to lowest resistivity?

During depolarization, approximately 6.00 x 10¹¹ Na^{${}^{}$} per meter enter the neuron, each with charge +e, enter the axon. (e = 1.6 x 10^-19 C). What amount of charge in coulombs enters a 2.0 mm segment of an axon during depolarization?