Chapter 2

Identify the four major structures that compose a neuron.

When the membrane is at rest, are the sodium ions more concentrated inside the cell or outside? Where are the potassium ions more concentrated?

When the membrane is at rest, what tends to drive the potassium ions out of the cell? What tends to draw them into the cell?

Which kind of glia cell wraps around the synaptic terminals of axons?

What is the difference between a hyperpolarization and a depolarization?

What is one major advantage of having a blood-brain barrier?

What is the relationship between the threshold and an action potential?

What is a disadvantage of the blood-brain barrier?

During the rise of the action potential, do sodium ions move into the cell or out of it? Why?

As the membrane reaches the peak of the action potential, what ionic movement brings the potential down to the original resting potential?

State the all-or-none law.

Suppose researchers find that axon \(A\) can produce up to 1,000 action potentials per second (at least briefly, with maximum stimulation), but axon \(\mathrm{B}\) can never produce more than 200 per second (regardless of the strength of the stimulus). What could we conclude about the refractory periods of the two axons?