REFRACTORY PERIOD

A supramaximal stimulus voltage is used throughout the experiment.

The nerve is stimulated with two consecutive supramaximal stimuli. The stimulus interval is selected by clicking a button on the stimulator panel.

The amplitude of the first (H1) and second (H2) compound action potentials resulting from the two stimuli should be measured.

ASSIGNMENT TWO

After the experiment...

1. Draw a graph of the amplitudes of H1 and H2 in mV (y-axis) versus stimulus interval in ms (x-axis).
2. Explain why the amplitude of H1 does not change.
3. Explain the initial decrease in, and eventual disappearance of, the second action potential (H2) as the stimulus interval is decreased.
4. What is the ionic basis of the refractory period?