Nerve Impulse

The exhibit demonstrates fundamental properties of nerve cell transmission.
In the Plexiglas box below is a piece of crayfish nerve cord. Set the stimulation level to zero. Press and hold the stimulator button. Slowly increase the stimulation level and watch the oscilloscope. Notice that as you increase the stimulation level , the height of the pulse at the left edge of the oscilloscope face increases. At a certain level, or “threshold”, bumps will follow the initial stimulating spike. The bumps are nerve impulses traveling the length of the nerve. They are triggered by the electrical pulse which is sent to the nerve through the stimulating electrode. The electrical pulse and impulses are detected at the recording electrode. The oscilloscope displays this activity.