The Nerve Impulse
“Let’s start our exploration of the neuron by looking at how it communicates. The primary way that one neuron talks to another is via the nerve impulse, which moves information along the length of the axon from the axon hillock to the axon terminals. Because the axon is relatively long, the nerve impulse is the nervous system’s method for transporting messages over long distances, say from the top of your head to muscles in your feet.
“I’ve got a little demonstration for you to help you understand how the nerve impulse works.” Mindstein begins patting various pockets on his band uniform. “Ah! Here it is!” he exclaims.
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He pulls out what appears to be a short piece of dark string less than a foot long. Grabbing the ends of the string with his two hands, he pulls it taut and holds it high for the whole class to see. “Ladies and gentlemen,” he announces proudly, “The nerve impulse!” Puzzled, one of the students blurts out: “The nerve impulse is a piece of string?” “No, no!” Mindstein replies. “It’s not a piece of string, it is a fuse. Here let me show you.” He grabs a yellow clipboard, lays the fuse on the board, then holds it up at an angle. Mindstein then pulls a lighter out and touches one end of the fuse with the flame. The fuse lights and burns rapidly and brightly, leaving a long scorch mark along the clipboard. Mindstein doesn’t seem to care. “See!” Mindstein continues. “The nerve impulse!” |