After the Exploration Expected Results When the first domino is toppled, it begins a chain reaction in which each subsequent domino is toppled until there are no more dominoes to topple. The dominoes cannot fall again until they are reset, which requires an input of human energy. In the same way, the nerve cell uses energy to redistribute ions and re-establish the resting state after a nerve impulse has propagated down the axon, and the nerve cannot fire again until this occurs. The removal of a domino from the ruler models the effects of the disease multiple sclerosis. Just as the pulse of tumbling dominoes stops when it reaches the gap in the center of the ruler, a nerve impulse stops when it reaches a portion of a neuron damaged by multiple sclerosis.
Myelin acts as an insulator similar to the nonconductive coatings of electrical wires.
The insulation provided by myelin greatly increases the rate of conduction of nerve impulses. In multiple sclerosis, the myelin sheaths are broken down, creating gaps in the myelin similar to holes in the insulation surrounding an electrical wire. These gaps interrupt the propagation of nerve impulses. The removal of a domino also mimics the effects of a severe nerve or spinal cord injury. A nerve impulse cannot propagate past the site of the injury, just as the pulse of falling dominoes is stopped by the missing domino.