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Caroline's raising the topic of the Myelin Sheath is very interesting to me. The analogy of the battery has mostly confused me, but it is starting to make sense to me. I think that the problem is that when I think of a bettery, I also think of electricity, and an electric pulse. Prof. Grobstein argues that we should not think of action potential in terms of electricity because electricity travels at a much higher speed than a signal through an action potential. However, I still find it helpful to combine the idea of a battery with electricity, as long as we recognize that an action potential is a slower process. This way, I can better imagine how the batteries go from one charge to another, and that activity remains during resting potential, much as electrical power is maintained even if the light bulb is not turned on.

According to this website,   http://www.miracosta.cc.ca.us/home/sfoster/neurons/mylen.htm , it seems that the definition of myelin includes the word electrical. Why is this? Should we assume that it is battery-like and electrical, or, as Prof. Grobstein argues, do not think of action potentials as electrical.

In trying to understand Myelin and speed of signal, it is interesting to look at Multiple Sclerosis, as it is (according to Wikipedia) " a chronic, inflammatory, demyelinating disease that affects the central nervous system ... Symptoms of MS, a demyelinating disease, are changes in sensation (hypoesthesia), muscle weakness, abnormal muscle spasms, or difficulty in moving; difficulties with coordination and balance (ataxia); problems in speech (dysarthria) or swallowing (dysphagia), visual problems (nystagmus, optic neuritis, or diplopia), fatigue and acute or chronic pain syndromes, bladder and bowel difficulties, cognitive impairment, or emotional symptomatology (mainly depression). and also... changes in sensation in the arms, legs or face (33%), complete or partial vision loss (optic neuritis) (16%), weakness (13%), double vision (7%), unsteadiness when walking (5%), and balance problems" -sorry for the long quotation, but I found it interesting that problems with Myelin can cause so many symptoms, and I wonder how understanding Myelin, and Multiple Sclerosis as a disease of the Myelin, can help us understand action potential, and action potential as a battery/electrical pulse, and questions of speed?