1. Why are pseudounipolar neurons not called "unipolar" neurons? What advantage might a sensory neuron gain by being pseudounipolar instead of bipolar or multipolar?

2. Can all peripheral neurons be said to have a sheath of Schwann--even those that do not have a myelin sheath? What advantage does a sheath of Schwann bestow that is lacking in the CNS?

3. Why is it important, in the production of an action potential, that the voltage-regulated Na⁺ and K⁺ gates open at different times? What might happen if they should both open at the same time?

4. Considering the physiological function of a myelin sheath, how would diseases of the myelin, such as multiple sclerosis or Tay-Sach’s disease, affect nerve function?

5. People with the disease myasthenia gravis produce antibodies that block their ACh receptors. How do you suppose this affects their ability to contract muscles? How can such people be helped by drugs that block acetylcholinesterase?

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