Problem:

Question 1: How do absolute the relative and absolute refractory periods differ from each other? Describe these differences in terms of channels, their gates and ion permeabilities.

Question 2: A dentist will inject the anesthetic lidocaine into the trigeminal nerve to alleviate the sensation of pain in the jaw. However, a side effect of this injection may be the inability to use the anterior two-thirds of the tongue and lower lip properly, resulting in slurred speech and drooling. Explain the mechanism of action of the anesthetic on the nerve, why the pain sensation is alleviated and the side effects.

Question 3: You have learned that action potentials are all-or-none phenomena. Since all action potential are alike, how does the brain discriminate between stimuli that require immediate attention (a strong stimulus) and ordinary baseline/positional stimuli?

Question 4: Multiple sclerosis (MS) is an autoimmune disease of the CNS in which the myelin sheaths are destroyed. What process does this interfere with and what would be the consequence?

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