4 Written Questions

1. Cl- re-enters, as do K+ and water, to restore normality. Value falls to -110 mV.
2. Membrane stability. It allows the membrane potential to return to normal.
3. Em sets the Cl- gradient rather than the Cl- gradient setting Em (like K+)
4. True.

4 Multiple Choice Questions

1. True
   1. Phase 4
   2. Phase 5
   3. High permeability of Cl-
   4. Phase 6
2. Normal Em for a frog skeletal muscle. Value = -100mV
   1. Phase 1
   2. Phase 5
   3. Phase 3
   4. Phase 4
3. Congenital reduction in pCl- produces spontaneous firing and contaction of muscle. MYOTONIA
   1. What advantage does high pCl- have
   2. What porblems could arise with altered pCl-
   3. High permeability of Cl-
   4. Connection Between Em and Cl-
4. Cl- efflux depolarizes cell (makes it less negative). K+ efflux due to depolarization. Value= -75mV
   1. Phase 5
   2. Phase 1
   3. Phase 4
   4. Phase 2

3 True/False Question

1. Phase 3 → Em returns to normal value after 16mins. K+ gradient is restored
   

   True        False

2. Phase 6 → Cl- re-enters, as do K+ and water, to restore normality. Value falls to -110 mV.
   

   True        False

3. Phase 4 → KCl leaves cell, so water foloows osmotically.
   

   True        False