Briefly describe the role of Cl channels in skeletal muscle action potential

Depolarisation phase (excitation) - Na+ and Ca2+ channels open, letting Na +and Ca2+ ions into the cell Repolarisation phase (recovery from excitation) – K+ and Cl-open, letting K+ ions out and Cl-ions into the cell Skeletal muscle cells have high Cl conductance due to a large number f Cl channels on the plasma membrane ( 80% of total membrane conductance at rest) Increased excitability of the muscle can be caused by an increase in Na+ and/or Ca2+ conductance, or by a decrease in K+ and/or Cl-conductance Myotonia can be induced by blocking Cl-conductance by at least 60-70%