A 56-year-old woman with severe muscle weakness is hospitalized. The only abnormality in her laboratory values is an elevated serum K+ concentration. The elevated serum K+ causes muscle weakness because
Elevated serum K+ concentration causes depolarization of the K+ equilibrium potential and therefore depolarization of the resting membrane potential in skeletal muscle. Sustained depolarization closes the Na+ channels and prevents the occurrence of action potentials in the muscle.
The Resting Membrane Potential Is Hyperpolarized
The K+ Equilibrium Potential Is Hyperpolarized
The Na+ Equilibrium Potential Is Hyperpolarized
Na+ channels are closed by depolarization
Excitation and Action Potiential