Which of the following statements about the refractory period of neuronal or muscle membranes is TRUE?
A. In nerve cells, the absolute refractory period coincides with the period of increased K+ permeability.
B. In skeletal muscle cells, the absolute refractory period lasts about as long as the twitch.
C. The relative refractory period in neuronal membranes lasts about the same length of time as the absolute refractory period in cardiac muscle cell membranes.
D. The refractory period in an alpha-motor neuron membrane is much briefer than the refractory period in a skeletal muscle cell membrane.
E. In ventricular cells, the absolute refractory period coincides with the period of increased Na+ and Ca2+ permeability.
Answer: E
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