The most important physiological effect of the absolute refractory period is tha
ID: 190246 • Letter: T
Question
The most important physiological effect of the absolute refractory period is that it:
A. it provides sufficient time for closing of voltage-gated calcium channels
B. prevents leak potassium channels from closing too early after the action potential
C. insures that action potentials are conducted in one direction, from axon hillock to axon terminal
D. it provides sufficient time for opening of voltage-gated potassium channels.
According to the model of voltage-gated sodium channels, there is no current through the channel when it's inactivated because __________________
A. a globular part of the channel is blocking the pore.
B. the pore of the channel is closed.
C. the concentration of sodium ions inside the cell has increased and this prevents more sodium ions from entering.
D. A and B are both correct
E. A, B and C are all correct
Explanation / Answer
1) Insures that action potentials are conducted in one direction, from axon hillock to axon terminal - Absolute refractory period is important in unidirectional propagation of action potentials and sodium inactivation closes the sodium channels temporarily so they do not open in response to reductions in membrane potential.