Which of the following explains the unidirectional propagation of action potentials?

Which of the following explains the unidirectional propagation of action potentials?

Which of the following explains the unidirectional propagation of action potentials?



  1. The voltage dependence of the sodium channels
  2. The voltage dependence of the potassium channels
  3. The presence of a refractory period at a location where an action potential has just passed
  4. Sufficient "leakiness" of the axons, such that backward propagation of action potentials is prevented
  5. The polarized orientation of microtubules within the axon

Answer: 3