Question

Increasing a neuron's permeability to Na+ will cause?

a) The membrane potential of the neuron to become more negative
b) An increase in the intensity of the stimulus required to generate an action potential
c) The neuron to become more hyperpolarized
d) Hyperexcitability

Answer 1

Increasing a neuron's permeability to Na+ causes the membrane to depolarize and leads to hyperexcitability by making it easier to trigger an action potential.

Step-by-step explanation:

Increasing a neuron's permeability to Na+ (sodium ions) will result in the depolarization of the neuron's membrane. This is because as Na+ ions enter the cell, they carry a positive charge, which reduces the difference in voltage between the inside and outside of the neuron. Once the threshold potential is reached, an action potential is triggered, and the neuron depolarizes, reaching a membrane potential of approximately +40 mV. This action potential is an all-or-nothing event, leading to the neuron's subsequent repolarization and return to its resting potential. Therefore, increasing neuron permeability to Na+ causes hyperexcitability, as it makes it easier for the neuron to reach threshold potential and fire an action potential.