Question

Which of the following best describes what occurs when a neuron is depolarizing?

Group of answer choices
a) Sodium (NA+) leaves the inside of the cell, but Potassium (K+) enters the cell body
b) Sodium (NA+) enters the cell through sodium ion channels.
c) Potassium (K+) enters the cell through potassium channels.
d) Both Sodium (NA+) and Potassium (K+) leave the inside of the cell
.

Answer 1

During depolarization of a neuron, Sodium (Na+) enters the cell through sodium ion channels, leading to a reduction in the negative charge inside the cell and initiating an action potential.

Step-by-step explanation:

When a neuron is depolarizing, the best description of what occurs is that Sodium (Na+) enters the cell through sodium ion channels. This process begins when a nerve impulse opens the Na+ channel in the cell membrane. Due to the higher concentration of Na+ outside the cell compared to the inside, Na+ ions rush into the cell following the concentration gradient. This influx of positively charged sodium ions reduces the negative charge inside the neuron, rendering the membrane potential less negative and moving it towards a positive value, a process known as depolarization. At the peak of the action potential, potassium (K+) channels open, allowing K+ to exit the cell, contributing to the subsequent repolarization and hyperpolarization phases.