What is responsible for establishing resting membrane potential in neurons?

What is responsible for establishing resting membrane potential in neurons?

• A. The permeability of neurotransmitters
• B. The distribution of ions, primarily sodium and potassium
• C. Active transport of glucose across the membrane
• D. The amount of neurotransmitter present in the synapse

Answer: (B)

The resting membrane potential in neurons is primarily determined by the distribution of ions, particularly sodium (Na+) and potassium (K+) ions, across the cell membrane. This potential results from both the concentration gradients of these ions and the selective permeability of the neuron's membrane to various ions. At rest, the neuronal membrane is significantly more permeable to potassium ions than sodium ions. Potassium ions tend to diffuse out of the cell, driven by their concentration gradient, which ultimately makes the interior of the neuron more negatively charged compared to the outside. Meanwhile, sodium ions are less permeable and do not enter the cell as readily. In addition to the passive leakage of potassium, the sodium-potassium pump actively transports potassium back into the cell while pumping sodium out. This action not only maintains the concentration gradients of both ions but also contributes to the negative charge inside the neuron, creating the resting membrane potential, which typically hovers around -70 mV. Understanding this physiological principle is crucial, as it underlies the excitability of neurons and their ability to generate action potentials when stimulated.

The resting membrane potential in neurons is primarily determined by the distribution of ions, particularly sodium (Na+) and potassium (K+) ions, across the cell membrane. This potential results from both the concentration gradients of these ions and the selective permeability of the neuron's membrane to various ions.

At rest, the neuronal membrane is significantly more permeable to potassium ions than sodium ions. Potassium ions tend to diffuse out of the cell, driven by their concentration gradient, which ultimately makes the interior of the neuron more negatively charged compared to the outside. Meanwhile, sodium ions are less permeable and do not enter the cell as readily.

In addition to the passive leakage of potassium, the sodium-potassium pump actively transports potassium back into the cell while pumping sodium out. This action not only maintains the concentration gradients of both ions but also contributes to the negative charge inside the neuron, creating the resting membrane potential, which typically hovers around -70 mV.

Understanding this physiological principle is crucial, as it underlies the excitability of neurons and their ability to generate action potentials when stimulated.