What ion concentrations primarily create resting membrane potential?

The concentration of ions across the neuronal membrane plays a crucial role in establishing the resting membrane potential, which is typically around -70 mV in neurons. The primary ions involved in generating this potential are potassium (K+), sodium (Na+), and chloride (Cl-).

Potassium ions are fundamental in setting the resting membrane potential because the neuronal membrane is highly permeable to K+ at rest. Due to the concentration gradient, potassium tends to move out of the cell, causing a negative charge inside relative to the outside.

Sodium ions also influence the resting membrane potential, although to a lesser extent than potassium. The membrane is less permeable to Na+ at rest, but the significant concentration gradient exists, with a high concentration of Na+ outside the cell and a lower concentration inside. If Na+ were to enter the cell, it could depolarize the membrane, highlighting its role in the overall ionic balance.

Chloride ions contribute to the resting membrane potential as well, although their role can be more variable depending on the type of neuron and its specific membrane properties. Generally, an outward flow of Cl- can help maintain the necessary balance to stabilize the negative potential.

In summary, the electrical potential across the membrane is largely dictated by