What effect does hyperkalemia have on a resting cell's potential?

Hyperkalemia refers to an elevated level of potassium in the bloodstream, which has a significant impact on the resting membrane potential of cells, particularly in excitable tissues like neurons and muscle cells. Normally, the resting membrane potential is governed by the distribution of ions across the cell membrane, with a high concentration of potassium ions inside the cell and a higher concentration of sodium ions outside.

When potassium levels in the extracellular environment increase, this alters the concentration gradient. Normally, potassium ions flow out of the cell through potassium channels, contributing to the negative resting potential. However, with hyperkalemia, the gradient for potassium decreases, meaning there is less driving force for potassium to leave the cell. As a result, the inside of the cell becomes less negative compared to the exterior, leading to depolarization.

Depolarization is characterized by a shift in the membrane potential towards a less negative value, which can make it easier for the cell to reach the threshold for firing an action potential. This effect is crucial for understanding how hyperkalemia can influence cardiac and neurological function, as it can lead to increased excitability or arrhythmias in heart tissue.

In summary, hyperkalemia causes depolarization of a resting cell's potential, which can impact physiological functions