CVS Practice Test

Resting membrane potential (RMP) is indeed determined by the concentrations of both positively and negatively charged ions. The RMP reflects the electrical charge difference across the cell membrane when the cell is not actively transmitting signals. It is primarily influenced by the distribution of ions such as potassium (K+), sodium (Na+), chlorine (Cl-), and negatively charged proteins within the intracellular and extracellular fluid.

The major contributors to RMP are potassium ions, which have a higher concentration inside the cell compared to outside, creating a tendency for K+ to exit the cell which contributes to a negative charge inside. Additionally, the presence of negatively charged proteins inside the cell (which do not pass through the membrane) further adds to the negative charge that helps establish and maintain the RMP.

While potassium plays a significant role, the overall influence of both positively and negatively charged ions determines the actual value of the RMP. Understanding this balance is crucial for comprehending how neurons communicate and how muscle cells contract. Therefore, indicating that RMP is influenced by both types of ions accurately captures the complexity of the processes involved in maintaining RMP.