Resting Membrane Potential

Definition

Resting membrane potential refers to the electrical charge difference across the cell membrane of a neuron when it is not actively sending signals. This potential is typically around -70 mV, created primarily by the uneven distribution of ions, particularly sodium (Na+) and potassium (K+), across the membrane. The resting membrane potential is crucial for maintaining the neuron's readiness to generate action potentials and play a key role in synaptic transmission, allowing for effective communication between neurons.

5 Must Know Facts For Your Next Test

1. The resting membrane potential is primarily determined by the permeability of the cell membrane to different ions and the activity of ion pumps like the sodium-potassium pump.
2. At rest, the cell membrane is more permeable to potassium ions than sodium ions, leading to a net negative charge inside the neuron compared to the outside.
3. The resting membrane potential can be influenced by various factors, including changes in ion concentrations, medications, and cellular signaling.
4. Maintaining resting membrane potential is essential for the overall excitability of neurons, as it sets the stage for action potentials to occur when stimulated.
5. Disruptions in resting membrane potential can lead to neurological disorders or issues with synaptic transmission, impacting how signals are processed in the nervous system.

Review Questions

• How does resting membrane potential contribute to a neuron's ability to generate action potentials?
  • Resting membrane potential creates an electrical gradient that allows neurons to be ready for action potentials. When a neuron is at rest, it maintains a negative charge inside due to higher permeability to potassium ions compared to sodium ions. When a stimulus occurs, this potential can change rapidly, allowing sodium ions to flow into the cell and initiate an action potential. Without resting membrane potential, neurons wouldn't be able to fire signals effectively.
• Discuss how ion channels influence resting membrane potential and its role in synaptic transmission.
  • Ion channels are essential for establishing resting membrane potential by controlling ion flow across the cell membrane. At rest, potassium channels allow K+ ions to move out of the neuron while sodium channels remain mostly closed. This unequal distribution of ions helps maintain a negative charge inside the cell. During synaptic transmission, changes in these channels enable depolarization or hyperpolarization, ultimately affecting how signals are transmitted between neurons.
• Evaluate how alterations in resting membrane potential could affect neuronal communication and contribute to neurological disorders.
  • Alterations in resting membrane potential can significantly impact neuronal communication by either increasing excitability or making neurons less responsive. For instance, if resting potential becomes less negative (depolarized), neurons may fire too easily, leading to conditions like epilepsy. Conversely, hyperpolarization can inhibit signal transmission, potentially causing issues such as paralysis or muscle weakness. Understanding these changes provides insight into various neurological disorders and highlights the importance of maintaining proper ionic balance for healthy brain function.

Related terms

Action Potential:

A rapid change in membrane potential that occurs when a neuron sends a signal along its axon, typically characterized by a depolarization followed by repolarization.

Ion Channels: Proteins in the cell membrane that allow ions to enter or exit the neuron, playing a significant role in establishing and altering the resting membrane potential.

Hyperpolarization:

An increase in the membrane potential's negativity, making it less likely for a neuron to fire an action potential.