Resting potential

Definition

Resting potential refers to the electrical charge difference across a neuron's plasma membrane when it is not actively transmitting a signal. This state is typically around -70 mV and is crucial for the generation of action potentials, as it establishes the conditions necessary for neurons to respond to stimuli. The resting potential is maintained by the movement of ions, particularly sodium (Na+) and potassium (K+), through ion channels and pumps, which are essential for neuronal excitability and communication.

5 Must Know Facts For Your Next Test

1. Resting potential is primarily established by the selective permeability of the neuron's membrane to ions, especially K+ ions, which diffuse out of the cell more easily than Na+ ions can enter.
2. The sodium-potassium pump works continuously to move 3 Na+ ions out of the neuron for every 2 K+ ions it brings in, contributing to the negative charge inside the cell relative to the outside.
3. Resting potential is essential for a neuron's ability to generate action potentials; if a neuron does not reach its resting potential, it cannot effectively respond to incoming signals.
4. Changes in resting potential can occur due to various factors, including neurotransmitter activity or changes in ion concentrations, which can lead to excitatory or inhibitory postsynaptic potentials.
5. The stability of resting potential is crucial for neuronal communication, as any disruption can affect synaptic transmission and overall neural network function.

Review Questions

• How does the movement of ions contribute to establishing resting potential in neurons?
  • The movement of ions across the neuron's membrane plays a vital role in establishing resting potential. Potassium (K+) ions tend to diffuse out of the neuron due to their higher concentration inside compared to outside. At the same time, sodium (Na+) ions are less permeable and remain primarily outside. The sodium-potassium pump actively transports 3 Na+ ions out for every 2 K+ ions brought in, which helps maintain the negative charge inside relative to outside, resulting in a stable resting potential around -70 mV.
• Discuss the role of ion channels and pumps in maintaining resting potential and how their dysfunction can affect neuronal signaling.
  • Ion channels and pumps are crucial for maintaining resting potential. Specifically, the sodium-potassium pump helps establish a concentration gradient by moving Na+ out and K+ into the neuron. Ion channels allow these ions to move across the membrane selectively, contributing to resting potential. If there’s dysfunction in these channels or pumps—like a malfunctioning sodium-potassium pump—it can lead to an inability to maintain resting potential, affecting a neuron's ability to generate action potentials and communicate effectively.
• Evaluate how changes in resting potential can influence neuronal behavior and communication within neural networks.
  • Changes in resting potential can significantly influence neuronal behavior and communication within neural networks. For instance, if a neuron's resting potential becomes less negative (depolarization), it may become more excitable and more likely to fire action potentials. Conversely, hyperpolarization makes a neuron less likely to fire. These changes can affect how signals are processed and transmitted across networks, impacting everything from reflexes to complex behaviors like learning and memory. An understanding of these dynamics is essential for grasping how neurons integrate information within broader physiological contexts.

Related terms

Action potential: A rapid change in the membrane potential of a neuron that occurs when a stimulus exceeds a certain threshold, leading to the transmission of an electrical signal along the axon.

Ion channels: Proteins embedded in the cell membrane that allow specific ions to flow in and out of the neuron, playing a key role in establishing and maintaining resting potential.

Sodium-potassium pump: A protein that actively transports sodium ions out of the cell and potassium ions into the cell, helping to maintain resting potential and cellular homeostasis.