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Questions and Answers
What is the resting membrane potential in neurons?
-70 mV
Which forces contribute to membrane potential?
The concentration gradient drives molecules from low to high concentration.
False
What is the main ion that has a positive electrical gradient forcing it into the neuron?
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How many potassium ions are pumped into the cell by the Na+/K+ pump?
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What helps establish the resting membrane potential?
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Study Notes
Membrane Potentials
- At rest, axons are not propagating action potentials but maintain a resting membrane potential.
- Resting membrane potential is influenced by concentration gradients and electrical gradients of ions in intracellular and extracellular spaces.
Concentration and Electrical Gradients
- Diffusion force drives ions from areas of high concentration to low concentration.
- Electrical force drives ions from areas of high positive (+ve) charge to low negative (-ve) charge.
- Equilibrium potential occurs when electrical and concentration forces equalize, typically at -70mV in neurons.
Ion Concentration Gradients
- Major ions involved include Na+, K+, Ca2+, Cl-, and negatively charged proteins (OA-) in both intracellular and extracellular spaces.
- Na+ has a positive electrical and concentration gradient pushing it into the neuron, despite lower permeability through leak channels.
- K+ is more permeable due to a higher abundance of K+ leak channels, establishing the -70mV resting potential.
Na+/K+ Pump Mechanism
- The Na+/K+ pump transports 2 K+ ions into the cell and 3 Na+ ions out of the cell through active transport.
- This process requires energy in the form of ATP and moves ions against their concentration gradients.
Influence of Leak Channels
- K+ leak channels are more numerous than Na+ leak channels, resulting in greater resting permeability to K+.
- This differential permeability contributes significantly to the maintenance of the resting membrane potential.
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Description
Explore the foundational concepts of resting membrane potential as related to brain and behavior. This quiz will cover key processes, including concentration gradients and ionic charges, as axons maintain a resting state. Test your knowledge on the crucial aspects that influence neuronal activity.
