Week 3 Flashcards
What is the resting membrane potential?
The inside of the cell is more negative than the outside.
Who is associated with the concept of resting membrane potential?
Julius Bernstein and Walter Nernst.
What occurs during neuronal stimulation?
A small decrease in membrane potential leading to depolarization or hyperpolarization.
Define depolarization.
A change in membrane potential from -70 mV to -60 mV, making it less negative.
Define hyperpolarization.
A change in membrane potential from -60 mV to -80 mV, making it more negative.
What is the role of ion channels in the cell membrane?
To protect from leakage and allow specific ions to pass through.
What happens when the threshold of around -60 mV is reached?
Na+ channels open, allowing Na+ influx into the cell.
What is the result of Na+ influx into the neuron?
The inside of the cell becomes less negative.
What is the concentration relationship of Na+ and K+ inside and outside the cell?
More Na+ outside than inside and more K+ inside than outside.
What happens to K+ channels when the threshold is reached?
K+ channels open, allowing K+ to flow out of the cell.
Fill in the blank: The Na+/K+ pump actively moves _____ out and _____ into the cell.
Na+; K+
What is the significance of the ‘all or none’ response in action potentials?
Action potentials occur when neurons are stimulated above a threshold.
What occurs during the refractory period?
Time during which a neuron cannot fire another action potential.
Describe action potential propagation.
It occurs like dominos falling.
What is the final resting membrane potential after an action potential?
-70 mV.
What is the primary function of the Na+/K+ pump?
To restore the chemical balance by pumping Na+ out and K+ into the cell.
What initiates the strong Na+ influx during an action potential?
The concentration gradient and the electrical gradient.
At what membrane potential do Na+ and K+ channels close?
Around +30 mV.
What does depolarization trigger regarding ion movement?
K+ starts to flow out driven by the concentration gradient.
What is the effect of Na+ influx on the electrical gradient?
It makes the inside of the cell less negative.
