Electrochemistry neuro

What does resting membrane potential mean?

membrane potential in the absence of electrical signals passing through.

What is a ballpark estimate of it for most

neurons?

-65mV

If a neuron has a negative resting potential, will positive ions be electrically

pulled into or out of the cell?

drawn into the cell

Let's say a stimulus causes the membrane potential to cross spike threshold. If a greater stimulus is given, how does the response change? Does the amplitude of the action potential change?

Frequency increases but amplitude doesn't

Is an action potential an active or passive electrical response? Does it die out as it travels down the axon?

It is an active all or none response. It does not die out, the amplitude remains the same.

What does electrochemical equilibrium mean for an ion?

the movement of ions due to the electrical force in one direction is exactly canceled out by the diffusion down the concentration gradient in the opposite direction. When this balance is reached, there is no net diffusion of the ion across the membrane.

electrochemical equilibrium 2 factors?

diffusion down the concentration gradient and electrical force

Does it mean that that ion stops crossing the membrane completely (electrochemical equilibrium)?

No, the two factors influencing ion movement are perfectly balanced

What is the equilibrium potential of an ion?

the membrane potential at electrochemical equilibrium.

Is Na+ concentration outside the neuron greater, lesser or equal to that inside the neurons?

greater

Is K+ concentration outside the neuron greater, lesser or equal to that inside the neurons?

lesser

Is Ca2+ concentration outside the neuron greater, lesser or equal to that inside the neurons?

greater

Active transporters

responsible for establishing and maintaining the crucial ionic concentration gradients inside and outside of the neuron. These concentration differences provide the energy that drives ionic currents.

Ion channels

proteins that provide specific passageways through the cell membrane for ions. They are integral to generating the rapid electrical signals used by neurons.

Is the equilibrium potential of K+ positive or negative?

negative

Is the equilibrium potential of Na+ positive or negative?

positive

At resting potential, the membrane is most permeable to which ion?

Potassium K+

Starting at resting potential, if the membrane were made more permeable to K+, would the membrane potential move towards or away from the equilibrium potential of K+?

It would move towards the equilibrium potential for K+

At the peak of an action potential, the membrane is most permeable to which ion?

It is more permeable to Na+

If you changed the outside concentration of Na+, would the equilibrium potential of Na+ change?

yes, it would change

If you changed the outside concentration of K+, would the equilibrium potential of K+ change?

no, it would not change