2 Ionic Movement, Membrane Potentials & Action Potentials

Question 1

We can determine the equilibrium potential by using the _____ equation. It’s used to determine the equilibrium potential of a _____ ion. The Eq tells you what the membrane potential has to be. For sodium to stop moving across membrane, inside of cell has to go from negative to +__mV. Does it account for ALL ionic concentration gradients and permeability and you get the resting membrane potential (RMP)?

E na+= 65mv
E ca2+=120mV
E K+= -85
E Cl -90mV

Answer 1

Nernst

Single

+65mV, positive number

YES!

Question 2

What’s the charge difference across cell membranes due to concentration gradients due to concentration gradients of permeant ions? What are it’s ranges in mV?

Increasing permeability of ______to 100% would likely result in the greatest change in resting membrane potential?

Answer 2

Resting membrane potential

-20 to -100mV muscles and nerves rapidly change

Calcium

Question 3

List the steps in a neuron action potential.

At rest- ___
Local _____. Membrane moves closer to 0mV
_______ (about -60mV) point at which AP has to occur)
Overshoot. Interior becomes (+) relative to outside
________. Membrane begins to move back towards 0 and negative.
Hyperpolarization. Membrane becomes _____ negative
At rest

Answer 3

RMP
Local depolarization 
Threshold 
Repolarization 
MORE

Question 4

l, membrane conductance/open channels and the state of ionic gates
during each step.

Answer 4

Just

Question 5

Would a more or less steep repolarization slope as a consequence of acute hyperkalemia?

Answer 5

Less steep

Question 6

What would affect would hypernatremia have on the RMP?

Answer 6

None at all

Question 7

What’s the major contributor to the RMP? (Ion)

Answer 7

K+ (potassium)