Membrane Physiology

Question 1

Which are the important ions which maintain the membrane potential?

Answer 1

Na+ and K+

Question 2

Name the three types of ion channels

Answer 2

Chemical: generates Em changes at synapses
Voltage: generates action potentials
Non-gated (leak): continuous Na+/K+ flor

Question 3

What is the resting potential and how is it generated?

Answer 3

-65mV

generated by the leak channels

Question 4

Whats is the Nernst equation

Answer 4

Defines the voltage at which the forces are equal. This is done by looking at the concentration ratio

Question 5

How does the Em remain constant?

Answer 5

The driving force for Na+ is large as the permeability is so low. The driving force for K+ is small as the permeability is high. Therefore the combination of these forces ensures that Na+ movement is equal to the K+ movement.

Question 6

Why does the Em tend towards Ek?

Answer 6

more K+ leak channels are present