L3: Cell Membrane Electrophysiology Flashcards
What is the cell membrane a barrier to?
Cell membrane is a barrier to free moving ions
What are transport proteins for?
Transport proteins facilitate and regulate the movement of ions
What is the Nernst equation used for?
Nernst equation calculates the potential energy of a chemical gradient
Is there a driving force when at equilibrium?
Equilibrium when chemical potential and electrical potential are equal → no net movement of ions
What is the equilibrium potential?
Equilibrium potential = the membrane potential if one ion had control → Chemical and electrical gradients for that ion would be equal
What 2 factors affect permeability?
- how many channels are in the membrane
- how many channels are open
Why is the RMP primarily due to K+ current?
cell membrane much more permeable to K+ => RMP primarily due to K+ current, made slightly more positive by Na+ current
What enzyme maintains ion gradients?
Na/K ATPase maintains gradients, uses ATP to pump ions against their conc. gradient
Describe local potentials (3)
= channel openings that cause changes in membrane potential
= graded in size
= summate in time and space
Define overshoot
Anything that causes membrane potential > 0
Define depolarisation
anything that makes the membrane potential more positive
define repolarisation
becoming more negative (but still above RMP)
define hyperpolarisation
more negative than RMP
