neurons: resting membrane potential

Question 1

resting membrane potential

Answer 1

inside of the cell is more negative at rest
only in muscle and neurons and muscle fibres can respond suddenly to transient change of potential due to voltage gated ion channels

Question 2

how is RMP generated

Answer 2

inside of cell is more negative due to
1) unequal concentrations: Na+ and K+ is unequal on either side so electrochemical gradient
2) unequal permeability: ie less permeable to sodium and more permeable to potassium

Question 3

cellular concentrations of Na+ and K+

Answer 3

Na+: higher outside of cell
K+: higher inside of cell
Na/K pump: 3 Na out and 2 K

Question 4

how intracellular potentials measures

Answer 4

1) micro electrode recording
2) patch clamp technique

Question 5

nernst equation - equilibrium potential

Answer 5

potassium: Eion = 61.5 mV x log [ion]o/[ion]i
will be really negative -80mV
sodium will be around +60mV

Question 6

goldman equation

Answer 6

A way of calculating the value of the RMP taking into account both the concentration
gradients AND the relative permeability of the resting cell membrane to K+ and Na+ ions

Question 7

channels

Answer 7

1) non-gated leak channels - open at rest, allows diffusion of ions
2) gated (voltage, ligand, mechanical) - closed at rest

Question 8

permeability of K and Na

Answer 8

at rest: PK/PNa ≈ 40/1
due to leak channels being more prevalent for K