lec 4. bioelectricity

Question 1

how to measure Vm

Answer 1

Use a sharp glass electrode to puncture the cell membrane so that the tip filled with highly concentrated salt solution and wire sits in the cell (tip is much smaller than in patch clamp). Measure Vm inside the cell with respect to a reference potential (set to 0 mV).

Question 2

Na+/K+ ATPase

Answer 2

moves 3 Na+ out and K+ in

main function is to maintain high intracellular K+ !

it also creates a negative membrane potential

inhibited by cardiac glycosides (ouabain and digoxin)

Question 3

Nernst potential

Answer 3

membrane potential of a cell if it was only permeable to one ion.

when certain channels are open, the Vm moves towards the nernst potential/equilibrium potential of that ion

= RT / XF x log [ion]o/[ion]i

Question 4

Goldman Equation

Answer 4

used to calculate theoretical membrane potential taking into account permeability of all ions in that membrane