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MSS - MSK Exam 2 > Membrane Electrophysiology: RMP > Flashcards

Membrane Electrophysiology: RMP Flashcards

1
Q

membrane potential

A

separation of charge across plasma membrane

potential to do work

in millivolts

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2
Q

resting membrane potential

A

when not sending electrical signals (equilibrium)
-no net ion flow

expressed as intracellular potential relative to extracellular potential

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3
Q

intracellular anions

A

fixed, so cations balance the charge

impermeable molecules (proteins)

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4
Q

Na+ K+ Pump

A

electrogenic
ATP dependent ion pump
indirect contribution to RMP maintaining ion [gradient]

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5
Q

what ions have great contribution to RMP?

A

those with greatest permeability

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6
Q

Exchange rate for Na/K pump

A

3 Na out and 2 K in

positive outside
more sodium outside/potassium inside

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7
Q

distribution of Na?

A

greater in ECF

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8
Q

distribution of K?

A

greater in ICF

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9
Q

electrogenic

A

sodium/potassium pump that causes a net movement of +1 outside of cell

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10
Q

diffusion potential

A

due to concentration difference of an ion

-contributes to RMP

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11
Q

distribution of calcium

A

much more outside cell ECF

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12
Q

distribution of chloride

A

more outside ECF

-larger concentration difference in skeletal muscles

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13
Q

force acting on an ion?

A
  1. concentration (chemical) force
  2. electrical force

NET force is sum of two

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14
Q

electrical force

A

depends on membrane potentital and charge on particle

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15
Q

equilibrium potential

A

unique for each ion

-when chemical and electrical gradients balance out

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16
Q

nernst equation

A

to predict equilibrium potential for any concentration gradient of an ion

Ex=60/z log10 (Xo/Xi)

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17
Q

log10 (10) = ?

A

1

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18
Q

log10 (0.1) = ?

A

-1

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19
Q

net force on ion?

A

difference between Ex and Vm

20
Q

potassium equilibrium potential?

A

-90mV

21
Q

sodium equilibrium potential?

A

+60mV

22
Q

driving force

A

Vm - Ex

23
Q

if Vm is more negative?

A

inward current of cations

24
Q

if Vm is more positive?

A

outward current of cations

25
Q

which ion has greatest driving force?

A

calcium

26
Q

at RMP what ways would major ions move?

A

potassium out
sodium in
calcium in
chloride in

27
Q

what determines membrane conductance?

A

number of open channels

-channels are opening, conductance is increasing

28
Q

rate of ion movement depends on?

A

external and internal concentrations of ions
transmembrane voltage
permeability of ion

29
Q

ungated ion channels

A

leak channels

always open

30
Q

voltage gated channels

A

open/close in response to membrane voltage change

31
Q

ligand gated channels

A

open/close in response to binding ligand

32
Q

potassium contribution to RMP?

A

high K+ inside cell
2 opposing forces - chemical vs electrical
K+ not at EQ

ungated, leak channels always open

NET EFFLUX OF K+

33
Q

increased K+ conductance?

A

hyperpolarization

34
Q

decreased ECF potassium?

A

hyperpolarization

35
Q

increased ECF potassium?

A

depolarization

36
Q

RMP and K?

A

very sensitive in change to ECF concentration of potassium

37
Q

reversal potential

A

voltage at which current direction is reversed

nernst potential of ion

38
Q

major determinant of RMP?

A

potassium

39
Q

diffusion of K+

A

concentration - OUT

electrical - INSIDE

40
Q

RMP and Na?

A

high sodium outside cell

low permeability to Na+

large force on sodium (far from EQ)

41
Q

is resting membrane potential sensitive to changes in sodium?

A

NO

42
Q

increase or decrease in ECF sodium?

A

minimal effect on RMP

43
Q

sodium concentration gradient

A

INSIDE cell

44
Q

sodium electrical gradient

A

INSIDE cell

45
Q

skeletal muscle, cardiac, and nerve cell RMPs?

A

-60 to -90mV

46
Q

Na/K pump

A

continues to restore gradient by pumping K+ back in

MSS - MSK Exam 2 (13 decks)

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