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V - KCU - MSK1 (T2) - OMS1 > Resting Membrane & Action Potentials > Flashcards

Resting Membrane & Action Potentials Flashcards

1
Q

What is excitability

A

Allows cells to establish a means of communication to their own interior or other cells

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2
Q

Define RMP

A

Starting point for a cell to be potentially excited

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3
Q

What is the extracellular and intra cellular concentration and mv for K and Na

A

Na 145 (out) 12 (In) 67(mv)

K 4.5 (out) 155 (In) -95 (mv)

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4
Q

What channels most affect RMP

A

K leak channels

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5
Q

RMP is primarily due to the permeability of plasma membrane to what

A

K

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6
Q

Is the membrane permeable to Na?

A

Not so much

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7
Q

Role of ATPase in cell membrane potentials

A

Move 3 Na outside and 2 K inside cell

Does not contribute much to RMP

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8
Q

RMP of cardiac/skeletal muscle

A

-80 to -90 mv

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9
Q

RMP of smooth muscle

A

-60 mv

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10
Q

RMP of Neurons

A

-60 to -70 mv

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11
Q

Difference in diffusion and electrostatic forces

A

Diffusion is movement of chemicals down their gradients

Electrostatic is movement of charges to their opposite charges

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12
Q

RMP and K leak channels cause a build up of charges where

A

+ extracellular

- intracellular

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13
Q

Ach binds to what in muscle NMJ

A

Nicotinic Ach receptors

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14
Q

How to calc. Electrochemical forces

A

Diffusion + electrical

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15
Q

What is the equilibrium potential of Na alone

A

+66 mv

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16
Q

What is the equilibrium potential of K alone

A

-91 mv

17
Q

What is the Nernst Equation

A

E(ion) = (61.5)/Z log(xout/xin)

Z = charge of ion (+/-)

Xout = concentration of ion outside cell

Xin - concentration of ion inside cell

18
Q

How to calculate driving force

A

(RMP) - (Eion)

19
Q

What is driving force

A

How likely it is for an ion to move in or out of a cell

20
Q

What does a + DF mean

A

Efflux of ion

21
Q

What does a (-) DF mean

A

Influx of ion

22
Q

What is inside, outside and E for Cl

A 
Out = 116
In = 4.2
E = -89
23
Q

K leak channels contribute what E to RMP

A

-91 mv

24
Q

Na diffusion contributes what E to RMP

A

+5

25
Q

Na/K ATP Pump contributes what to RMP

A

-4 mv

26
Q

The more (+) RMP means what

A

The easier it is to depol.

27
Q

The more (-) RMP means what

A

The harder it is to depol.

28
Q

The resting phase is what number

A

4

29
Q

The depol phases is what numebr

A

0

30
Q

The repol phases is what numebr

A

3

31
Q

What is the main contributer to depol

A

Voltage gated Na Channels

32
Q

What do voltage gated K channels do

A

Open slowly after Na VGC close and help to repol

33
Q

What do Na VGC do

A

Open fast, allow for depol, then close quickly

34
Q

What are the phases of opening for Na VGC

Describe as well

A

Resting - activation gate is closed and inactivation gate is open

Activation - activation gate opens during intials depol

Inactivation - inactivation gate closes rapidly, can not be moved until membrane potential returns near resting

35
Q

Phases of hyperpol

A

K VGC stay open a little too long

More difficult for stimulus to make secondary AP

36
Q

What are the two refractory periods and define

A

Absolute - Na channels are either open, or the inactivation gate is closed and and not reopen (another AP cannot be generated)

Relative - inactivation gate is now open and activation gate is closed

37
Q

Steps in AP

A
  1. Rapid opening of activation gate of NA VGC
  2. Increase in membrane Na permeability
  3. Delayed closure of Na VGC
  4. Change in membrane potential initiates opening of more Na VGC

——- THE THRESHOLD IS NOW REACHED———

  1. Rapid opening of activation gate of Na VGC channels in a pos. Feedback loop
  2. Slow opening of K VGC

——-THE MEMBRANE IS NOW DEPOL——- and REPOL BEGINS

  1. Peak action is reached and membrane begins to return to normal
  2. Na VGC inactivation gates are closed
  3. K VGC are open
  4. Membrane permeability to Na decreases and K increases
  5. K VGC slowly close
38
Q

DRAW AP!

A

DRAW and lable all necessary things

V - KCU - MSK1 (T2) - OMS1 (16 decks)

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