Bioelectricity Flashcards Preview

BMS 242 Core Physiology and Pharmacology > Bioelectricity > Flashcards

Flashcards in Bioelectricity Deck (28)
Loading flashcards...
1

What is membrane potential critical for

cell function

2

True or False - ALL cells have membrane potentials

TRUE

3

How do you measure membrane potential

Impail the cm into the intracellular fluid compartment with glass electrode, measure in respect to 0mV fluid

4

What determines membrane potential

unequal distribution and selective movement of ions

5

What does Vm stand for

membrane potential

6

What transporter maintains normal cell membrane potential / environment

Sodium potassium ATPase

7

What is the contribution of the sodium potassium ATPase to the resting membrane potential

contributes 20% directly

8

How does sodium potassium ATPase contribute to the resting membrane potential.

Na+/K+ ATPase carries one positive charge out of the cell

9

What is the effect of the Na+/K+ ATPase carrying one positive charge out of the cell

leaves a negative charge inside the cell, this maintains the driving force

10

Describe the concentration gradient for potassium movement in relation to the cell

concentration gradient for potassium to move out of the cell

11

What is the effect of potassium moving out of the cell

inside of the cell becomes more negative

12

What ions cannot cross the cell membrane

anions

13

Why is it important that anions cannot cross the cell membrane

allows cell to generate negative membrane potential

14

What is the current when there is no NET movement of potassium

0 current

15

What is the potential called when there is no NET movement

Nernst potential

16

What is the effect of ion movement on membrane potential

move the membrane potential towards their Nernst potential

17

What does it mean if a cells membrane potential is -70mV

potassium channels are working and functional

18

Why is the cells membrane potential slightly more positive than the Nernst potential for potassium

Sodium channels can be slightly leaky

19

Describe the concentration gradient for sodium movement

sodium moves into the cell down its conc gradient

20

What is the effect of sodium influx on the cell potential

makes the membrane potential more positive

21

What is the Nernst potential for sodium

+61.5

22

What is the effect of sodium channels opening on the membrane potential

shift the membrane potential towards the Nernst potential for sodium

23

What does the Goldman equation calculate

Membrane potential

24

What does the Goldman equation give us information about

membrane permeability

25

What would the cells membrane potential be if only sodium channels were open

+60mV

26

Why does the influx of sodium generate an action potential

when voltage gated sodium channels open the influx of sodium drives the membrane potential towards its Nernst potential - positive

27

Describe the repolarisation phase of the action potential with reference to potassium and their Nernst potential

at the peak of the action potential, potassium channels open and drive the membrane potential towards its Nernst potential - negative

28

What is different about Na+ amino acid co transport in the epithelial cell with reference to the membrane potential

Repolarisation occurs when potassium channels open however this is more gradual and the co transporter remains open