Flashcards in Bioelectricity Deck (28)
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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
