resting cell membrane Flashcards Preview

ICPP > resting cell membrane > Flashcards

Flashcards in resting cell membrane Deck (7)
Loading flashcards...
1
Q

why do all cells have potential difference

A

allows cell signalling by changing the membrane potential e.g nervous system or in cells such as islets of langerhan for the release of insulin

2
Q

how to measure cell potential

A

put a negative microelectrode into the cell and run a current and will show a negative potential

3
Q

what is the range that cells charges usually are

A

-20mv to -90mv

4
Q

important cell potentials need to know

A

skeletal= -90
smooth muscle= -50
neurones= -70
cardiac= -80

5
Q

how is resting potential set up

A

in most cells k+ channels are open and k+ leaves town a conc gradient but then re-enters down a potential gradient until an equilibrium is set up and this is where the inside of the cell is negative because more anions left behind in cell

6
Q

what is the Nernst equation

A

Ek=61/z(mVlog10 [k+]0/[k+]1. this is were ek is the membrane potential if membrane selectively permeable to K+ alone. once equilibrium is reached k+ don’t move anymore and Ek doesn’t change

7
Q

what happens if you change the selective permeability of the cell

A

this is how you increase or decrease the excitability of a cell. muscle cells need a large influx for threshold value to be reached. less for neurones and smooth muscle