resting membrane potential

Question 1

what is the resting membrane potential of a cell

Answer 1

the electrical potential difference across the plasma membrane when the cell is in a non-excited state

Question 2

membrane potential [Vm] is determined by

Answer 2

• distribution of ions intra and extracellularly

- variation on the membrane permeability to different ions

Question 3

the resting potential of an average neuron

Answer 3

-70mV

Question 4

diffusion potential

Answer 4

the voltage at which the electrostatic force on an ion is equal and opposite to the chemical force on the concentration gradient

Question 5

electrochemical gradient- steady state

Answer 5

• no net force, no net ion flow
• no further change in ion conc at plasma membrane
• no further change in charge distribution or membrane potential

Question 6

when Vm>Ek

Answer 6

• constant flow of ions across the plasma membrane
• Na+ moves in and K+ moves out
• the number of ions moved is very small

Question 7

role of Na+/K+ -ATPase

Answer 7

• to replenish K+ lost from the cell

- to remove Na+ accumulated within the cell

Question 8

the sodium potassium pump

Answer 8

• outer membrane of the cell
• helps maintain cells membrane potential- maintains gradient
• primary potassium pump