The resting membrane potential in contractile cells of the atria and ventricles is about -70mV
The inside of the cell is positively charged in relation to the outside of the cell
The resting membrane potential is primarily due to two
things; the high concentration of potassium ions in the intracellular fluid and the high permeability of the cell membrane K+ ions as compared to other ions
The resting membrane potential is close to the equilibrium potential for sodium
Which of the following are the events of phase 0 - upstroke
Respuesta
Potential reaches threshold: –65 mV
Membrane’s ionic permeability suddenly changes
Cell rapidly depolarises and over shoots to a positive potential of +40mV
At the threshold potential, voltage sensitive potassium channels open very quickly
Pregunta 6
Pregunta
The membrane potential does not reach the equilibrium potential of sodium because the outward [blank_start]potassium[blank_end] current is still flowing
Respuesta
potassium
Pregunta 7
Pregunta
In early repolarisation why is the overshoot brief?
Respuesta
Fast sodium channels that are self inactivating decreases conductance of sodium
Fast potassium channels that are self inactivating decrease conductance of potassium
Voltage sensitive sodium channels quickly close
Voltage sensitive potassium channels quickly close
Pregunta 8
Pregunta
Within a couple of milliseconds the membrane voltage repolarises a few mV, owing to an outward current of