Membrane potentials Flashcards
What influence do K+ and Na+ have on RMP?
Because cells are mainly permeable to K+ ions so RMP is closest to K+ potential which is -90mV.
The potential for Na+ is +60mV. So if cell was only permeable to Na+ the RMP would be up around +60mV.
What is the resting membrane potential?
The difference in charge between the inside and outside of a cell.
The uneven distribution of these key ions establishes a potential.
The greater the separation of charges across the membrane the larger the potential.
Charge is more negative inside the cell than outside.
What is an action potential?
Nerve and muscle cells use their potentials to signal each other = action potential.
These specialised cells can transiently change their membrane potential. These changes act as electrical signals = action potentials.
How does a cell change its membrane potential?
It is triggered by a stimulus, change in voltage, chemical messenger or it happens spontaneously.
This leads to a change in ion permeability therefore alteration of membrane potential.
