Lecture 3: Resting Membrane Potential Flashcards
the membrane potential is due to differences in ______ and _____ of key ions
differences in CONCENTRATION and PERMEABILITY of key ions
inside of cell is ________ charged
negatively
outside of cell is _______ charged
positively
what does the magnitude of a membrane potential depend on ?
- the # of separated opposite charges, the more # of charges, the greater the potential
- permeability of the membrane to different ions
- ions with greatest conductance contribute the most to the mp
- Na-K pump
what is the equilibrium potential for a single ion
the diffusion potential (electrical force) that exactly balances or opposes the tendency for diffusion of an ion down its concentration gradient
when is an ion in equilibrium?
when chemical and electrical forces are EQUAL & OPPOSITE
the magnitude of a potential is _______ proportional to the magnitude of concentration gradient
DIRECTLY
Na+ is greater in the ______
ECF
K+ is greater in the _____
ICF
why is it easier for K+ to cross the membrane compared to Na+?
B/c the cell has more channels that are open for passive K+ traffic than passive Na+ traffic
at resting membrane potential, the membrane is 50-75x more permeable for ____ than to _____
more permeable for K+ than Na+ at resting MP
what is the dominant ion is setting the resting membrane potential (Em)
POTASSIUM
hyperkalemia
increased ECF K+ (depolarization)
hypernatremia
increased ECF Na+ (depolarization)
hypokalemia
Decreased ECF K+ (hyperpolarization)
