Lecture 2: Membrane Potentials Flashcards
Most of the bodies solutes are ___ and thus carry a ____ charge
Ions
Net Electrical
Cause ions to move across cell membranes
Gradients
Separation of ___ takes place across the membrane
Charge
The electrical potential is called the
Membrane potential
Membrane potentials are determined by 3 factors:
1. _____ of ions on the inside and outside
of the cell.
2. ____ of the cell membranes to those
ions through ion channels
3. Activity of _____ that maintain
[ion] across the membranes
Concentration
Permeability
Electrogenic pumps
All cells have different concentrations of ___ across the membrane (esp Na+, K+, Cl-), as well as ____ charged proteins to which the cell membrane is ____
Ions
Negatively
Impermeable
Typical resting potential is ___ mV
70
Resting membrane potential: Constant membrane potential in:
• ____ cells
•____ cells at rest
Nonexcitable
Excitable
Minus sign means inside of cell is ___ compared to outside
Negative
Ions responsible for generating resting potential are the cations ___ and ___, as well as____ anions.
Na+ and K+
intracellular
Na+ greater concentration in the ___, moderate permeability
• K+ higher concentration in the ___, high permeability
• A- only in the ___, no permeability
ECF
ICF
ICF
The Na+–K+ pump: __ Na+ out of the
cell for every 2___K+ in
•Inside becomes ___ compared to
outside
•Primary role of the pump is to actively
___ Na+ and K+ concentration
gradients
- 2
NEGATIVE
MAINTAIN
In a cell that is permeable to just one ion, the membrane potential that exactly opposes the concentration gradient is called the _____
or E(ion)
equilibrium potentiaL
The greater the ____ of
the plasma membrane for a
given ion, the greater the
tendency for that ion to drive
the membrane potential toward
the ion’s own ____
potential
Permeability
Equilibrium
At rest, a membrane is 50-75
times as permeable to
___, therefore ____
influences resting membrane
potential to a greater extent
Potassium
Potassium