L3: Membrane Potentials Flashcards Preview

Physiology I - EXAM 1 > L3: Membrane Potentials > Flashcards

Flashcards in L3: Membrane Potentials Deck (7):

Describe the permeability of cell membranes to ions under normal circumstances when at rest.

Sodium ion permeability -membrane has low permeability when at rest

Potassium ion permeability - membrane is more permeable to potassium than sodium at rest

Calcium ion permeability - membrane has a low permeability at rest

Chloride ion permeability - membrane has moderate permeability when at rest


Compare the major types of ion channels present on the cell membranes of excitable cells.

Voltage gated: changes in voltage

Ligand gated: binding of specific molecules (ligands) to receptors

Modality fated: mechanical deformation


What is the Nernst  equation and what is it used for?

E = 2.3 RT/F log Co/Ci
used to calculate membrane potential.


What is diffusion potential?

Is the potential difference generated across a membrane because of a concentration difference of an ion. Can only be generated if the membrane is permeable to the ion.


What is equilibrium potential?

Is the membrane potential where the net flow through any open channels is 0. At Erev the chemical and electrical forces are in balance.


What is electrical neutrality principle?

States that each atom in a stable substance has a charge close to zero

The sum of concentration of cations must be equal to the sum of concentration of anions


What is Donnan equilibrium?

Specifies conditions that must be met if two ions that can cross a cell membrane are simultaneously to be at equilibrium across that membrane