L3: Membrane Potentials Flashcards Preview

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

Flashcards in L3: Membrane Potentials Deck (7):
1

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

2

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

3

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

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

4

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.

5

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.

6

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

7

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