lecture 3 notes

Na/K ATPase

Enzyme that moves Na and K across the membrane to establish and maintain normal ECF and ICF concentrations.

Equilibrium potential of potassium

The point at which the outward movement of K is exactly matched by the inward movement of K.

Resting membrane potential (RMP)

The voltage difference across the membrane when the cell is at rest, close to E_k.

Leaky K channels

Channels in nerve cells that allow K to move out, contributing to the negative charge inside the cell.

Electrochemical equilibrium

The state at which chemical and electrostatic forces on an ion balance each other.

Local potential

The triggered change in membrane potential that may initiate action potentials.

Permeability properties

Characteristics of the membrane that determine the ease with which ions can cross it.

Chemical gradient

The difference in ion concentration across the membrane that drives ions to move.

Electrostatic attraction

The force that pulls K back into the cell due to the negative charge inside the cell.

Relative permeability to K and Na

The resting membrane is 50-100x more permeable to K than to Na.