9/30 Neuroscience: Membrane Potentials and Ion Dynamics 9/30

Vocabulary flashcards reviewing membrane equilibrium, ion dynamics, concentration and electrical gradients, and equilibrium potentials based on the lecture notes.

Ion

A charged chemical element that has lost an electron in its outer valence shell, such as sodium or potassium.

Voltmeter

A device that measures electrical potential by comparing the charge on the inside of a neuron to the outside, where the outside ground is set to $0$.

Equilibrium

A state in which the rate of ion flow into the cell is equal and opposite to the rate of ion flow out of the cell.

Equilibrium Potential

The charge that must be added to the inside of a neuron to maintain the concentration gradient of a specific ion across a membrane, assuming the membrane is permeable to that ion.

Concentration Gradient

A driving force across a membrane based on differences in ion concentration, moving ions from an area of higher concentration to lower concentration.

Electrical Gradient

A driving force across a membrane based on charge differences, where opposite charges attract and like charges repel.

Sodium ($Na$)

A positively charged ion ($+1$) that is actively pumped out of the neuron and has an equilibrium potential of approximately $+50\,mV$.

Potassium ($K$)

A positively charged ion ($+1$) that is actively pumped into the neuron and has an equilibrium potential of approximately $-80\,mV$.

Sodium-Potassium Pump

A transmembrane protein pump that uses ATP to actively transport sodium ions out of the neuron and potassium ions into the neuron.

Mitochondria

Cellular organelles that produce ATP, providing the required energy for active transport mechanisms such as the sodium-potassium pump.