Excitable Cells - Resting Membrane Potential

Flashcards covering key concepts related to excitable cells, resting membrane potential, and the ionic mechanisms underlying electrical signaling.

Excitable Cells

Cells capable of generating and conducting electrical signals, important for processes like neural communication and muscle contraction.

Resting Membrane Potential (RMP)

The electrical gradient (voltage) across the membrane when an excitable cell is at rest, typically around -70 mV in neurons.

Depolarization

The process by which the membrane potential becomes more positive due to the influx of Na+ ions.

Repolarization

The process of returning the membrane potential to a negative value following depolarization, typically caused by the efflux of K+ ions.

Sodium-Potassium Pump (Na+/K+ pump)

A membrane protein that pumps Na+ out of the cell and K+ into the cell, crucial for maintaining concentration gradients and RMP.

Nernst Equation

A mathematical formula used to calculate the equilibrium potential for a specific ion across the membrane.

Action Potential

A rapid up-and-down shift in membrane potential that occurs in excitable cells when they are stimulated.

Local (graded) potential

A change in membrane potential at and nearby the point of stimulation, which can either be a depolarization or hyperpolarization.

Ion Channels

Proteins that allow specific ions to move across the plasma membrane, influencing membrane potential.

Electrophysiology

The study of the electrical properties of biological cells and tissues.

Ohm’s Law

A formula that describes the relationship between voltage (V), current (I), and resistance (R): I = V / R.

Calcium (Ca2+)

An ion that plays essential roles in muscle contraction, neurotransmitter release, and blood clotting.

Potassium (K+)

An ion primarily responsible for maintaining resting membrane potential and involved in the repolarization phase of action potentials.

Sodium (Na+)

An ion important for electrical signaling in nerves and muscles; its influx is critical in initiating action potentials.

Hyperpolarization

A change in membrane potential that makes it more negative than the RMP, typically following an action potential.