[03] Membrane Potentials Flashcards
What is a membrane potential?
The difference in electrical charge between the inside and outside of a cell
What are the two main types of membrane potentials?
- Resting membrane potential
- Action potential
What is the resting membrane potential?
The membrane potential of a neuron when it is not being altered by excitatory or inhibitory postsynaptic potentials
What maintains the resting membrane potential?
The Na+/K+ pump
What happens during an action potential?
The membrane potential rapidly rises and falls
What is the process of an action potential?
- Depolarization
- Repolarization
- Hyperpolarization
What is depolarization?
A change in membrane potential from a negative value towards zero, causing the neuron to become excited
What is repolarization?
The process of the membrane potential returning to its resting value after a depolarization or hyperpolarization
What is hyperpolarization?
An increase in the membrane potential of a cell, relative to the normal resting potential
What is the Na+/K+ pump?
A protein that pumps sodium ions out of the cell and potassium ions into the cell
Why is the Na+/K+ pump important?
It helps maintain the resting membrane potential
What is the typical value of the resting membrane potential?
-70 mV
What causes the membrane potential to change?
The movement of ions across the cell membrane
What is the role of ion channels in the membrane potential?
They allow ions to move down their concentration gradient, which can change the membrane potential
What are voltage-gated ion channels?
Ion channels that open or close in response to changes in membrane potential
