Neurobiology 2: Electrochemical Gradient and Resting Potential

Flashcards covering key concepts related to the electrochemical gradient, resting membrane potential, ion movement, and ion channel functions in neurobiology.

What is an ion?

A molecule with a net electrical charge.

Which ions are most important for an action potential?

Potassium (K+), Sodium (Na+), and Chloride (Cl-).

What causes an electrical gradient across a membrane?

A difference in electrical charge across the membrane.

What drives the chemical gradient?

The relative concentration of ions.

What two gradients together form the electrochemical gradient?

The electric gradient and the chemical gradient.

What type of energy is created by the electrochemical gradient?

Potential energy, also referred to as 'pent up' energy.

What is the potential energy resulting from the electrochemical gradient called in an axon?

The RESTING MEMBRANE POTENTIAL.

What is the typical resting membrane potential of a neuron?

-70 mV.

What instrument is used to measure the potential (charge) difference across the membrane of a resting cell?

A voltmeter.

How is the cytoplasmic side of a resting membrane charged relative to the outside?

Negatively charged.

Where is the concentration of Na+ higher in a resting neuron?

Outside the neuron.

Where is the concentration of K+ higher in a resting neuron?

Inside the neuron.

What are the two main types of ion channels found in membranes?

Leakage (nongated) channels and Gated channels.

How do chemically gated (ligand-gated) channels open?

Only with the binding of a specific chemical, such as a neurotransmitter.

How do voltage-gated channels open and close?

In response to changes in membrane potential.

Why is the inside of the cell negative at resting potential, considering leakage channels?

More K+ leaks out of the cell than Na+ moves into the cell, due to higher permeability to K+ and the impermeability of large anionic proteins.

What is the function of the Na+-K+ pump in maintaining the resting membrane potential?

It stabilizes the resting membrane potential by actively pumping 3 Na+ ions out of the cell and 2 K+ ions into the cell, maintaining concentration gradients.