Lipid Bilayer

The ability of cell membranes to allow certain substances to enter and exit the cell while blocking other substances. The blockage of other ions is enabled by a selectivity filter inside ion channels like the potassium (K+) ion channel, which contains oxygen atoms in its interior that easily escort K+ ions but have difficulty escorting other ions. 

Selective Permeability

Separates the inside of the cell from its environment using a lipid bilayer.

California Polytechnic State University, San Luis Obispo

An ion is a molecule that carries an electrical charge. In the context of a neuron, ions are dissolved in both the intracellular and extracellular fluids, and their unequal distribution across the semipermeable membrane is the source of the electrical charge that constitutes the membrane potential.

Ions

Breedlove, S. & Watson, N. (2017). Behavioral neuroscience, eighth edition. Oxford University Press.

Behavioral Neuroscience 8th Edition

A negatively charged ion. Most of the ions in a resting neuron are anions.

Anion

Cation

Cell Membrane

Voltage Gated 

Ligand Gated

Mechanically Gated 

pH dependent 

Temperature dependent

Leak channels

Ion Channel Types

The membrane potential is the difference in electrical charge between the intracellular and extracellular fluids across the neuronal membrane. This electrical difference serves as the energy source for the neural signal.

Membrane Potential

A neuron's membrane separates an internal fluid from an external fluid. If a large number of positively charged ions are suddenly allowed to move from the external fluid to the internal fluid, how would this movement affect the electrical charge inside the neuron relative to the outside?

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