Neurophysiology

PSP's (Postsynaptic Potentials)

Changes in the membrane potential of a postsynaptic neuron.

EPSP (Excitatory)

Makes the neuron more likely to fire an action potential.

IPSP (Inhibitory)

Makes the neuron less likely to fire an action potential.

Sodium-Potassium Pump

A protein pump in the cell membrane that active-transports sodium out and potassium in to maintain resting voltage.

Driving Forces

The combination of forces (diffusion and electrostatic pressure) that push ions across a cell membrane.

Voltage

A measure of the difference in electrical charge between two points.

Membrane Potential

The electrical voltage difference across a cell's plasma membrane.

Polarization

When a cell membrane has a clear electrical difference (positive on one side, negative on the other).

Depolarization

When the inside of a neuron becomes less negative (more positive) compared to the outside.

Repolarization

The return of a neuron's membrane potential back toward its resting negative state after depolarization.

Hyperpolarization

When the inside of the neuron becomes more negative than its normal resting potential.

Action Potential

A rapid, temporary electrical impulse that travels down an axon.

Neurotransmitter

A chemical messenger molecule released by neurons to communicate with other cells.

Receptor

A protein molecule on a cell that binds to specific neurotransmitters or hormones.

Synapse

The junction or small gap where two neurons meet to pass chemical or electrical signals.

Synaptic Cleft

The actual physical space/gap between communicating neurons.

Reflex

A fast, automatic, involuntary response to a stimulus.

Reflex Arc

The nerve pathway involved in a reflex action, usually traveling from a sensory receptor through the spinal cord straight to a motor response.