Neurons Send and Receive Signals

Sodium-potassium pump

ATP-powered ion pump that maintains resting potential

Glia

Cells that provide support functions for neurons

Potassium leak channels

Channels that allow potassium to diffuse out of the cell

Voltage-gated sodium channels

Channels that open after depolarization past the threshold potential

Voltage-gated potassium channels

Channels that open during repolarization

Neurotransmitters

Chemical messengers that transmit signals between neurons

Excitatory postsynaptic potentials (EPSPs)

Depolarizations that make the postsynaptic neuron more likely to fire an action potential

Membrane potential

Electrical charge across a neuron's membrane

Nodes of Ranvier

Gaps in the myelin sheath where the signal is recharged

Inhibitory postsynaptic potentials (IPSPs)

Hyperpolarizations that make the postsynaptic neuron less likely to fire an action potential

Hyperpolarization

Increase in magnitude of the membrane charge

Myelin

Insulator that increases the speed of conduction

Synapse

Location where two neurons transmit a signal

Resting potential

Membrane potential when a neuron is not transmitting a signal

Synaptic vesicles

Membrane-bound spheres filled with neurotransmitter molecules

Action potential

Rapid, temporary change in membrane potential

Depolarization

Reduction in magnitude of the membrane charge

Axon hillock

Site where an action potential initiates within a neuron

Synaptic cleft

Small gap between two synapsed neurons

Neurons

Specialized cells that send and receive signals

Axon

Structure that transmits action potentials to the next neuron