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