4. Neurons & The Synapse | Quizlet

Input Zone

Dendrites collect and integrate information.

Integration Zone

The cell body makes the "decision" to produce a signal.

Conduction Zone

The axon transmits information over distances.

Output Zone

Axon terminals transfer information to other cells.

Ionic Basis of Resting Potential

The neuron's membrane is a lipid bilayer that separates ion concentrations. At rest: more K+ inside, more Na+, Cl−, and Ca2+ outside. Maintained by sodium-potassium pump and leak channels, resulting in a negative charge inside.

Graded Potentials

Neurons receive inputs that cause small, local changes in membrane potential.

Excitatory Postsynaptic Potential (EPSP)

A small depolarization that makes the neuron more likely to fire.

Inhibitory Postsynaptic Potential (IPSP)

A small hyperpolarization that makes the neuron less likely to fire.

Action Potential

If the sum of EPSPs reaches a threshold, an "all-or-none" action potential is generated. It consists of a rapid depolarization (Na+ influx) followed by repolarization (K+ efflux).

Saltatory Conduction

In myelinated axons, the action potential "jumps" between Nodes of Ranvier, speeding conduction.

Ependymal Cell

Makes and moves cerebrospinal fluid.

Astrocyte

Provides structural support and nourishment.

Microglial Cell

Acts as the brain's immune defense and clean-up crew.

Oligodendrocyte

Glial cell that myelinates multiple axons in the CNS.

Schwann Cell

Glial cell that myelinates a single axon in the PNS.

Excitatory Synapse

Makes the postsynaptic cell more likely to fire (usually uses glutamate); often located on dendritic spines.

Inhibitory Synapse

Makes the postsynaptic cell less likely to fire (usually uses GABA); often located on the cell body.

Ionotropic Receptor

Fast receptor type; directly opens ion channels.

Metabotropic Receptor

Slow receptor type; uses G-proteins and second messengers.

Neurotransmitter + Receptor

The effect at a synapse depends on both the neurotransmitter released and the receptor type on the postsynaptic cell.

Synaptic Plasticity

Synapses can get stronger or weaker with use, supporting learning and memory.

Habituation

A decrease in response with repeated stimulation.

Sensitization

An increase in response with repeated stimulation.