Chapter 2: Synapses

Vocabulary flashcards covering key terms related to synapses and neuronal signaling.

synapse

The point of communication between two neurons.

presynaptic neuron

The neuron that sends the signal across a synapse.

postsynaptic neuron

The neuron that receives the signal at a synapse.

reflex arc

The neural pathway that mediates a reflex; transmission along a reflex arc is slower than along an equivalent length of axon due to synaptic delay.

reflexes

Automatic, involuntary responses to sensory stimuli mediated by neural circuits.

EPSP

Excitatory postsynaptic potential; a brief depolarizing graded potential produced when sodium (Na+) enters the postsynaptic neuron.

IPSP

Inhibitory postsynaptic potential; a brief hyperpolarizing graded potential produced when potassium (K+) leaves or chloride (Cl−) enters the postsynaptic neuron.

temporal summation

combines multiple signals over time, occurring when a single neuron fires repeatedly in rapid succession

spatial summation

The summation of graded potentials arriving from different locations on the neuron.

inhibition

An active brake that suppresses excitation; as important as excitation for proper nervous system function.

depolarization

A decrease in membrane negativity (less negative), often due to Na+ entry during an EPSP.

hyperpolarization

An increase in membrane negativity (more negative), often due to K+ leaving or Cl− entering during an IPSP.

graded potential

A brief, local change in membrane potential that can summate to influence whether an action potential fires.

spontaneous firing rate

The baseline firing rate of a neuron in the absence of stimulation.