Chapter 12: The Nervous System and Nervous Tissue Part 2

These flashcards cover key concepts and terminology related to the nervous system and synapses as discussed in Chapter 12.

Synapse

Junctions that mediate information transfer from one neuron to another or to an effector cell.

Presynaptic neuron

Neuron conducting impulses toward the synapse, sending the information.

Postsynaptic neuron

Neuron transmitting an electrical signal away from the synapse, receiving the information.

Electrical Synapses

Less common synapses where neurons are electrically coupled, allowing rapid communication.

Chemical Synapses

Specialized for the release and reception of chemical neurotransmitters with a synaptic cleft.

Neurotransmitter

Chemical messengers that transmit signals across the synapse.

Excitatory Postsynaptic Potential (EPSP)

A graded potential that makes the neuron more likely to fire an action potential.

Inhibitory Postsynaptic Potential (IPSP)

A graded potential that makes the neuron less likely to fire an action potential.

Summation

The process through which postsynaptic potentials combine to influence neuron firing.

Temporal summation

Summation that occurs when one or more presynaptic neurons transmit impulses in rapid-fire order.

Spatial summation

Summation that occurs when multiple presynaptic neurons stimulate a postsynaptic neuron at the same time.

Neurotransmitter reuptake

The process by which neurotransmitters are reabsorbed by the presynaptic neuron.

Degradation

The breakdown of neurotransmitters by enzymes to terminate their effects.

Graded Potentials

Changes in membrane potential that vary in strength depending on the size of the stimulus.

Action Potential

A rapid rise and fall in membrane potential that occurs when a neuron sends signals.

Supramaximal stimulus

Any stimulus stronger than a maximal stimulus; it cannot produce a greater frequency of action potentials.

Neurotransmitter Acetylcholine

Controls skeletal muscle actions in the CNS and stimulates skeletal muscle contraction at the neuromuscular junction.

Dopamine

A neurotransmitter that creates a sense of well-being, with low levels associated with Parkinson’s disease.

GABA

A neurotransmitter that is generally inhibitory in the CNS.