Module 9: Biological Psychology & Neurotransmission

Neuron

Neuron

a nerve cell; the basic building block of the nervous system.

Cell body

the part of a neuron that contains the nucleus; the cell's life-support center

Dendrites

a neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body

Axon

the neuron extension that passes messages through its branches to other neurons or to muscles or glands

Myelin sheath

a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next

glial cells (glia)

Cells of the nervous system that support, regulate, and augment the functions of neurons; they also play a role in learning, thinking, and memory

terminal buttons

The branching structures at the ends of axons that release neurotransmitters

Threshold

the level of stimulation required to trigger a neural impulse

refractory period

in neural processing, a brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state

all-or-none response

a neuron's reaction of either firing (with a full-strength response) or not firing.

Synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. the tiny gap at this junction is called the synaptic gap or synaptic cleft.

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.

Reuptake

a neurotransmitter's reabsorption by the sending neuron

Acetylcholine (ACh)

A neurotransmitter that enables learning and memory and also triggers muscle contraction

Dopamine

A neurotransmitter associated with movement, attention and learning and the brain's pleasure and reward system.

Serotonin

A neurotransmitter that affects hunger, sleep, arousal, and mood.

Norepinephrine

A neurotransmitter that helps control alertness and arousal

GABA (gamma-aminobutyric acid)

A major inhibitory neurotransmitter. Undersupply linked to seizures, tremors, and insomnia.

Glutamate

A major excitatory neurotransmitter; involved in memory

Endorphins

Neurotransmitters that influence the perception of pain or pleasure

Agonist

a molecule that increases a neurotransmitter's action

Antagonist

a molecule that inhibits or blocks a neurotransmitter's action