Psych Neuron Test

Axon

Axon

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

Dendrites

Bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body

Soma (cell body and nucleus)

The part of the neuron that contains the nucleus, the cells life-support center

Myelin sheath

The fatty tissue layer segmentally encasing the axons of some neurons; increases transmission speed and provides insulation

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons

Acetylcholine (ACh)

Enables muscle action, learning, and memory

Dopamine

Influences movement, learning, attention, and emotion

Serotonin

Affects mood, hunger, sleep, and arousal

Norepinephrine

Helps control alertness and arousal

GABA (gamma-aminobutyric acid)

A major inhibitory neurotransmitter

Glutamate

A major excitatory neurotransmitter; involved in memory

Endorphins

Neurotransmitters that influence the perception of pain or pressure

How neurotransmission works

1. A message travels from the dendrites through the cell body and to the end of the axon.

2. The message causes the chemicals, called neurotransmitters, to be released from the end of the axon into the synapse. The neurotransmitters carry the message with them into the synapse. The synapse is the space between the axon of one neuron and the dendrites of another neuron.

3. The neurotransmitters then travel across the synapse to special places on the dendrites of the next neuron, called receptors. The neurotransmitters fit into the receptors like keys in locks.

4. Once the neurotransmitter has attached to the receptors of the second neuron, the message is passed on.

5. The neurotransmitters are released from the receptors and are either broken down or go back into the axon of the first neuron.

Neuron Diagram

Polarization

The resting state of the neuron, charge is more positive outside the membrane and more negative inside

Depolarization

The action potential; the rushing in and out of positively charged ions

Repolarization

The refractory period; the closing of the membrane and reestablishing a more negative charge inside

All-or-nothing response

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

Reuptake

A neurotransmitter's reabsorption by the sending neuron