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Unformatted text preview: Neural Neural Communication Basic Terminology – Neuronal Parts
Basic Terminology – Neuronal Parts Neuron – basic building block of the nervous
Dendrite – part of neuron that receives
messages from other cells and passes the
messages to the cell body
Cell Body – control center of neuron, contains
Axon – sends messages to other neurons,
glands, muscles, etc
Cont. Myelin Sheath – fatty tissue covering some
axons, speeds conduction of neural impulse
Synapse – Junction between axon of one
neuron and dendrite of another
Receptor – protein that binds
neurotransmitters, hormones, or drugs
neurotransmitters, Basic Terminology – Neural Basic Terminology – Neural Communication Action potential – brief electrical charge that
travels down an axon. Caused by positively
charged ions moving in and out of channels on
the axon’s membrane.
Threshold – the level of stimulation required
to trigger an action potential. Threshold is
reached through depolarization.
Cont. Depolarization – When the inside of an axon
becomes more positive through an inward flow
Hyperpolarization – Return of the inside of the
axon to a more negative charge.
Cont. All-or-none – Action potentials can’t be
partial, they either happen or they don’t.
Refractory period – the period in which a new
action potential can’t occur Neurotransmitters
- - Chemical messengers that traverse the
synaptic gaps between neurons and bind to
Dopamine – movement, learning, attention,
emotion, reward (linked with schizophrenia,
- - - - Serotonin – mood, hunger, sleep, arousal
(linked with depression)
Norepinephrine – alertness and arousal (linked
Endorphins – natural opiate-like transmitters
linked to pain control and pleasure
50-60 types of known neurotransmitters Sequence of Events
Sequence of Events
1. 2. 3.
4. Dendrite receives messages in the form of
Through temporal and spatial summation,
message is passed to cell body.
Depolarization of cell body begins.
If depolarization is sufficient to reach
threshold, action potential occurs.
2. 3. 4. Action potential travels down axon.
At the synapse, action potential is converted
to neurotransmitter which is released into
NT binds to receptors on dendrites of next
neuron (Process starts over in new neuron) .
Hyperpolarization occurs in original neuron
and refractory period is entered.
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- Spring '08