NeuronUsed for communication between body partsMay be as long as a meter

Neuron partsCell body (soma)

Contains nucleusAll info collected from dendrites

DendriteBranched extensionReceives incoming signals

AxonFilament-like extension carrying signal away from

cell bodyMyelin Sheath

Fatty insulating cover surrounding axonIncreases speed and strength of signals

Now label on your diagram…AxonDendritessoma/cell bodyMyelin sheathDraw an arrow showing thedirection of impulse travel

check your understanding…What is a nerve cell called?Which part of the nerve cell RECEIVES

information?Which part of the nerve cell SENDS

information?What is like the insulation around an

electrical wire?Which part of the nerve cell contains the

nucleus?

Neurons interact with other neurons through synapsesSynapse …..junction between

two neurons. "information" flows

from one neuron to another

How do neurons communicate?

Pre-synaptic cellPost synaptic cell

Vesicle

neurotransmitter

(dendrite)(axon)

receptors synapse

Neurotransmission animation

Now label on your diagram…Presynaptic neuron (axon)Postsynaptic neuron (dendrite)SynapseVesiclesNeurotransmittersReceptorsReuptake channelsDraw an arrow showing the direction of

impulse travel

NeurotransmittersChemicals that transmit signals from a

neuron to a target cell across a synapseAcetylcholine: muscles, memoryNorepinephrine/epinephrine: fight/flightSerotonin: mood, appetite (depression)Histamine: Inflammation responseDopamine: pleasureMelatonin: sleepEndorphins: pain control

Check your understanding…What do you call the gap between two neurons?What chemicals take the signal across this gap?Name the neurotransmitter:

SleepMood, appetiteInflammation Fight or flightMuscles, memorypleasure

Steps of Neuron Communication1. Neuron at rest2. Pre-synaptic neuron fires signal3. Vesicle releases neurotransmitter4. Neurotransmitter binds to receptor on post-

synaptic neuron5. Post-synaptic neuron fires signal6. Neurotransmitters re-absorbed by pre-

synaptic neuron 7. signal has been sent

Stimulant drugs increase number of signals firedNicotineMoves through spaces between neurons

Binds to nicotine receptor on pre-synaptic neuron

Causes neuron to fire

Causes release of dopamine

If you flood your brain with nicotine, brain builds MORE nicotine receptors to suck it all up

Stimulant drugs increase number of signals firedCocaine

Present in extra-cellular space

BLOCKS reuptake channel

Synapse is flooded with dopamine

Stimulant drugs increase number of signals firedMethamphetaminePasses through membrane enters neuron

Moves into vesicle

Causes release of dopamine AND METH with signal

Also blocks reuptake channel