Transcript Neural-Ville

An Introduction to the Field of
Neuroscience
 Devise
a metaphor/imagery exercise for
neural communication.
 Sketch
and briefly explain the steps involved
in a neural impulse.
 Write
an open-ended (How/Why) question
relating to the brain/nervous system.
 This
should be the number one thing that you
want to learn during this unit.
Imagery of the Nervous System
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
Takes many small parts
and puts them together
to make one big part,
not a complete product.
Appears to be the main body
part of the Neuron.
Takes in and processes bits of
information from other
neurons.
Waits for information from
our nerves, which operate
according to our senses, etc.




Each delivers a
necessary part from
an outside source into
the factory.
Grow outward from the
cell body.
Small parts (bits of data)
travel.
The more we think, the
more plentiful dendrites
become; the more
successful our company,
the more supply routes
and supplies are needed.
 Axons
are exit-only
highways, much
larger than
dendrites.

After the Neuron has
processed the
information it has taken
in, it sends out the
processed information
to another Neuron to
help ‘complete the
puzzle’.

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
Factories rely on
other roads, just as
Neurons rely on other
Neurons’ dendrites.
The dendrites of other
Neurons wait for information
on the other side of the
synapse, just as small roads
branch out on the other side
of the river from the Axon,
but they never actually
touch.
The synapse is simply the gap
between Axon and Dendrites.
The ferries carry the
parts across the river
to the waiting roads
that will take them to
other factories;
 Neurotransmitters
carry the informative
signals across the
synapse "from the
Axon to the next
dendrites, which will
rush the information
to the other waiting
Neurons.

Neurotransmission
 You're
taking Prozac, and you've heard it
described as an SSRI. Maybe you know that
SSRI stands for selective serotonin reuptake
inhibitor. But that's quite a mouthful -- what
does it mean?
I
will give a brief, simplified description of
how the brain's message carriers
(neurotransmitters) operate, and then try to
clarify the process by telling the illustrated
story, "GABAs in the 'Hood." *
 The
monoamines - serotonin, norepinephrine
and dopamine
 GABA (gamma amino butyric acid)
 Glutamate
.

When a message comes in at
one end of a nerve cell, an
electrical impulse travels
down the "tail" of the cell,
called the axon, and causes
the release of the
appropriate
neurotransmitter.

Molecules of the
neurotransmitter are sent
into the tiny space between
nerve cells, called the
synaptic gap.
 There,
one or more of the following can
occur for each molecule:
1. It may bind (attach) to the receptors in the
adjacent nerve cell, send the message on, leave
the receptor, then repeat this process or go on to
one of the other steps.
2. It may hang around in the synapse until a
receptor becomes available, bind to it,
release, and continue with steps 1 to 3 until
its activity is ended by steps 4, 5 or 6.
3. It may bind to the first cell's autoreceptors,
which tell that cell not to release any more
of the neurotransmitter molecules, then
leave the autoreceptor and continue trying
to bind again somewhere until its activity is
ended by step 4, 5 or 6.
4. It may be rendered inactive by an enzyme.
5. It may be reabsorbed by the first cell in the
"reuptake" process, and recycled for later
use or deactivated.
6. It may diffuse out of the synapse and be
deactivated elsewhere.
 Now,
so many things can go wrong with this
process that it's not surprising mood
disorders are fairly common.
 The
nerve cells (neurons) might not be
manufacturing enough of a neurotransmitter.
 Too
many molecules of the neurotransmitter
may be dissolved or deactivated by enzymes.
 Too
much of a neurotransmitter may be
released.
 The
molecules may be reabsorbed too
quickly by the reuptake transporters.
 The
autoreceptors may be activated too
soon, shutting down the release of
neurotransmitter molecules prematurely.