NERVE IMPULSE AND
SYNAPSES
http://www.nobelprize.org/educational/medi
cine/nerve_signaling/overview/index.html
NERVE NETWORKS
http://www.nobelprize.org/educational/medicine/nerve_s
ignaling/overview/index.html
The nervous system consists
of a complex network of nerve
cells that look like no other.
A fluorescent microscopic
image of neurons generated
from human embryonic stem
cells highlights this
complexity. Spider-like nerve
cell bodies with thin threadlike axons are visible in red
and the nuclei in blue. Yellow
neurons create and release
the neurotransmitter
dopamine, and are the type
of neurons that deteriorate in
patients with Parkinson's
disease.
Neurons conduct information in 2 ways:
1.
From one end of a neuron to the other end by electrical
impulses; these are known as action potentials.
2.
Across the minute space separating one neuron from another
by chemical transmission; through a synapse.
http://www.neusenz.com/neuron-spike-train/
http://www.sharpbrains.com/blog/200
8/06/05/your-brain-on-trading-101/
http://www.helcohi.com/sse/body/nervous.html
The Nerve Impulse
A nerve impulse is the electrical message that is
transmitted down the axon of a neuron.
Its speed ranges from approximately 1 m/s to 100 m/s.
http://five-peaks.com/nerve-impulse&page=7
http://classroom.sdmesa.edu/eschmid/Chaper9-Zoo145.htm
HOW IS THE MESSAGE SENT?
As in all cells, the cell membrane of a neuron is polarized. This means
that there is an electrical difference across the cell membrane.
SYNAPSES
Junction between two neurons.
Synaptic cleft
AXON
The synapse where the action
happens
The next cell’s plasma
membrane
Transport
protein or
pump
HOW DOES THE SYNAPSE CARRY THE SIGNAL?
1.
Nerve impulse reaches
the pre-synaptic cell.
2.
Calcium enters the
neuron
3.
Neurotransmitters are
released to the
synaptic cleft.
4. Neurotransmitter binds
the receptors in the postsynaptic cell.
5. Sodium ions enter the
postsynaptic neuron.
6. Nerve impulse along the
post-synaptic neuron.
Synapse / neurotransmitter / presynaptic neuron /Postsynaptic
Neuron / action potential
https://www.youtube.com/watch?v=xF2UFV6EKt0
Neuron Synapse
https://www.youtube.com/watch?v=LT3VKAr4roo