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Nervous System
Nir Liebenthal, Alex Lee, Sabrina Smith
What is the Nervous System?
The Nervous System is the network of nerve
cells and fibers that transmits nerve impulses
between parts of the body. The nervous
system receives information about conditions
both within and around the body. It processes
and integrates this information on a variety of
levels, and directs the body to respond
appropriately (1, 4).
Neurons
Neurons are interacting
cells that work together
to monitor the
conditions in and
around the body.
Neurons issue
responsive actions that
help the body as a
whole.
Function: They interact as
the communication
lines of the brain, spinal
Athletics Wiki. Athletepedia, n.d. Web. 2 Nov. 2012.
<http://athletics.wikia.com/wiki/Nervous_System>.
Neuron Structure
All neurons have three common features:
1. The cell body (Soma): contains the nucleus and
other organelles essential for the survival of the
neuron. It is usually small compared to the rest of
the neuron.
2. One or more dendrites extend from the cell body.
The dendrites serve to receive incoming electrical
signals from other neurons.
3. Most neurons have a single axon to transmit
outgoing signals. Axons vary in length from
micrometers to over a meter. Portions of the axon
are insulated by supporting cells with myelin, a
phospholipid membrane (3).
http://www.bumpybrains.c
om/uNeurons.html
Myelin Sheath
Form: The Myelin Sheath is made up of
Schwann cells (a type of neurological cell)
in the peripheral nervous system..
Function: The Myelin Sheath is the
insulating envelope of myelin that
surrounds the axon. It prevents the
electrical current from leaving the axon
and facilitates the transmission of nerve
impulses by speeding up conduction (4).
Analogy: the Myelin Sheath is like the rubber
coating around a wire that prevents
electricity from leaving the track of the
http://www.empowher.com/files/ebsco/i
mages/AX00010_97870_1_myelin_sh
eath.jpeg
Ions and Action Potential
The two major ions are sodium (Na+) and potassium (K+).
Sodium diffuses out of the neuron, and Potassium
diffuses into the neuron.The two ions cross the
membrane through channel proteins (3).
Some channel proteins never shut, so the ions diffuse
through them all the time. Other channel proteins act
like flood gates, that open only after a neuron is
stimulated.
Sodium-potassium pumps (active transport proteins)
restore the neuron to resting potential (2).
Ions and Action Potential Cont.
At resting potential, there are many more sodium ions on the outside, so the neuron is negatively charged
relative to its external environment. The voltage difference at rest is -70mV.
An action potential occurs when a neuron sends information down an axon, away from the cell body (a
stimulus). When this happens...
1. Sodium gates open and the neuron
becomes depolarized.
2. Potassium gates open while sodium gates
close, and potassium rushes out of the cell
causing the action potential to go back
toward -70 mV (repolarization)
3. However, the action potential actually
goes past -70 mV (hyperpolarization)
because the potassium channels stay
open a bit too long.
4. Sodium-potassium pumps, bring the
neuron back to resting potential by
pumping sodium out of the neuron and
potassium back in. The sodium gates stay
closed, so the sodium that is pumped out
stays out until the next active potential (2).
http://faculty.washington.edu/chudler/ap.html
Poem
The Nervous System is really cool
Don’t drop out of school
But thats not the reason of the presentation
We want to teach the Nervous System to an entire nation
The nervous system transmits nerve impulses between body parts
if you understand that, you can get a bachelor in arts
Neurons are interacting cells that work together
they will monitor the conditions of your body forever
They are communication lines between the nerves, spinal cord, and brain
If they didn’t work, our body would have mega pain
Neurons are made of the Soma, Dendrite, and Axon
If you don’t know that, get it together man (mon)
The Myelin Sheath is something you should know
It is the insulating envelo....pe
It is like the rubber coating around a wire
If you want insulation the myelin sheath is who you should hire
Ions and action potential, is that ever confusing
But listen to this, and then you’ll be cruising
It’s the change in electrical potential of an impulse of a muscle cell or nerve cell
See? not that bad, and at least it doesn’t smell
The Nervous system is pretty cool
I hope you enjoyed this poem
that didn’t rhyme
but I didn’t have any more time
Bibliography
1. Athletics Wiki. Athletepedia, n.d. Web. 2 Nov. 2012.
<http://athletics.wikia.com/wiki/
Nervous_System>.
2. Chudler, Eric H. "Lights, Camera, Action Potential." Neuroscience For Kids.
Eric H. Chudler, n.d.
Web. 6 Nov. 2012. <http://faculty.washington.edu/chudler/ap.html>.
3. The Nervous System. N.p., n.d. Web. 6 Nov. 2012.
<http://mcb.berkeley.edu/courses/mcb135e/
nervous.html>.
4. Staar, Cecie, and Ralph Taggart. "Information Flow and the Neuron."
Biology: The Unity and Diversity of Life. 9th ed. Pacific Grove: Brooks/Cole,
2001. 574-84. Print.