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Glial cells...Neurons....and the SYNAPSE

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Glial cells...Neurons....and the SYNAPSE

Postby segarama » Mon Oct 31, 2005 6:36 pm

:) Well, the neuron seems to have a huge independent glial cell system to help support it . By this I mean that we have glial cells that help myelinate axons of the neuron thus allowing communications such as action potential(s) to reach the axon terminals/presynaptic and then cross the synaptic cleft to the postsynaptic receptors.

The neuron would not function in an efficacious manner if the myelin was cracked or degenerated....so we have the oligodentrocytes and other glial cells to help remyelinate. The glial cell also supports the maintenance of the neuron by cleaning up the debris causes by wear and by apoptosis. What a good system...until disease destroys the glial cells which in turn causes helplessness in the neuron.

Now we are finding that the glial cells have many functions with more being discovered often. However what keeps the synapse free from dead cells and waste...Does it just stay unmaintained? Someone must know how the synapse is maintained....free of debris and dead cells....Someone?
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Rob
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Postby mith » Tue Nov 29, 2005 3:57 am

would that be the glial cells again? Such as microglia?
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Postby segarama » Tue Nov 29, 2005 1:43 pm

mithrilhack wrote:would that be the glial cells again? Such as microglia?


:shock: You may be right......Take a look at the Dana Foundation Neuroscience Newsletter for December 2005. The headlines read Rethinking the Synapse: Emerging Science Challenges Old Assumptions.....Please order the Neuroscience Newsletter call Brain Works and ask for Vol. 15 no.6 November-December 2005...You will get them about every month...It is up to date and GREAT.
http://www.dana.org/books/press/brainwork/
Be well,
Rob :roll:

The Glial cell is an important part of the synapse....I thought so......
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Postby MrMistery » Tue Nov 29, 2005 7:36 pm

Yes that is true. One of the roles of glial cells is to phagocytate dead neurons and other dead glial cells. Unfortunately Dave got it wrong, at least according to my physiology professor. She told us that it is mainly astrocytes have this function.
Microglia is formed from glioblasts(young glial cells or resting glial cells). However i did find in some books that these glioblasts are mobile.
By the way, the name of the glial cells that secrete the myelin sheath in peripherical nervous system is Schwamm cells. Amyelinic axons also have schwamm cells, and even some myelin, but the layer is to thin and it can not do it's job of isolation of the axon.
The main difference between oligodentrocytes and Schwamm cells is that 1 schwamm cell secretes myelin for one axon, while 1 oligodentrocyte secretes myelin for more axons(by the way, it is not actually a secretion process)
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Postby mith » Tue Nov 29, 2005 10:15 pm

huh, I hope someone can clarify this but my book says microglia mainly phagocytize and are near blood vessels, while astroglia have multiple functions including phagocytosis.

It also said schwann are only involved in the peripheral nevous system's neurons while the oligodentrocytes wrap around the CNS neurons.
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Postby segarama » Wed Nov 30, 2005 6:28 am

Good evening....
Schwann cells are in the PNS....and treat myelination of axons. Oligodendrocytes are in the CNS and treat myelination of the axon. That is all I know for sure for tonight......Be well.
Best,
Rob
Last edited by segarama on Wed Nov 30, 2005 7:48 pm, edited 2 times in total.
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Postby segarama » Wed Nov 30, 2005 7:28 pm

The myelin project at URL http://www.myelin.org/
has a great deal of information that we are looking for....the graphic are terrific...actually I believe you will find two or three excellent graphics. The graphics on the first page shows an oligodendrocytes [glial cell ]remyelinating an axon of a neuron in the CNS.
The other graphic that you must see, shows a nomal neuron and normal myelin with the message going through the axon undisturbed. The otherside of the same screen show a diseased myelin sheath along with a dying oligodendrocytes [glial cell]....CNS...this is what MS looks like in some cases. Diseased cell url: http://www.myelin.org/diseasesinbrief.htm
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Postby MrMistery » Wed Nov 30, 2005 9:23 pm

mithrilhack wrote:huh, I hope someone can clarify this but my book says microglia mainly phagocytize and are near blood vessels, while astroglia have multiple functions including phagocytosis.


Quite strange... Man, why can't they agree upon one opinion. What book are you studying from?

mithrilhack wrote:It also said schwann are only involved in the peripheral nevous system's neurons while the oligodentrocytes wrap around the CNS neurons.

I don't believe i said anything different.
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Postby MrMistery » Wed Nov 30, 2005 9:26 pm

Update:
I just found in an anatomy compendium that they main function of microglia is phagocytosis... I hate conflicting books!!
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