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What is the diameter of a neuron cell body?
10 – 50 microns
The longest axon projections from...
cortex and project down to the bottom of the spinal cord
Diameter of axon?
0.2-20 μm diameter
Longest axon
one meter in length
Most vertebrate neurons are?
Multipolar neurons
Neurons found in the retina and olfactory epithelia are usually?
bipolar neurons
Neurons of the dorsal root ganglion are?
Psuedo-unipolar nuerons
Unipolar neurons are found where?
Authnomic nervous system, and invertebrates
These nerve cells have no dendrites?
Cajal realized that...
each neuron is an individual entity and that neurons interact with each other through synaptic communication
Cajal's doctrine is called...
The neuron doctrine
4 forms of cell-cell communication:
1. Endocrine communication
2. Paracrine communication
3. Synaptic communication
4. Contact-dependent communication
Synapses can occur on all parts of the neuron. Synapses that occur on the axon are called?
Axo-axonic syanpses
Synapses that occur on the dendrite are called?
Axo-dentridic synapses
Syanpses that occur on the soma are called?
Axo-somatic synapses
True or false: a synapses occuring on the cell body or axon terminal would have a much greater effect on the output of the cell, as compared to one of the tens of thousands of synapses that occur on the dendrite
Size of synaptic cleft?
Synaptic terminal contains...
large number of mitochondria and vessels of neurotransmitter
Size of neurotransmitter vesicles...
400-6000 Ã… diameter, containing neurotransmitter and neuropeptide substances for released
Besides neurons, what other cells are intimately involved in the functions of the nervous system?
Glia cells
Glia cells are separated into what 2 groups?
1. Microglia
2. Macroglia
What 2 categories of macroglia are there?
1. Myelin-forming cells
2. "Supporting" Cells
Myelin-forming cells in the CNS are called...
Myelin-forming cells in the PNS are called...
Schwann Cells
What are the 2 types of Supporting Cells?
1. Astrocytes
2. Satellite cells
Astrocytes are in which part of the nervous system?
Satellite cells are in which part of the nervous system?
Whatever we say about astrocytes also applies to...
Satellite cells
Again, what is the function of microglia?
⬢ Invade brain during fetal development and maintain residence in
parenchyma. Responsible for response to injury to trauma in brain by
proliferation and phagocytosis of debris. Spider-like cells.
Function of astrocytes (and also satellite cells)
• Convert to different shapes, depending on function. Intimate associations
with blood vessels, ventricles, neurons, synaptic terminal zones.
• Processes extend around terminals. May serve to control diffusion of
released neurotransmitters.
• Store, buffer and release ions, transmitters. Have receptors, and some even
form synapses.
• Communicate with each other, and with neurons, via gap-junctions.
• High producers of cytokines that “nurse” cells.
Function and location of schwann cells.
⬢ Derived from neural crest, serve as support cells and myelinating cells of
the PNS. Can also act as phagocytes, and produce cytokines.
How many neurons does an oligodendrocyte wrap around?
1 cells wraps around several axons
How many neurons does a schwann cell wrap around?
1 cell per axon, but it can cover unmyelinated axons
Name a demyelination disease:
Multiple Sclerosis
Schwann cells and satellite cells might be seen in what nerve?
Peripheral nerves
This surrounds individual axons, Schwann cells and blood vessels
This surrounds groups of fibers to form fasciles:
This binds several fasicles into a nerve trunk:

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