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39 Cards in this Set
- Front
- Back
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What is the diameter of a neuron cell body?
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10 – 50 microns
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The longest axon projections from...
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cortex and project down to the bottom of the spinal cord
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Diameter of axon?
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0.2-20 μm diameter
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Longest axon
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one meter in length
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Most vertebrate neurons are?
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Multipolar neurons
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Neurons found in the retina and olfactory epithelia are usually?
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bipolar neurons
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Neurons of the dorsal root ganglion are?
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Psuedo-unipolar nuerons
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Unipolar neurons are found where?
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Authnomic nervous system, and invertebrates
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These nerve cells have no dendrites?
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pseudo-unipolar
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Cajal realized that...
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each neuron is an individual entity and that neurons interact with each other through synaptic communication
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Cajal's doctrine is called...
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The neuron doctrine
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4 forms of cell-cell communication:
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1. Endocrine communication
2. Paracrine communication 3. Synaptic communication 4. Contact-dependent communication |
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Synapses can occur on all parts of the neuron. Synapses that occur on the axon are called?
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Axo-axonic syanpses
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Synapses that occur on the dendrite are called?
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Axo-dentridic synapses
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Syanpses that occur on the soma are called?
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Axo-somatic synapses
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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
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True
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Size of synaptic cleft?
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200-300Å
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Synaptic terminal contains...
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large number of mitochondria and vessels of neurotransmitter
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Size of neurotransmitter vesicles...
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400-6000 Å diameter, containing neurotransmitter and neuropeptide substances for released
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Besides neurons, what other cells are intimately involved in the functions of the nervous system?
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Glia cells
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Glia cells are separated into what 2 groups?
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1. Microglia
2. Macroglia |
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What 2 categories of macroglia are there?
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1. Myelin-forming cells
2. "Supporting" Cells |
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Myelin-forming cells in the CNS are called...
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Oligodendrocytes
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Myelin-forming cells in the PNS are called...
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Schwann Cells
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What are the 2 types of Supporting Cells?
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1. Astrocytes
2. Satellite cells |
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Astrocytes are in which part of the nervous system?
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CNS
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Satellite cells are in which part of the nervous system?
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PNS
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Whatever we say about astrocytes also applies to...
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Satellite cells
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Again, what is the function of microglia?
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• 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. |
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Function of astrocytes (and also satellite cells)
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• 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. |
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Function and location of schwann cells.
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• Derived from neural crest, serve as support cells and myelinating cells of
the PNS. Can also act as phagocytes, and produce cytokines. |
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How many neurons does an oligodendrocyte wrap around?
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1 cells wraps around several axons
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How many neurons does a schwann cell wrap around?
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1 cell per axon, but it can cover unmyelinated axons
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Name a demyelination disease:
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Multiple Sclerosis
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Name a demyelination disease:
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Multiple Sclerosis
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Schwann cells and satellite cells might be seen in what nerve?
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Peripheral nerves
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This surrounds individual axons, Schwann cells and blood vessels
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Endonerium
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This surrounds groups of fibers to form fasciles:
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Perinerium
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This binds several fasicles into a nerve trunk:
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Epinerium
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