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63 Cards in this Set
- Front
- Back
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Difference btwn Neurons and Glia in terms of:
• Cell division • Cell regeneration • Signalling and/or Supportive roles • Mode of excitability |
Difference btwn Neurons and Glia in terms of:
• Cell division - Neurons do not divide but glial cells do • Cell regeneration - Neurons regenerate only under certain conditions whereas glial cells normally always do • Neurons participate in signalling whereas glial cells have both signaling and supportive roles • Mode of excitability - Neurons by Action and synaptic potentials; Glial cells by NTs and Ca2+ signaling |
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Multipolar neurons:
• Two characteristics • an example |
Multipolar neurons:
• Have 3+ dendrites and one long axon coming from the cell body • Motor neurons from the ventral horn of the spinal cord |
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Bipolar neurons:
• Two characteristics • Two examples |
Bipolar neurons
• Have an elongated cell body and two processes arising from the cell body, one being the dendrites and the other the axon with terminals • Retinal bipolar cells and Sensory neurons of the cochlea |
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Pseudo-unipolar:
• Main structural feature • How information is collected and transmitted • Two examples |
Pseudo-unipolar:
• A single process arises from the cell body and divides into two branches, one going towards the periphery and the other towards the CNS • Information is gathered from the PNS branch and transmitted towards the CNS terminals • DRG and baro-receptor cells in the nodose ganglia |
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Main feature of Unipolar neurons
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The axon and dendrites arise from the same side of the neuron
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Unmyelinated axons can be found in these regions of the mammalian CNS
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Hippocampus and cortex
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Define a pure white matter tract and give an example
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One that is completely myelinated
ex. optic nerve |
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A part of the brain that has both grey and white matter portions
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corpus callosum
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How information is encoded along the membranes of neurons
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encoded as frequency of impulses
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The system that classifies spinal nerves
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Erlanger & Gasser
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The Lloyd system classifies these types of nerves
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afferent fibers of skeletal muscle
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The 6 types of spinal nerve fibers as classified by Erlanger and Gasser
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A (-alpha, -beta, -gamma, -delta)
B C |
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The 5 types of skeletal muscle afferent fibers as characterized by Lloyd
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Ia, Ib, II, III, IV
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A-alpha:
• type of fibers • fxn • conduction velocity |
A-alpha:
• spinal motor and sensory • motor - serve extrafusal muscle fibers sensory - carried from muscle spindles • 72 - 120 m/s |
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A-Beta:
• type of fiber • fxn • conduction velocity |
A-beta:
• sensory • carries pain and mechano receptor signals from skin • 36 - 72 m/s |
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A-gamma:
• type of fiber • fxn • conduction velocity |
A-gamma:
• motor • intrafusal muscle fibers • serving 18 - 36 m/s |
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A-delta:
• type of fiber • fxn • conduction velocity |
A-delta:
• sensory • carries pain and temperature signals • 4 - 36 m/s |
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B:
• type of fiber • fxn • conduction velocity |
B:
• preganaglionic neuron of the ANS • fxns in the ANS • 4 - 18 m/s |
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C:
• type of fiber • fxn • conduction velocity |
C:
• sensory fiber • carries pain and temperature signals • 0.5 - 2 m/s |
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Class Ia fiber:
• type of fiber • the origin of their info • conduction velocity |
Class Ia fiber:
• sensory • primary endings in muscle spindles • 72 - 120 m/s |
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Class Ib fiber:
• type of fiber • the origin of their info • conduction velocity |
Class Ib fiber:
• sensory • Golgi tendon organs in muscle • 72 - 120 m/s |
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Class II fiber:
• type of fiber • the origin of their info • diameter • conduction velocity |
Class II fiber:
• sensory • 2ndary ending in muscle spindles • 6 - 12 microns • 36 - 72 m/s |
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Class III fiber:
• type of fiber • the origin of their info • conduction velocity |
Class III fiber:
• sensory • mechano-sensitive endings in muscle • 4 - 36 m/s |
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Class IV fiber:
• type of fiber • the origin of their info • conduction velocity |
Class IV fiber:
• sensory • pain sensitive endings in muscle • 0.4 - 2 m/s |
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Three types of cytoskeletal filaments
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Microtubules, neurofilaments or intermediate filaments, microfilaments
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Microtubules participate in a two axonal transport system, moving material btwn these two points
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They move material btwn soma and the nerve ending
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MAPs:
• this is one example that stabilizes microtubules • these two proteins participate in fast axonal transport |
MAPs:
• Tau • kinesin and dynein |
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Neuro- / Intermediate filaments:
• are the most common filaments in these cell types • are notably absent in this cell • its turnover rate in comparison to the other cytoskeleton filaments • Human neurofilaments are formed by these 3 proteins • four examples |
Neuro- / Intermediate filaments:
• neurons and astroglia • oligodendricytes • has low turnover rate in comparison • NFL, NFM, NFH • Neuronal neural filament group, glial GFAP, nestin and vimentin |
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Microfilaments:
• a network of MFs are made of these specific filaments • the network is formed just below this structure • participates in the advancement of this structure during these two processes • has an active role in this form of recycling • two examples of |
Microfilaments:
• actin • the cell membrane • advancement of the growth cone during these neuronal growth or repair • synaptic vesicle endocytosis during vesicle recycling • actin and spectrin |
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Kinesin:
• Two ways to classify this protein • responsible for this kind of transport, include transport rate • the material it transports (2) • this happens to it when it reaches the nerve ending |
Kinesin:
• a MAP and ATPase • fast anterograde transport, 100 - 500 mm/day • vesicles and mitochondria • It becomes inactivated and is carried back to the soma via retrograde axonal transport |
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Dynein:
• Two ways to classify this protein • responsible for this kind of transport, include transport rate • the material it transports (3) • this happens to it when it reaches the soma • An important molecule transported by Dynein |
Dynein:
• a MAP and ATPase • fast retrograde transport, 200 - 300 mm/day • lysosomes, enzymes, recycled vesicular membrane • It becomes inactivated and is carried back to the nerve endings • NGF |
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There are two types of slow anterograde transport:
• their rate • what each transports • this transport does not account for the transport rates of these cellular components |
SC B. (1 - 10) mm/day; soluble proteins and enzymes
SC A. (0.1 - 1) mm/day; cytoskeleton molecules It does not account for the transport rates of proteins and organelles in axons |
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The four morphological classes of astrocytes present in the human brain and where they are found
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1. Interlaminar - cortical layer 1
2. Protoplasmic - cortical layers 2 - 6 3. Varicose projection - cortical layers 5 & 6 4. Fibrous - in white matter |
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Two derivatives of radial glial cells and where they are found
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• Bergman glia in cerebellum
• Muller cells in the retina |
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The excitability of glial cells is based on this
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changes to intracellular [Ca2+]
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Three examples of gliotransmitters
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glutamate, D-Serine, ATP
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Name for astrocytes associated with neurovascular units and their roles
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Perivascular astrocytes, maintaining cerebral blood flow and ionic & osmotic balances in the brain
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Glial scars:
• how they are formed • a consequence |
Glial scars:
• head trauma, ischemia or a neuronal disease such as Alzheimer's • they isolate neurons from each other |
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How astrocytes provide the CNS with an alternate form of ATP production
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They are the main storage site for glycogen in the brain and is used when [glucose] is in crisis. Glycogen is converted to lactate. The storage molecule is used up after ~10min.
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How astrocytes regulate the [K+] in the neuronal ECF and the names of the fxn
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Astrocytes contain K+ channels which remove the ion from the fluid and distribute in throughout its own cell and through gap jxns to its neighbors.
Called K+ siphoning or spatial buffering. |
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Astrocytes' role in the synaptic cleft and the type of receptors it has
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Absorb Neurotransmitters.
Contain ionotropic and metabotropic receptors. |
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Summarize some of the main roles of astroglia in the CNS (7, only 4 were discussed above)
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• Maintain cerebral blood flow through ionic & osmotic balances
• Store glycogen and supply neurons with lactate during substrate crisis • Spatial buffering/K+ siphoning • maintaining homeostasis of neuronal signaling at the synapse • release antioxidative enzymes to protect neurons against oxidative damage • determine the fate of endogenous neural precursors through the release of growth factors • release cholesterol which helps in increasing the number of synapses |
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This happens to astroglia as a result of ischemia or head trauma
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they swell
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Two key words to describe macroglia cells of the CNS
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Immunocompetent and phagocytic
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Multiple sclerosis is a neurological d/o mainly involving this cell
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oligodendrocytes
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Ependymal cells:
• form the walls of this structure • are primary cells that produce neurons and glia after this event |
Ependymal cells:
• forms the walls of the ventricles • produce neurons and glia after stroke |
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Two roles of choroid plexus epithelial cells
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secrete CSF
transfer molecules from blood into the CSF |
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Tanycytes:
• are produced during development from these cells • are 4 separate populations of this morphological cell type • are a specialized group of these cells and are found in this area • are implicated in the transport of these molecules btwn these areas (4) |
Tanycytes:
• from radial glia • are 4 separate populations of bipolar cells • ependymal cells, found in the floor of the 3rd ventricle • hormones; from the CSF to capillaries of the portal system, from the hypothalamic neurons to the CSF |
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Satellite glial cells:
• surround neurons from these ganaglia (3) • have this general fxn |
Satellite glial cells:
• Sensory, Sympathetic and Parasympathetic • regulating the external chemical environment |
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Four types of neuronal degeneration, where the degeneration occurs on the axon/neuron
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• Wallerian - degeneration occurs distal to the site of axonal injury
• Chromatolysis - degeneration occurs close to the cell body, the site of injury • Anterograde - Degeneration occurs postsynaptic to the damaged neuron • Retrograde - Degeneration occurs in the neuron sending signals to the injured neuron |
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This happens to the neuron and its organelles as a result of chromatolysis
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The cell swells due to edema and its organelles, especially the nucleus, shift away from the cell body, towards the periphery
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4 examples of CNS tumors
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Glioblastoma, Astrocytoma, Oligodendroglioma, Ependymoma
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PNS tumors usually are of this origin
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Nerve sheath cells (Schwannomas)
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PNS tumors are usually found at these places (4)
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CNs, spinal nerve roots, peripheral nerves, SCG
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Alexander Disease:
• Due to an accumulation of this protein • 3 pathological characteristics |
Alexander Disease:
• GFAP • High levels of GFAP in the CSF, loss of myelin, degeneration of white matter in the brain |
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Gliosis:
• Two causes related to a type of glial cell • Two reasons why the axonal regeneration is inhibited |
Gliosis:
• Hyperplasia and hypertrophy of astrocytes in response to CNS injury • The production of glial scars, Reactive astrocytes phagocytosing degenerated nerve structures in the CNS |
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Pathological pain:
• Can be mediated by these glial cells • involves the the secretion of diffusible transmitters, name 3 |
Pathological pain:
• Astrocytes • interleukins, ATP and NO |
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ALS:
• time of onset • cellular characteristic • Cause of the familial d/o • The cells involved in the d/o responsible for disease progression and severity (one for each) |
ALS:
• adulthood • loss of brain and spinal cord motor neurons • Dominant mutations in the Superoxide dismutase gene • Disease progression: SOD1-mutated astrocytes Severity of the diseases: Microglial cells |
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Progressive demyelinating neuroinflammatory disease:
• an example (two names) • etiology • two results |
Progressive demyelinating neuroinflammatory disease:
• HTV-1-associated myelopathy (HAM) or Tropical Spastic Parapesis (TSP) • viral intrusion of the CNS • Death of oligodendrocytes, axonal degeneration |
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Multiple sclerosis:
• general description • proposed cells that trigger the disease and its mode of action • cells that are targeted/damaged |
Multiple sclerosis:
• Chronic inflammatory/autoimmune disease of the CNS • Myelin antigen-specific CD4 T-cells; they are activated in the peripheral immune compartment, cross the BBB and trigger the disease • oligodendricytes |
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Guillain-Barr Syndrome:
• general description • what it affects (two components of nerves) • May lead to this type of neuronal degeneration • Clinical manifestations (3) • Two common tx |
Guillain-Barr Syndrome:
• Polyneuropathy - inflammatory demyelinating disease of the PNS • myelin sheath and axons • Wallerian • Progressive motor and sensory loss, elimination of deep tendon reflex arcs • Gamma globulin administration, plasma exchange |
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Charcot-Marie Tooth d/o:
• etiology • what it forms on the axon |
Charcot-Marie Tooth d/o:
• mutations in the gene encoding periaxin, a myelin structure maintaining protein • results in the formation of internodes, short segments of myelin |
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Examples of viruses that use retrograde transport and through which organ they use to enter axons
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Herpes, Polio, Rabies; they enter the axons via the skin
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