Neuropath- Part 1

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Mawad
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308778
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Neuropath- Part 1
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2015-10-02 11:11:48
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vetmed neuropathology
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vetmed neuropath
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  1. Functions of the NS. (5)
    muscle contraction, sensory, metabolic, immune, integrative/cognitive
  2. Terminally differentiated neuroepithelial derivative.
    neuron
  3. Means of electrochemically transmitting information.
    axon
  4. _____________ of ions across ____________ create a membrane potential.
    Concentration differences; selectively permeable membranes
  5. Neurons have a high intracellular conc of _____.
    K+
  6. Neuronal plasma membranes are selectively permeable to _______, allowing it to move out of the cell down its conc gradient and creating a net _______ within the cell.
    K+; negative
  7. Membrane potential is established because _____ diffuses down its conc gradient out of the cell, but the ______ charge that builds within the cell attracts diffusing ______ against their conc gradient and back into the cell.
    K+; negative; K+
  8. Permeability of the membrane to _______ is low and constant; therefore, membrane potential is mainly controlled by __(2)__.
    Cl-; Na+ and K+
  9. Membrane potential is ______ (charge).
    negative
  10. At rest, extracellular concs of __(2)__ are high relative to inside the cell.
    Na+ and Cl-
  11. Everywhere except _____________, the negative and positive charges are ____________.
    adjacent to the surfaces of the cell membrane; exactly equal (electrical neutrality)
  12. The _____________ establishes the high intracellular K+ conc and low intracellular _____ conc.
    Na+K+ATPase pump; Na+
  13. ________________ is the primary basis for the -90mV membrane potential.
    K+ diffusion down its conc gradient out of the cell
  14. In the resting stage, the membrane is _________.
    polarized
  15. During membrane depolarization, the membrane suddenly becomes ____________, resulting in a massive influx; this leads to ______________.
    more permeable to Na+; elimination of membrane potential
  16. The influx of Na+ that leads to membrane depolarization is mediated by activation of ____________, which occurs through ____________ that caused a conformational change.
    voltage-gated Na+ channels; reduction of the membrane potential (from -90 to -50)
  17. The reduction in membrane potential necessary for activation of voltage-gated Na+ channels must be sufficient to _______________ and induce a ____________.
    surpass threshold of activation; positive-feedback loop of voltage-gated Na+ channel acitvation
  18. Depolarization will spread in __________ where ____________.
    all directions; resting/polarized membranes are encountered
  19. Repolarization is achieved due to the slow conformational change in a ___________. allowing ___________.
    voltage-gated K+ channel; efflux of K+
  20. Diffusion of ________ to the __________ re-establishes resting membrane potential.
    K+; exterior
  21. Na+/K+ concs are re-established by the ___________.
    Na+K+ATPase pump
  22. __________ is the most efficient way to generate ATP; therefore, the brain does not utilize __________; the implication of this is...
    Aerobic glycolysis; anaerobic metabolism; oxygen and/or glucose deficiency impair neuron conduction within 5-10 seconds
  23. Neurons utilize _________ almost exclusively for their energy demands.
    blood glucose
  24. Modulation of initiation/propagation of action potentials is driven by... (3)
    increased extracellular K+ (decreasing K+ leak channel), decreased extracellular Ca2+ (required to stabilize Na+ channel), inhibition of voltage-gated Na+ channels (ie. local anesthetics, toxins)
  25. Diminished K+ diffusion potential interferes with ___________.
    membrane repolarization
  26. ______ binds the extracellular domain of the voltage-gated Na+ channel, stabilizing the channel.
    Ca2+
  27. Reducing extracellular Ca2+ reduces the voltage at which __________; this results in __________.
    Na+ channels become activated; hyperexcitable neurons
  28. Depolarization proceeds along the length of the axon, reaching the __________, where stimulatory or inhibitory signals are transmitted downstream through the __________.
    presynaptic terminal (axon terminus); synaptic cleft
  29. Neurotransmitters are synthesized in the __________ or the _________ and are packaged in ___________.
    presynaptic terminal; neuron cell body; synaptic vesicles
  30. Depolarization of the presynaptic terminal activates ____________, allowing a(n) ___________.
    voltage-gated Ca2+ channels; influx of Ca2+ and Na+
  31. A rise in intracellular Ca2+ causes fusion of __________ with the _________, releasing ___________ into the __________.
    synaptic vesicles; plasma membrane; neurotransmitters; synaptic cleft
  32. What are the receptors types on postsynaptic neurons for neurotransmitters? (2)
    ion channels (binding results in opening channels to alter membrane permeability), enzyme receptors (cause internal metabolic change to alter reactivity of the neuron)
  33. Excitation of ion channel receptors results in opening __________; inhibition of ion channel receptors results in opening __________.
    Na+ channels; K+ channels
  34. Small molecule neurotransmitters are ________ acting and primarily affect __________.
    rapidly; conduction through ion channels
  35. Neuropeptide neurotransmitters are _________ acting and primarily affect ___________.
    slowly; enzyme receptors
  36. The junction b/w an axon terminus and muscle.
    motor end plate
  37. Motor end plates utilize ___________ neurotransmitters.
    small molecule, rapidly acting
  38. The 3 functional units of the nervous system.
    sensory, motor, processing/integratory
  39. The pattern of dendritic development is a reflection of ____________.
    neuronal function
  40. Maintains the functional integrity of the cellular processes; has great metabolic burden.
    neuron cell body
  41. The size of the cell body reflects ___________.
    the length of the axon it must support
  42. Extensive roughER in neurons is required for synthesis of __________, which is proteins and glycoproteins utilized in the maintenance of axonal and dendritic structure and function.
    nissl substance
  43. Communication b/w cellbody and axon is through ____________, which can be... (3)
    axoplasmic transport; fast antegrade (secretory vesicles, mitochondria), slow antegrade (cytoskeleton), retrograde
  44. ____________ and ___________ makes the neuron particularly susceptible to injury.
    High metabolic rate; specialization
  45. If integrative function of one neuron is lost, the function of the __________ is altered.
    entire circuit
  46. Depolarization events jump b/w _____________.
    Nodes of Ranvier (unmyelinated areas of axon)
  47. Schwann cells are in the _________; oligodendroglia are in the _________.
    PNS; CNS
  48. Neuroglia are... (5)
    oligodendroglia, astrocytes, ependymal cells, choroid plexus epithelia, microglia
  49. Palm-like cytoplasmic extensions progressively wrap around axonal processes, excluding cytoplasmic content.
    myelin
  50. _____________ a predominant membrane lipid constituting myeline that is an excellent insulator.
    Sphingomyelin
  51. In the CNS, ___________ stabilizes the multilamellar structure of myeline.
    myeline basic protein
  52. In the CNS, ____________ plays a role in induction of myelination.
    myelin-associated glycoprotein
  53. With __________, action potentials are restricted to exposed portions of the axon, or Nodes of Ranvier.
    saltatory conduction
  54. With saltatory conduction, currents lower the membrane potential and activate ____________ at the next __________, leading to ____________.
    voltage-gated Na+ channels; Node of Ranvier; depolarization of each node
  55. What are the advantages of saltatory conduction? (2)
    increased velocity of nerve impulse, conserves energy for neuron
  56. Functions of schwann cells. (3)
    myelination of nerve fibers, structural support for nerve fibers, support axonal metabolism
  57. Schwann cells produce __________ and _________, effectively creating...
    basement membrane; collagen; a tube through which the axon courses, the neurilemmal tract.
  58. The schwann cell:axon ratio in myelinated fibers is _____, which is important for ___________.
    1:1; reinnervation in the PNS
  59. Regeneration of an axon (reinnervation) is only successful if there is...
    a neurilemmal tract guiding the axon sprout to its destination.
  60. Schwann cells in the PNS are the functional equivalent of _________ in the CNS.
    astrocytes
  61. Myelination occurs late in fetal life and early into the post-natal period, thus...
    protracts the NS develop and increases the opportunity for developmental defects.
  62. Myelin can be replaced because __(2)__ retain the ability to proliferate.
    oligodendroglia and schwann cells
  63. Neuroectodermal derivative which retains the ability to replicate in the CNS.
    astrocytes
  64. __________ provide structural support to nervous tissue parenchyma via their extensive ___________.
    Astrocytes; cytoplasmic processes
  65. __________ may fill in or delineate tissue defects in the CNS, forming scar tissue.
    Astrocytes
  66. Functions of astrocytes. (4)
    structural support to CNS parenchyma, basic metabolic support to neurons and oligodendroglia, directly support neuronal signal transduction, form the BBB
  67. Astrocytes form a syncytium with other astrocytes via _________ in their cytoplasmic processes; thus, they are able to have...
    gap junctions; continuous communication for nutrition and waste removal.
  68. Astrocytes directly support neuronal signal transduction by... (3)
    terminate neurotransmitter stimulation, neurotransmitter recycling, reverses extracellular electrolyte imbalances that result from membrane repolarization
  69. __(2)__ form the blood brain barrier.
    Astrocyte processes and endothelial cells
  70. Resident macrophages of the brain and are unique amongst glial elements in that they are derived from mesenchyme.
    microglia
  71. Microglia have a key role as _________.
    antigen-presenting cells
  72. Cellular components of the grey matter of the CNS. (4)
    neuron cell bodies, astrocytes, oligodendrocytes, microglia
  73. Cellular components of the white matter of the CNS. (4)
    axonal processes, oligodendroglia an myelin, astrocytes, microglia
  74. Components of the PNS. (2)
    ganglia/plexus, nerve fibers
  75. Ganglia/plexus of the PNS are composed of... (2)
    neuron cell bodies, sustenacular cells
  76. Nerve fibers of the PNS are composed of... (3)
    axonal processes, schwann cells, fibrous connective tissue
  77. _____________ occurs as ingrowth during embryogenesis and is necessary for nutrition and waste removal.
    Vascularization
  78. Doe grey or what matter have more vascularization and metabolic activity?
    grey matter
  79. The BBB is permeable to... (2)
    lipid soluble compounds, (slightly) electrolytes.
  80. The BBB is impermeable to... (2)
    plasma proteins, large (water soluble) organic compounds.
  81. What is the anatomic basis for the BBB?
    non-fenestrated capillary endothelial cells with tight junctions b/w cells
  82. The basal lamina upon which the endothelium of the BBB rest is surrounded by ____________.
    astrocytic foot processes
  83. Functions of CSF. (3)
    waste removal supply of metabolites, protective cushion for nervous tissue
  84. The __________ is responsible for CSF production.
    choroid plexus
  85. The choroid plexus is composed of specialized structures in the...
    lateral ventricles and roof of the third and fourth ventricles.
  86. Choroidal epithelia are specialized ___________ responsible for CSF production.
    ependymal cells
  87. Capillaries of the choroid plexus have __________ endothelium, with __________ of the choroidal epithelium, creating the blood-CSF barrier.
    fenestrated; tight junctions
  88. For CSF production, _______ is actively transported into the ventricular system by the ___________, carrying __(2)__ along with it; __(2)__ are actively transported out of CSF.
    Na+; Cl- and water; K+ and bicarb
  89. What are the functions of CSF? (3)
    waste removal, metabolite supply, protective function
  90. The _______ of the brain and the ________ of the spinal cord contain CSF.
    ventricular system; duct system
  91. CSF is resorbed in the _________.
    subarachnoid space
  92. Describe the flow of CSF from where it is produced to the spinal cord.
    lateral ventricles--> interventricular foramen--> third ventricle--> mesencephalic aqueduct--> fourth ventricle--> lateral apertures to the subarachnoid space--> spinal cord central canal
  93. The subarachnoid space is created by the _________.
    meninges
  94. The tough fibrous connective tissue covering that protects the brain and spinal cord from penetrating injury and forms the periosteum of the interior surface of the cranial vault.
    dura mater/ pachymeninges
  95. The deicate collagen and reticular fibers that send supportive trabeculae to the pia mater.
    arachnoid membrane/ leptomeninges
  96. What are the 2 components of the leptomeninges?
    arachnoid membane and pia mater
  97. Layer of the meninges that is intimately associated with the surface of the brain and spinal cord.
    pia mater/leptomeninges
  98. The subarachnoid space is b/w the _________ and _________ and is filled with _________.
    arachnoid membrane; pia mater; CSF
  99. Glial cells of neuroectodermal origin that have apical cilia that cause the continuous movement of CSF into the subarachnoid space.
    ependymal cells
  100. _________ lined by ependymal cells extend into the dorsal sagittal sinus, permitting the resorption of CSF.
    Arachnoid granulations
  101. The perivascular space is where ____________ occurs.
    modification of CSF composition
  102. The CNS corollary to lymphatics of other organ systems.
    perivascular space
  103. The perivascular space is potential space b/w the _________ and the __________.
    endothelial basement membrane; basement membrane of the pia mater
  104. Why does the CNS lack a classical lymphatic draining system, and how does it overcome this?
    due to the presence of the BBB; when fluid escapes, it accumulates in the perivascular space and then passes through the subarachnoid space to the arachnoid vili to be resorbed
  105. Due to the BBB, vascular leakage in the CNS occurs only in association with...
    inflammation or other pathologic processes that increase vascular permeability.
  106. Finger-like extensions of the arachnoid membrane that project into large venous sinuses; cells contain valve-like pores to permit unidirectional flow of material from the subarachnoid space into venous circulation.
    arachnoid villi
  107. _________________ is the primary determinant of CSF pressure.
    Rate of absorption into arachnoid villi
  108. Clusters of arachnoid villi.
    arachnoid granulations
  109. CSF passing along cranial nerves and spinal nerve roots, going into lymphatics does not play a major role in CSF pressure; it does, however, play a major role in...
    initiating adaptive immune responses for processes that begin in the CNS.

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