Chapter 12

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Chapter 12
2010-11-19 23:45:28
Anatomy Physiology Nervous System Cells

Chapter 12 Nervous System Cells
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  1. Nerves that lie in the outer regions of the nervous system
    • Peripheral Nervous System
    • (PNS)
  2. Originates from the brain
    Cranial Nerves
  3. Originates from the spinal cord
    Spinal Nerves
  4. Consists of all incoming sensory pathways
    Afferent Division
  5. Consists of all outgoing motor pathways
    Efferent Division
  6. Carries information to the somatic effectors (skeletal muscles)
    Somatic Motor Division
  7. Carries feedback information to somatic integration center in the Central Nervous System
    Somatic Sensory Division
  8. Prepares the body to deal with immediate threats to the internal enviroment; produces fight or flight response
    Sympathetic Division
  9. Coordinates the body's normal resting activities; sometime called the "rest and repair" division
    Parasympathetic Division
  10. conduct impulses away from spinal cord or brain toward muscles or glandular tissue
    Efferent (motor) Neurons
  11. conduct impulses to spinal cord or brain
    Afferent (sensory) Neurons
  12. onle one axon and one dendrite; least numerous kind of neuron
  13. one process comes off neuron cell body but divides almost immediately into two fibers; central fiber and peripheral fiber
  14. one axon and several dendrites
  15. Dendrites and cell body are in what functional region of the neurons
    Input Zone
  16. Axon hillock are in what functional region of the neuron
    Summation Zone
  17. axon is in what function region of the neuron
    Conduction zone
  18. telodedria and synaptic knobs of axon are in what function region of the neuron
    Output zone
  19. a single process extending from the axon hillock, sometimes covered by a fatty layer is called a
    Myelin Sheath
  20. swellings that make contact (synapse) with other cells
    Axon varicosites
  21. small knoblike protrusions on dendrites of some brain neurons; serve as connection points for axons of other neurons
    Dendritic Spines
  22. conducts impulses to the CNA from the receptors
    Afferent neurons
  23. conduct impulses from the CNS to effectors (muscle or glandular tissue)
    Efferent neurons
  24. most common; consists of afferent neurons, interneurons, and efferent neurons
    Three-neuron arc
  25. simplest form; consists of afferent and efferent neurons
    Two-neuron arc
  26. nerves with predominatly motor neurons
    Motor Nerves
  27. nerves with predominantly sensory neurons
    Sensory Nerves
  28. in gray matter and referred to as nuclei
    • CNS
    • (Central Nervous System)
  29. in gray matter referred to as ganglia
    • PNS
    • Peripheral Nervous System
  30. in white matter the myelinated nerves
    • PNS
    • (Peripheral Nervous System)
  31. in white matter the myelinated tracts
    • CNS
    • (Central Nervous System)
  32. fibrous coat surrounding numerous fascicles and blood vessels to form a complete nerve
  33. connective tissue holding together fascicles (bundles of fibers)
  34. delicate layer of fibrous connective tissue surrounding each nerve fiber
  35. bundles fo peripheral nerve fibers held together by several layers of connective tissue
  36. when a stimulus triggers the opening of additional K+ channels, increasing the membrane potential (hyperpolarization)
  37. whena stimulus triggers theopening of additionl na+ channels, allowing the membrane potential to move toward zeoro (depolarization)
  38. slight shift ways formt he resting membrane in a specific region of the plasma membrane
    Local potentials
  39. a membrane that exhibits a membrane potential
    Polarized Membrane
  40. slight excess of positively charged ions on the outside of the membrane and slight deficientcy of positively charged ions on the inside of the membrane
    Membrane potential
  41. the membrane potential of a neuron that is conducting an impulse; also known as a nerve impulse
    Action potential
  42. brief period (0.5ms) during which a local area of a neuron's membrane resists restimulation and will not respond to a stimulus, no matter how strong
    Absolute Refractory Period
  43. time during which the membrane is repolarized and restoring the resting membrane potential; the few milliseconds after the absolute refractory period; will respond only to a very strong stimulus
    Relative refractory period
  44. occurs where cells joined by gap junctions allow an action potential to simply contine along postsynaptic membrane
    Electrical Synapses
  45. occur where presymaptic cells release chemical transmitters (neurotransmitters) across a tiny gap to the postsymaptic cell possible inducing an action potential there
    Chemical Symapses
  46. timy buldge at the end of a terminal branch of a presymaptic neuron's axon that contains vesicles housing neurotransmitters
    Symaptic Knob
  47. space between a symaptic knob and the plasma membrane of a postsymaptic neuron
    Symaptic Cleft
  48. axon signals postsynaptic dendrite; common
  49. axon signals postsynaptic soma; common
  50. axon signal postsynaptic axon; may regulate action potential of postsynaptic axon
  51. adding together the effects of several knobs being activated simultaneously and stimulating different locations on the postsynaptic membrane producing an action potential
    Spatial Summation
  52. when synaptic knobs stimulate a postsynaptic neuron in rapid succession, their effects can summate over a brief period of time to produce an action potential
    Temporal Summation
  53. stored by facilitating (or inhibiting) synaptic transmission
  54. (sec or min) may result from axoaxonic facilitation or inhibition of the presynaptic axon terminal
    Short-term Memories
  55. (min to weeks) happens when serotonin blocks potassium channels in the presynaptic terminal thus prolonging the action potential and increasing the amount of neurotrasmitter released
    Intermediate long-term memory
  56. (month or yrs) requires structural changes at the synapse
    Long-term memory
  57. means by which neurons communicate with one another; more than 30 compounds
  58. the mechansim by which neurotrasmitters cause a change; function vary by location, they are usually classified according to chemical structure
    Chemical Structure
  59. neuropeptides
    Large molecule neurotrasmitter
  60. (nerve growth) stimulate neuron development but can act as neurotrasmitter
  61. proposes neuron is basic structural and function unit of the nervous system and neurons are independent units connected by chemical synapses
    Neuron Doctrine
  62. proposes nervous system is best unerstood as a large integrated network
    Reticular Theory
  63. act as receptors to detect changes in the internal and external environment; relay information to integrator mechanisms in the CNS
    Sensory neurons
  64. tumors arising in nervous system structure
  65. a common type of brain tumor
  66. a type of brain tumor (glioma) that originates from astrocytes
  67. a highly malignant form of astrocytic tumor that spreads throughout the white matter of the brain
    Glioblastoma Multiforme
  68. a glial tumor arising from ependymal cells which line the fluid filled cavities of the brain and spinal cord
  69. tumor that commonly occurs in the anterior portion of the brain and has a perak incidence at 40 yrs of age. Would be glioma of oligodendrocytes
  70. a lesion of the sheath of Schwann cells surrounding the eighth cranial nerve, responsible for hearing and balance
    Acoustic Neuroma
  71. is an inheritied disease characterized by numerous fibrous neuromas throughout the body
    Multiple neurofibromatosis
  72. the enzyme that inactivates dopamine and serotonin
    Monoamine Oxidase (MAO)
  73. nerve growth factors that are release by various cells of the body