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2011-11-14 17:54:02

Chapter 11: Nervous System and nervous Tissue
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  1. Describe the nervous System?
    • The master control and communication center of the body
    • and controls cells of the body using nerve cells called neurons and chemical and electrical signals
  2. What are the functions of the Nervous System?
    • Sensory Input
    • Intergration
    • Motor Output
  3. Sensory input
    Monitoring changes in the chemical environment ( iNside and outside of the body)
  4. Intergration
    Processing and interpreting the information and making a decision about how to respond
  5. Motor Output
    The response usually involving control of muscles and glands
  6. Central Nervous System
    CNS- the integration and command center to include the brain and spinal cord
  7. Peripheral Nervous System
    PNS-The sensory (afferent) and motor (efferent) nerves that receive/relay information to organs and glands communication lines
  8. Afferent
    (sensory)- carry toward
  9. Efferent
    (motor)- carry away
  10. Somatic Nervous System
    Voluntary movement or control using skeletal muscles
  11. Autonomic Nervous System
    (ANS)- involuntary actions including digestion, heart rhythm, breathing and other subconscious commands
  12. Sympathetic Nervous sysem
    • The accelerator system for flight or fight
    • Hype up
  13. Parasympathic Nervous System
    • The brake system for fight or flight
    • Calms down
  14. What is the nervous tissue made up of?
    • Neurons
    • Neurogila
  15. Neurons
    • The active cells that transmit electrical and chemical signals
    • extreme longevity if given nutrition
    • Amitotic (dont divide or replace)
    • High Metabolic rates (require continuous supplies of oxygen and glucose
    • Conduct impulses from one part of body to another
    • The structural unit of nervous system
  16. Neurogila
    (Glial Cells) The cells that support and maintain neurons
  17. What are some of the Neurogila in the CNS?
    • Astrocytes
    • Microgila
    • Ependymal cells
    • Oligodendrocytes
  18. Astrocytes
    • most abundant
    • attaches to capillaries and to neurons and their synaptic endings
  19. What are Astrocytes function?
    • determines capillary permeability
    • the migration of young neurons and in synapse formation
  20. Microgila
    • Deects neuron injury and differentiates into macrophages which engolf dead cells, pathogens and debris
    • Defensive cells
  21. Ependymal Cells
    the cavities of the brain and spinal cord and when ciliated, aids in the movement of the cerebrospinal fluid (produced by this cell)
  22. Oligodendrocytes
    • Covers the axons of the nerves in the CNS and formsan insulating covering called the Myelin sheath.
    • Helps speed up
  23. What are the Neuroglia in the PNS?
    • Satellite Cells
    • Schwann Cells
  24. Satellite Cells
    • Surrounds cell bodies of the nerves and aids in gathering nutrients for the Neurons
    • (Simillar to the Astrocytes in CNS)
  25. Schwann Cells
    • Surround the axons of neurons and forms the myelin sheath and aids in the regeneration of damaged peripheral nerve fibers
    • (Similiar to the Oligodendrocytes in the CNS)
  26. Soma
    • The Cell Body or Prokaryon
    • contains the nucleous and the majority of the cytoplasm and organelles
  27. The rough ER of a neuron is called
    Nissl Bodies
  28. Neurofibrils
    • Maintain the cell shape and integrity
    • Bundles of intermediate filaments within the cell body
  29. What are clusters of cell bodies within the CNS called?
  30. What are clusters of cell bodies within the PNS called?
  31. What are processes?
    • They extend from the cell bodies of all neurons
    • Dendrites
    • Axon
    • Myelin Sheath
    • Neurileema
  32. What are the bundles of Neuron processes within the CNS called?
  33. What are the bundles of Neuron processes within the PNS called?
  34. Dendrites
    • Short branching extensions that act as a receptor for incoming inforation and convey info toward cell body
    • May contain spiky dendritic spines which are points synapse with other neurons
    • uses graded potential to relay info to cell body
  35. Axon
    A long single process that directs information away from the cell body toward the synaptic terminal (other end of the axon)
  36. A long axon is called
    Nerve fiber
  37. Axon Collaterals
    a branched axon contains terminal branches (telodendria) with axon terminals
  38. The ___1___ generates nerve impulses at the _____2______ along the _____3______ to the _______4_____ where neurotransmitters are secreted into the __________5_________ to excite or inhibit another neuron or some organ or gland.
    • 1. Axon
    • 2.Axon hillock (next to cell body)
    • 3. Axolemma (plasma Membraine)
    • 4. Axon terminal
    • 5. Synaptic cleft (extracelluar space)
  39. What does the Axon lack?
    • Nissl Bodies and the Golgi apparatus
    • and proteins must be made and transported from the cell body through the length of the axon and items for degredation and recycling must be transported back to the cell body
  40. Myelin Sheath
    A whitish fatty segmented covering that protects nerve fibers (axons) and electrically insulates the fiber to speed up nerve impulses
  41. Regions of the brain and spinal cord that contain dense collections of myelinated fibers are referred to as
    White Matter
  42. Regions of unmyelinated fibers are referred to as
    Grey Matter
  43. Which propagate impulses faster Myelinated or Unmyelinated fibers?
    Myelinated Fibers
  44. The sheath cells wrap around the axon the exposed portion is called the............
  45. Nodes of Ranvier
    • One sheath cell does not connect to its neighbor forming gaps along the axon that are not covered.
    • This is where axon callaterals can emerge and the signal is propagated in leaps rather than small steps
  46. What are the Structural Classifications of Neurons?
    • Mutipolar Neurons
    • Bipolar Neurons
    • Unipolar Neurons
  47. Multipolar Neurons
    • Contains 3 or more processes with only one axon.
    • 99% of all neurons
    • are the major neuron type of the CNS
  48. Bipolar Neurons
    • Contains an axon and a dendrite that extend from opposite sides of the cell body
    • Located in the optic and olfactory areas
  49. Unipolar Neurons
    • A single process that divides into a distal and proximal branch where the distal branch is normally associated with a sensory receptor (peripheral process) and the central process entering the CNS
    • should be considered as a single long axon that propagates info to the CNS
  50. What are the Functional Classifications of Neurons?
    • Sensory
    • Interneurons
    • Motor
  51. Sensory
    • (Afferent) receives sensory stimuli and propagates that info to the CNS
    • unipolar with sensory ganglia outside the CNS
  52. Interneurons
    • (Association Neurons) Receives info from sensory Neurons, Processes that info, Makes a decision which it propagates to motor neurons.
    • Multipolar Neurons residing within the CNS
  53. Motor
    • (Efferent) receives info on the decision and responds (usually by inhibiting or exciting a musccle group)
    • Multipolar with cell bodies located within the CNS
  54. A Nerve Impulse
    Or Action Potential is an electrical impulse that is generated in and conducted through the length of the axon
  55. Potential energy
    energy that is stored, that has the potential to do work
  56. Electrial potential
    for cells- the charge difference across the cell membraine
  57. Potential Difference
    • is the difference in charges separated by some device (semipermeable membrane)
    • The greater the potential difference the higher the Voltage
  58. Kinetic Energy
    • when work is done and the potential is relieved, the charge difference is increased or decreased
    • (in motion)
  59. Voltage
    Is the energy generated by a separation of charges
  60. Current
    Is the flow of electrical charge (electrons or ions) from one point to another for the purpose of doing work
  61. Resistance
    Is the opposition to flow of electrons or ions from one point to another that decreases the current and is determined by the material for which current passes through
  62. Insulator
    • is a poor electrical conductor
    • rubber, plastic, plasma membrane
  63. Conductor
    • Is a good electrical conductor
    • Metal, water, Open ion channels
  64. Ohm's Law
  65. Ion Channels
    Proteins, Nucleic acids and potassium within the cell to give the inside of the cell a net negative charge in respect to the more positive, sodium- dominated extracellular fluid
  66. Ion Channels can _________1_________a potentialdifference across the________2________.
    • 1. Increase or decrease
    • 2. Membrane
  67. What are the ion channels?
    • Leakage
    • Ligand-gated
    • Voltage-gated
    • Mechanically-gated
    • These channels within the membrane are selective for a particular ion to pass and may allow these ions to pass only under certain circumstances.
  68. Leakage Channels
    are always open (not gated or closeable)
  69. Ligand-Gated Channels
    open when a chemical stimulus binds to the channel, otherwise it remains closed
  70. Voltage-Gated Channels
    Open and close in respones to changes in the Membrane Potential
  71. Mechanically-Gated channels
    Open in respone to physical deformation of the receptor
  72. Ion Channels allow substances to cross the membrane when open to follow their _______________________________ and prevent transport of those ions when closed.
    Electrochemical Gradient
  73. Electrical Gradient
    is the desire of positive and negative to attract one to one another
  74. Chemical Gradient
    is the desire of an equilibrium of chemicals such that a high concentration of a substance moves to an area of lower solute concentration following its own Kinetic energy