neurons (exam4)

  1. what are the 3 distinct segments of neurons?
    • 1.cell body or perikaryon
    • 2.dentrites
    • 3.axon
    • (dentrites and axon are collectively referred to as processes)
  2. what is the difference between nerve process and nerve fiber?
    • a nerve process is and extension of neuron cell body
    • nerve fiber refers to a process and all surrounding layers
  3. what is a cell body or perikaryon?
    the main ventral portion of the cell
  4. what does a cell body or perikaryon contain?
    it contains most of cytoplasm, nucleus, and "most" typical cell organelles
  5. what does the cell body or perikaryon do? and what does it not have?
    • a. it carries on metabolism for entire cell
    • b. no centrioles-> can not produce mitotic apparatus
  6. what are 2 structures unique to neurons?
    • a. neurofibrils
    • b. nissl bodies or nissl substance
  7. what are neurofibrils?
    small fibrils(filaments) composed of microtubules and intermediate filaments
  8. where are neurofibrils found?
    found in the cell body and extend into the processes
  9. what is the function of neurofibrils?
    they function as an internal skeleton and transport routes
  10. what do nissl bodies or nissl substance appear as?
    they appear as orderly arranged granules in the cell body and dendrites but not axons
  11. what do nissl bodies or nissl substance consist of?
    they consist of rough ER and accumulated product (protein)
  12. what is the condition of nissl bodies or nissl substacnces?
    their conditions change with conditions of the neuron
  13. what happens to nissl substance after neuron damage?
    it disappears
  14. what happens during repair?
    large amounts of nissl substance appear
  15. what is the structural description of dendrites?
    short, thick, highly branched extensions of the cell body-> usually several per neuron
  16. what is the functional description of dendrites? (most important description)
    picks up nerve impulses and carries them to neuron cell body
  17. what is the structural description of an axon?
    a single, thin, long process origination from the "axon hillock" of cell body(conical portion of cell body)
  18. an axon may branch forming what?
    axon collateral
  19. how to axons terminate?
    they terminate in fine filaments->telodendrin
  20. what are on the ends of telodendria that are enlargements? (axon)
    synoptic knobs
  21. what is the functional description of an axon(most important description)?
    carries nerve impulse away from neuron cell body to another neuron or and effector
Card Set
neurons (exam4)
exam4 neurons