HSII Ch. 8

  1. Central Nervous System (CNS) def.
    brain & spinal cord
  2. Peripheral Nervous System (PNS) def.
    all nerves
  3. Autonomic Nervous System (ANS) def.
    involuntary/automatic functions
  4. PNS divisions
    • autonomic (involuntary motor nerves)
    • somatic (voluntary) motor nerves
    • sensory nerves
    • branial nerves
    • spinal nerves
  5. 3 main parts of a neuron
    • dendrites
    • cell body
    • axon
  6. dendrites def.
    conduct impulses to cell body of a neuron
  7. axons def.
    conduct impulses away from cell body to other neurons
  8. sensory (afferent) neurons def.
    • conduct impulse sto spinal cord & brain
    • ex.: feeling heat from a stove
  9. motor (efferent) neurons
    • impulses away from brain & spinal cord to muscles & glands
    • ex.: moving hand off hot stove
  10. interneurons
    impulses from sensory neurons to motor neurons
  11. glia (neuroglia) function
    • support cells
    • bring cells of nervous tissue together structurally & functionally
  12. main types of glia in CNS
    • astrocytes
    • microglia
    • oligodendrocytes
    • Schwann cells
  13. astrocytes
    • star shaped
    • anchor sm. blood vessels to neurons
  14. microglia
    sm. cells move inflamed brain tissue carrying phagocytes
  15. oligodendrocytes
    from myelin sheaths on axons in the CNS
  16. Schwann cells
    form myelin sheats on axons of the PNS
  17. nerve def.
    bundle of PERIPHERAL axons
  18. tract def.
    bundle of CENTRAL axons
  19. types of tracts
    • white matter
    • gray matter
  20. white matter
    • tissue comp. primarily of myelinated axons
    • can be nerves or tracts
  21. nerve coverings
    fibrous connective tissue
  22. types of nerve coverings
    • endoneurium
    • perineurium
    • epineurium
  23. endoneurium def.
    surrounds indiv. fibers w/in a nerve
  24. perineurium
    surrounds bundle (aka fascicle) of nerve fibers
  25. epineurium
    surrounds entire nervea
  26. reflex arcs def.
    nerve impulses conducted from receptors to effectors over neuron pathways
  27. reflex def.
    contraction by a muscle or secretion by a gland
  28. two-neuron arcs def.
    • simplest reflex
    • consist of sensory neurons connecting in spinal cord w/motor neurons
  29. three-neuron arcs def.
    sensory neurons synapsing in spinal cord w/interneurons that synapse w/motor neurons
Card Set
HSII Ch. 8
nervous system