A&P Class, Exam #5, Class Questions

  1. What is Tay-Sachs disease?
    Tay-Sachs disease, is an inherited defect in a lysosomal enzyme causing myelin to accumulate, burying neurons in fat.

    The affected child begins to show symptoms by six months of age, gradually losing sight, hearing, and muscle function until death occurs by age four.

    [Excess myelin seriously impairs nervous system functioning.]
  2. What are the two cell types of neural tissue?
    • 1.) Neurons
    • 2.) Neuroglia
  3. What are the two divisions of the nervous system and
    their parts?
    • Central Nervous System (CNS)
    • Consisting of the brain and spinal cord

    • Peripheral Nervous System (PNS)
    • Consisting of the nerves (cranial and spinal nerves) that connect the central nervous system to other body parts
  4. What is the name of the drug that decreases membrane permeability to sodium ions?
  5. What is white matter?
    myelinated cells (axons )
  6. What parts of neurons are myelinated? {T}
    just the axons (not the cell body or dendrites)
  7. What are the 3 classifications of neurons?
    • 1.) Multipolar neurons
    • 2.) Bipolar neurons
    • 3.) Unipolar neurons
  8. True or False: The diameter of the axon effects the
    speed of nerve impulse conduction.
  9. Besides the diameter of the axon, what else effects the
    speed of nerve impulse conduction?
    whether the axon is myelinated or not
  11. What are the three structures shared by all neurons?
    • 1.) Dendrites
    • 2.) A cell body
    • 3.) An axon
  12. When were neural stem cells first discovered?
    neural stem cells were first discovered in the 1980's

    in songbirds - the cells were inferred to exist because the numbers of neurons waxed and waned with the seasons, peaking when the birds learned songs
  14. A group of cell bodies clustered together outside the
    CNS are called?
    the cell bodies of some unipolar neurons

    aggregate in specialized masses of nerve tissue called ganglia

    located outside the brain and spinal cord
  15. Distinguish between the types of activities that somatic
    and autonomic nervous systems control?
    • of the somatic nervous system
    • control skeletal muscle contraction
    • under voluntary (conscious) control

    • of the autonomic nervous system
    • control the cardiac and smooth muscle contraction and secretions of glands
    • under involuntary control
  16. What is IPSP?
    • IPSP
    • Inhibitory postsynaptic potential
    • Graded
    • Hyperpolarized membrane of postsynaptic neuron
    • Action potential of postsynaptic neuron becomes less likely

    • Example:
    • a different neurotransmitter binds other receptors
    • increases membrane permeability to potassium ions
    • these ions diffuse outward, hyperpolarizing the membrane
    • action potential in now less likely to occur

    • Some inhibitory neurotransmitters open chloride channels:
    • in this case
    • if sodium ions enter the cell
    • negative chloride ions are free to follow
    • opposing the depolarization
  17. What is the special capillaries that are covered by the
    ependymal cells called?
    • cover specialized capillaries called choroid plexuses
    • (they associate with the ventricles of the brain, and they help regulate the composition of the cerebrospinal fluid)
  19. True or False: A myelinated axon, a nerve impulse, appears to jump from nod to nod.
  20. A myelinated axon, a nerve impulse, appears to jump from nod to nod. So what are the nods called?
    Nodes of Ranvier
  21. What kind of cell produces a neurilemma? {T}
    Schwann cell
  22. What is a neurilemma? {T}
    • neurilemma (neurilemmalsheath)
    • contain most of the cytoplasm
    • nuclei remain outside the myelin sheath
    • surrounds the myelin sheath
  23. In the central nervous system who makes the myelin? {T}
    oligodendrocytes, produce the myelin in the brain and spinal cord in the CNS
  24. Neuroglia cell that is located in the CNS that is responsible for cleaning up dead tissue? {T}
    microglia, help support neurons and phagocytize bacterial cells and cellular debris
  25. What are three types of channels used?
    • 1.) chemically gated
    • 2.) voltage gated
    • 3.) mechanically gated
  26. What is neuroma?
    a tangled mass of regenerating axons that occurs when there is a gap that exceeds 3 millimeters
  27. What are you at, at resting potential?
    RMP = -70mV
  28. What happens when a voltage along an axon changes to a +30? {T}
    • depolarize
    • if a membrane becomes less negative (more positive) than the resting potential, the membrane is depolarizing
  29. Hyperpolarized is what? {T}
    • …the membrane potential becomes more negative
    • than the resting potential, the membrane is...
  30. There is a time after a nerve has been stimulated than
    even threshold stimulus will not cause another stimulus, what is that called?
    • absolute refractory period
    • …the time when threshold stimulus does not start another action potential
  31. What is the relative refractory period?
    when the membrane reestablishes its resting potential

    even though repolarization is incomplete, a threshold stimulus of high intensity may trigger an impulse

    Time when stronger threshold stimulus can start another action potential
  32. When you speak about a greater intensity of stimulation,
    what are speaking about?
    it doesn't mean a stronger impulse, but more impulses per second
  33. True or False: A damaged CNS nerve could not regenerate as easily as a PNS fiber.
    • True
    • the oligodendrocytes cannot produce the little buds that the Schwann cells can to regenerate an axon
  34. How long does the excitatory postsynaptic potential tend
    to last?
    lasts for about 15 milliseconds
  35. "Cortical Spreading Depression" leads to what?
    to a migraine
  36. Scattered throughout the cytoplasm are many membranous packets of what?
    chromatophilic substance (nissal bodies)
  37. Small cells that have fewer process than other types of
    neuroglia are what?
  38. Where would you find epednamal cells. {T}
    in the inner lining of the central canal and the inside spaces of the brain (ventricles)
  39. What is the most abundant type of CNS neuroglia?
  40. What is the area just distal to the cell body where the
    axon arises from? {T}
    axonal hillock
  41. Around the same area where the axonal hillock is, there
    are structures there for support, what are they? {T}
  42. If axon exits the body and goes one side and the other
    the other way, what is that? {T}
    • collaterals
    • the axon gives off many branches…
  43. What are dendrites? {T}
    • they are on the other end from collaterals
    • typically highly branched
    • they are receiving only
    • tiny, thorn-like spines on their surfaces, which are contact points for other neurons
  44. Besides dendrites, where else might have a synapse
    communicating with an axon?
  45. What type of nerve cell is a Schwann cell and what does
    it do?
    • neuroglia cell
    • that encases the large axons of peripheral neuron in lipid-rich sheets
    • …etc...
  46. What neuron brings an impulse to a synapse?
    the presynaptic neuron
  48. What are satellite cells?
    small, cuboidal cells that surround cell bodies of neuron in ganglia
  49. Distinguish between a sensory receptor and a effector.
    sensory receptors gather information, by detecting changes inside and outside the body

    effectors are outside the nervous system and they include muscles that contract in response to nerve impulse stimulation and glands that secret when stimulated
Card Set
A&P Class, Exam #5, Class Questions
Questions for the test