Neuro Exam 1.4

  1. What are cellular Processes?
  2. Name a cellular process:
    typical motor neuron: Axon
  3. Are axons efferent or afferent in nature?
    efferent; AP moves away from cell body
  4. How many axons are there per cell body?
  5. Where does the axon originate?
    axon hillock which doesn't contain ribosomes
  6. Are axons larger or smaller in diameter than dendrites?
  7. Are axons shorter or longer than dendrites?
  8. Do axons run straight or curvy?
  9. Does the diameter of an axon change throughout its length?
    no, it stays the same length
  10. How long is an axon?
    1mm up to 1 meter
  11. Are axons smooth or rough?
    smooth, no ribosomes
  12. Is there protein synthesis in the axon?
  13. Do axons branch?
    they can, but only once (sometimes there are collateral axons, or branches from the axon)
  14. Where do axons terminate?
    distally, forming telodendria
  15. Telodendria:
    specialized structure that facilitates transmission of AP to adjacent neurons (where axon splits and branches)
  16. Buton:
    small, rounded swelling on the ends of telodendria (button-like structure)
  17. What is contained in the buton of the telodendria?
    presynaptic membrane of a synapse
  18. What is a synapse?
    point at which two neurons communicate
  19. What are the four types of postsynaptic membrane?
    • axodendritic
    • axoaxonic
    • axosomatic
    • dendodendritic
  20. axoodendritic:
    axon of one neuron and dendrites of another
  21. axoaxonic:
    axon of one neuron and axon of another
  22. axosomatic:
    axon of one neuron and cell body of another
  23. dendodendritic:
    dendrite of one neuron and dendrite of another
  24. What is contained in an axon?
    • cellular organelles:
    • mitochondria, neurophilaments, neurotubules
    • No ribosomes
  25. Which has spines, axons or dendrites?
  26. Do axons have Nissl bodies?
  27. Are axons myelinated?
    they may or may not be
  28. Are dendrites myelinated?
  29. What is myelin?
    a phospholipid (glycerol and fatty acid)
  30. When does myelination begin?
    4th month of gestation
  31. In the CNS, myelination occurs via:
  32. Can oligodendrocytes myelinate more than one axon?
  33. Do neurons in the CNS have Nodes of Ranvier?
    yes, but not as many as neurons in the PNS
  34. In the PNS, myelination occurs via:
    Schwann cells that wrap around internodes
  35. Internodes:
    insulated segments of myelination that are difficult to depolarize
  36. Nodes of Ranvier:
    non myelinated spaces on the axon
  37. Saltatory conduction:
    when AP comes down the axon, the AP can leap from node ot node, speeding up the AP
  38. Are all axons in the PNS myelinated?
    no, and therefore, those axons don't have saltatory conduction (AP is slower)
  39. What determines the speed of the AP?
    • degree of myelination (or non myelination)
    • diameter of axon
    • -small=slow
    • -large=fast
  40. Are dendrites efferent or afferent?
  41. Are dendrites short or long?
  42. Are dendrites numerous or few?
  43. Are dendrites highly branched?
  44. Are dendrites myelinated?
  45. What do dendrites branch off of?
    cell body
  46. Where are dendrites thicker?
    at origins from cell body
  47. Why do dendrites have dendritic spines?
    increase surface area of neuron and increase potential for synapse
  48. What do dendrites contain?
    • microtubules, microfilaments, and neurofilaments
    • ribosomes (RER)
    • elongated mitochondria
  49. Do dendrites perform protein synthesis?
    yes, because they contain ribosomes
  50. Dendrites conduct action potentials toward:
    the cell body (afferent)
  51. Sensory Neuron:
    • receptor structure (organ)
    • distal process (peripheral)
    • cell body (dorsal root ganglia or ganglia of head and neck for cranial nn)
    • proximal process (central)
    • dorsal horn of spinal cord or sensory nuclei of cranial nn
    • myelination occurs the same as a motor neuron
  52. What is another name for cellular membrane?
    plasma membrane
  53. What does the cellular membrane surround?
    cell body and cellular processes
  54. What is the cellular membrane composed of?
    phosphates and lipids
  55. Is the cellular membrane flexible?
    yes, but not stretchable
  56. How thick is the cellular membrane?
    8-10 nanometers
  57. What type of layers are found in the cellular membrane?
    phospholipid bilayer
  58. How is the phospholipid bilayer organized?
    • phophate on outsides
    • lipid in middle
  59. What is the cellular membrane permeable to?
    • molecules such as fats, steroids, and gases
    • lipid soluble molecules
    • water insoluble molecules (water hating, hydrophobic molecules)
  60. What is the cellular membrane impermeable to?
    • water soluble molecules (hydrophilic molecules, water-loving)
    • ions, sugar molecules, and amino acids
  61. The cellular membrane has selective permeability to:
    certain ions and molecules
  62. What is meant by saying the cellular membrane has selective permeability?
    determines what enters and exits cell
  63. What is meant by saying the cellular membrane is a dynamic structure?
    proteins move and change in quantity
  64. What proteins are embedded in the cellular membrane?
    • receptor sites
    • pores (channels)
    • metabolic pumps: pump things in and out
    • transporter molecules: walk molecules through (i.e., glucose)
  65. What lipids are embedded in the cellular membrane?
    • cholesterol
    • glycolipids
  66. What carbohydrates are embedded in the cellular membrane?
    glycoprotein molecules
  67. Peripheral nn are products of:
    • dorsal and ventral rami of spinal nn
    • cranial nervers are also peripheral nn
  68. How holds together peripheral nn?
    connective tissue
  69. Are peripheral nn motor or sensory?
    • may contain both (mixed) sensory and motor neurons
    • may only contain motor or sensory neurons
  70. What are cutaneous nn?
    those peripheral nerves which only contain sensory neurons since they innervate the skin for general sensations
  71. Why do peripheral nn grossly appear white?
    due to the presence of myelin surrounding individual cellular processes
  72. Are all peripheral nn myelinated?
  73. Microanatomy of a peripheral nerve contains:
    • epineurium
    • fascicles
    • perineurium
    • endoneurium
  74. Epineurium:
    loose areolar connective tissue that surounds the entire nerve
  75. Fascicles:
    bundles of neurons w/in each nerve
  76. Perineurium:
    • surrounds each fascicle
    • provides a barrier to the passage of material into and out of the fascicle
  77. Endoneurium:
    surrounds each neuron in the fascicle
  78. Describe the process of fertilization:
    • egg+sperm=
    • zygote->
    • 2 cells->
    • 4 cells->
    • 8 cells->
    • ball of cells->
    • blastula
  79. What are the initial stages of development?
    • fertilized zygote
    • cleavage due to mitosis
    • morula
    • blastula
    • gastrula
  80. morula
    after 64 cells becomes solid ball of cells
  81. blastula
    ball of cells from morula hollows out
  82. gastrula
    the hollow blastula invaginates and forms the basic germ layers
  83. What are the basic germ layers?
    • ectoderm
    • mesoderm
    • endoderm
  84. What does the ectoderm form?
    nervous system, skin
  85. What does the mesoderm form?
    • blood
    • muscles
    • bones
    • tendons
    • ligaments
    • fascia
    • connective tissue
  86. What does the endoderm form?
    • lining of blood vessels and heart in CV system
    • lymphatic system
    • lining of digestive system
  87. When does the primitive streak occur?
    at 2 weeks
  88. What is included in the primitive streak?
    • ectodermal layer
    • neuroectoderm
    • notochord
  89. What is the neuroectoderm?
    thickening of ectoderm just above dorsal notochord
  90. What does the ectoderm form?
    a neural plate
  91. What does the neural plate become?
    nervous system
  92. What happens at 18 days of gestation?
    • neural plate invaginates along central axis
    • forms beginning of neural tube
    • -neural groove
    • -two neural folds
  93. When is the neural tube fully formed?
    at 23 days gestation
  94. What happens at 23 days of gestation?
    neural folds begin to close and form neural tube
  95. What order does the nueral tube close in?
    • middle
    • superior (rostrally)
    • inferior (caudally)
  96. What does the neural tube become?
  97. Spina bifida:
    failure of the neural tube to close inferior
  98. What do left over cells not incorporated in the neural tube become?
  99. What does the neural crest become?
    PNS (w/ some exceptions)
Card Set
Neuro Exam 1.4
review of neuro lecture 4 for exam 1