Anatomy chap. 13 nervous system

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Anatomy chap. 13 nervous system
2010-10-08 18:24:25

Nervous system
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  1. What are the two anatomical subdivisons of the nervous system?
    • Central nervous system
    • Peripheral nervous system
  2. What body cavity does the CNS belong to?
    Dorsal body cavity
  3. What is the function of the CNS?
    • Integration, processing,
    • Interperts incoming sensory information
    • Directs motor responses (both visceral
    • & organs)
    • Seat of higher functions
    • Intelligence, memory, learning
    • Emotion
  4. In early developement how does the CNS begin?
    As a mass of neural tissue organizing into hollow tubes
  5. What is the PNS?
    All neural tissue outside the CNS
  6. What is the funciton of the PNS?
    • Communication link with the CNS
    • Provides sensory input
    • Carries motor output
  7. How does the PNS create a link with the CNS?
    Nerves extend to/from brain & spinal cord
  8. In the PNS where do the cranial nerves connect?
    To & from brain
  9. In the PNS where do the spinal nerves connect?
    To & from the spinal cord
  10. What are the two different types of cranial and spinal nerve fibers?
    • Afferent
    • Efferent
  11. Afferent and Efferent are what type of anatomical division?
    Functional divisons
  12. Where does the afferent division of the PNS begin?
    Begins at receptors
  13. Where does the efferent division of the PNS begin?
    Begins inside the CNS
  14. What does afferent mean?
  15. What does efferent mean?
  16. What is the function of the afferent nerve fiber?
    Brings information to the CNS
  17. What is the function of the efferent nerve fiber?
    Carry motor commands from the CNS to the body
  18. What type of nerve fibers are afferent?
    Sensory nerves
  19. What type of nerve fibers are efferent?
    Motor nerves
  20. Give examples of efferent nerve fibers.
    • Muscle cell
    • Gland cell
  21. What are the efferent nerve fibers specialized to do?
    Perform specific functions
  22. Give examples of receptors.
    • May be a dendrite, specialized cell or cluster of cells
    • Or a complex sense organ
  23. Name the two components of the afferent and efferent divisions?
    Somatic & visceral
  24. What does the somatic component monitor?
    • Skeletal muscles, joints & the skin
    • Voluntary of Involuntary
  25. What does the visceral compontent control?
    • Smooth muscle, cardiac muscle, glands
    • Ventral body cavity system
    • ANS outside awareness of control
    • Homeostasis
  26. What is neural tissue? What are two basic cell types?
    • Nervous tissue
    • Neurons
    • Neuroglia
  27. What is the function of neural tissue?
    • Specialized for the conduction of electrical impluses from one
    • Region of the body to another sends signals that are
    • Rapid, specific and usually cause immediate response
  28. What is another name for the perikaryon?
    • Cell body
    • Or Soma
  29. Describe the characteristics of the cell body?
    • Usually has several branching dendrites, is attached to an
    • Elongated axon that ends at one or more synaptic terminal
  30. What is the does the cell body contain?
    • Organelles responsible for energy production & biosynthesis
    • Of organic molecules such as enzymes
  31. The nerve cell neuron is highly specialized, what funciton can it perform as a result of this?
    Transfer & process information
  32. What is the function of the neurons?
    Transmit the electrical impulse along their cell membrane
  33. What kind of cell is a neuron (not nerve cell)?
    • Excitable cells
    • Highly specialized
  34. What is the longest cell in the body? How long?
    • Neurons
    • 1 meter
  35. Why do neurons have longevity?
    • It cannot divide or repair
    • Lacks centrioles and centrosomes
  36. Define glial?
    • Glue
    • Supporting
  37. Name the neuroglial cells of the CNS.
    • Astrocytes
    • Oligodendrocytes
  38. What are the functions of neuroglial cells?
    • Supporting framework for neural tissue
    • Provides nutrients to neurons
    • Isolate and protect neurons
  39. How many neuroglial cells are their?
    5 times as many as neurons
  40. What are the neuroglial cells capable of that the neurons are not?
    Can divide and repair
  41. How many types of glial cells are in the CNS?
    4 types
  42. How many types of glial cells are in the PNS?
    2 types
  43. What makes the neural tissue of the CNS different from the PNS?
    Glial cells
  44. When a stimulus is received it can only move one direction, why?
    Because of the chemical synapse
  45. What are astrocytes known as?
    Star cells
  46. What is the function of the astrocytes?
    • Shield neurons from direct contact with other neurons & fluid
    • Maintain blood-brain barrier
    • Structural repairs
    • Absorbs and recycles neurotransmitters
  47. What is the astrocyte feet?
    Process of the astrocyte.
  48. What is the function of the astrocyte feet?
    Contacts the surface & covers most of the surface of capillaries within the CNS
  49. What significantly increases the suface area of the astrocyte?
    A large number of cytoplasmic processes
  50. How does the increase of surface area of the astrocyte control the interstitial environment?
    • By facilitating the exchange of ions and
    • Other molecules within the extracellular fluid
    • Within the CNS
  51. What is the frame work of astrocytes?
    Packed with microfilaments that extend across the breadth of the cell.
  52. How does the astrocyte support the brain & spinal cord?
    By forming a structural framework
  53. What is essential for maintaining the blood-brain barrier?
    Chemical secretions of the astrocyte
  54. What are neurotropic factors?
    • Secreted astrocyte chemicals involved in directing growth &
    • Interconnection of developing neurons
  55. Define oligo?
  56. What is the function of the oligodendrocytes?
    Myelinate CNS axons
  57. How does myelin improve the functional performance of neurons?
    Myelin helps prevent the electrical current from leaving the axon
  58. Define internodes?
    Large area wrapped in myelin
  59. What are nodes of ravier? How are they produced?
    • Gaps between the myelin sheaths
    • Produced by adjacent oligodendrocytes
  60. What is another name for myelin sheaths?
    Nodes of Ravier
  61. What is the area called white matter? Why does it appear white?
    • Regions dominated by myelinated axons of the CNS
    • Lipids
  62. What is the area of gray matter? What makes it gray?
    • Regions dominated by neuron cell bodies, dendrites, & unmyelinated axons
    • Ribosomes
  63. What are the microglia in the CNS?
    Phagocytic cells
  64. In times of infection or injury what glial cells increase dramatically in the CNS?
  65. Describe microglial cells?
    Smallest glial cells, posess slender cytoplasmic processes with many fine branches
  66. How are microglial cells developed?
    Appear early in embroynic development through the division of mesodermal stem cells
  67. Describe ependymal cells?
    • Cubodial to columnar in form. Unlike typical epithelial cell axon
    • They have a slender process that branch extensively, making direct
    • Contact with glial cells in surrounding neural tissue
  68. What is the ependyma?
    A thin epithelial membrane(made up of ependymal cells) that lines ventricles or the brain, central canal of the spinal cord. A type of neuroglial
  69. What do the ciliated ependymal cells assist with?
    Circulation of the cerebrospinal fluid
  70. What do the ependymal cells secrete?
    Cerebrospinal fluid
  71. Where is the neuroglial of the PNS appear?
    Outside brian and spinal cord
  72. What is a collection of nerve bodies in the PNS?
  73. Where are satellite cells located?
    They surround neuron cell bodies within ganglia
  74. What is the function of satellite cells?
    • Insulate the neuron from other stimuli
    • Regulate the exchange of nutrients & wastes with extracellular fluid
  75. Every cell in the PNS is covered by what?
    Schwann cell
  76. What does the schwann cell aid in?
    Regrowth of damaged axons
  77. What is the neurolemma?
    The superficial cytoplasmic covering of schwann cells
  78. What does the perikaryon contain?
    • Organelles that provide energy and perform biosynthetic activities.
    • Neurons, mitochondria, free & fixed ribosomes & membranes of the
    • Rough endoplasmic reticulum
  79. Where does the nerve impulse begin?
    The axon hillock
  80. What do neurons lack?
  81. Because the neuron lack centrioles what does that result in?
    An inability to divide
  82. What are neurofibrils?
    Bundles of neurofilaments. Cytoskeleton elements that extend into the dendrites and axon
  83. What does the cytoskeleton of the perikaryon contain?
    Neurofilaments & neurotubules
  84. What are nissl bodies?
    Ribosomal clusters
  85. What is another name for nissl bodies?
    Chromatophilic substance
  86. How is the action potential generated?
    • At the axon when it is exposed to appropiate stimuli, producing a localized change in the
    • Transmembrane potential
  87. What is the transmembrane potential?
    A property resulting from the equal distribution of ions across the neurilemma
  88. Define axon?
    A long cytoplasmic process capable of propagating an action potential
  89. Where is the axon hillock?
    A special region in the multipolar neuron that connects the initial segments of the axon to the soma
  90. What is the axoplasm?
    Cytoplasm of the axon
  91. What does the axoplasm contain?
    • Neurofibrils, neurotubules, numerous small vesicles, lysosomes, mitochondria and various
    • Enzymes
  92. What is the side branching of an axon called?
  93. Define telodendria
    • Telo=end
    • dendria=tree
  94. What are the terminal arborizations?
    • The main trunk & the collateral end
    • In a series of fine terminal extentions
  95. Where does the terminal arborization end?
    At the synaptic terminal
  96. What is the synaptic terminal?
    • Where the neuron contacts another neuron or effector
    • Part of the synapse
  97. Describe axoplasmic transport?
    Movement of organelles, nutrients, synthesized molecules & waste products between the cell body and synaptic terminals. Complex process. Consumes energy & relies on movement along the neurofibrils of the axon and it's branches
  98. What is the synapse?
    Specialized site where the neuron comminicates with another cell
  99. Where is the terminal bouton found?
    Where one neuron synapses on another
  100. What is another name for the terminal bouton?
    Synaptic knob
  101. What is the function of the glial cells?
    To limit the number & type of stimuli
  102. Name the four structural classifications of neurons?
    • Anaxonic
    • Bipolar
    • Pseudounipolar
    • Multipolar
  103. What are anaxonic? Where are they found?
    • Small, cannot distinguish from dendrites
    • Only found in CNS and in special sense organs
  104. What does bipolar neurons contain?
    A number of fine dendrites that fuse to form a single dendrite. Cell body lies between this dendrite & a single axon. Relatively rare
  105. What important role do bipolar neurons play? Are their axons myelinated?
    • Relaying sensory information concerning sight, smell, & hearing
    • Axons are not myelinated
  106. What does the pseudounipolar look like? Is it myelinated? What type of neurons are these?
    • Continious dendrite & axonal processes & cell body lies off to one side. The initial segment lies at the base of the dendrite branches. May be myelinated
    • Usually sensory neurons
  107. What is the most common neuron in the CNS?
  108. Describe a multipolar neuron?
    All motor neurons that control skeletal muscles. Myelinated axons. Several dendrites & a single axon that may have one or more branches.
  109. What are pre-ganglionic fibers?
    Axons extending from the CNS to a ganglion
  110. What are post ganglionic fibers?
    Axons connecting the ganglion cells with the peripheral effectors
  111. What are afferent fibers? Where are they found?
    Axons of sensory neurons. Extend between sensory receptor and the spinal cord or brain
  112. Name the three catagories of receptors.
    • Exteroceptors
    • Proprioceptors
    • Interoceptors
  113. Name the three functional classifications of neurons. Which system do they belong to?
    • Sensory (PNS)
    • Interneurons (CNS)
    • Motor (PNS)
  114. What is the function of the sensory neurons?
    Transmits impulses from sensory receptors to CNS using afferent fibers
  115. What forms the two afferent divisions of the PNS?
    • Somatic
    • Visceral
  116. What does the somatic division of the PNS deliver?
    • Information about the outside world and our position in it
    • Consciously controlled
  117. What organs belong in the somatic division?
    Muscles, joints, skin, sense organs
  118. What does the visceral division of the PNS deliver?
    Information on internal conditions & status of other organs
  119. What organs belong to the visceral division of the PNS?
    Smooth muscle, cardiac muscle, organs, glands
  120. What is the function of interneurons? Where are they located?
    • Analysis of sensory inputs & coordination or motor outputs
    • Within the CNS
    • May be between the sensory & motor neurons
  121. What neurons account for 99% of the body?
  122. Most interneurons are structurally what type of neuron?
  123. Finish this sentence, the more complex the given stimulus...
    The greater the number of interneurons involved
  124. What is the function of motor neurons?
    Carry impulses away from the CNS to stimulate or modify the activity of a peripheral tissue or organ
  125. What type of fibers are the motor neurons?
    Efferent fibers
  126. What is the efferent somatic division (SNS) responsible for?
    Innervate skeletal muscles consciously controlled
  127. What is the efferent visceral division responsible for?
    • Autonomic(ANS)
    • Effects organs, tissues, other muscles
    • Little conscious control
  128. What two properties of an axon determines the rate of impluse conduction?
    • The presences or absence of a myelin sheath
    • The diameter of the axon
  129. What results in a change in the resting membrance potential?
    Ion movement
  130. How does the action potential develope?
    After the plasmalemma is stimulated to a level known as threshold. Once threshold has been reached, the membrane permability to sodium & potassium ions changes
  131. Define excitiability.
    Ability of cell membrane (plasmalemma) to conduct electrical impulses
  132. Define nerve impulse.
    Propagation of action potentials
  133. What is a vesicular synapses?
    Chemical synapse
  134. All somatic neuromuscular synapses utilize what?
  135. What is the synaptic communication?
    Neuroeffector junction where axon interacts with another neuron, muscle or gland
  136. What is the process of chemical synapses?
    • Action potential arrives at end of presynaptic axon
    • Synaptic vesicles release neurotransmitter
    • Neurotransmitter diffuses across synaptic cleft
    • Neurotransmitters bind to postsynaptic membrane receptors
    • Effects channels in postsynaptic membrane (close or open)
    • Result=stimulation or inhibition
    • Neurotransmitters are broken down by enzymes or transported back into presynaptic terminal.
  137. What is present in the electrical synapses?(non-vesicular)
    Gap junctions between the CNS & PNS neurons
  138. In chemical synapses communication is which direction?
    Only one way from presynaptic to postsynaptic
  139. In electrical synapses communication is which direction?
    Can convey nerve impulses in either direction
  140. What are neuronal pools?
    • Organized interneurons into smaller numbers
    • Group of neurons with specific functions
    • Defined by function soley
  141. How many neurotransmitters are their?
    Over 50