Nervous System

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Nervous System
2012-06-09 22:01:21
Nervous System

Nerve Cells
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  1. System that is responsible for short-term regulation and immediate control of all the other body systems.
    Nervous System
  2. System responsible for the long-term regulation of the body.
    Endocrine System
  3. Brain and Spinal cord (dorsal cavity)
    CNS - Cental Nervous System
  4. Cranial nerves and spinal nerves (not in the dorsal cavity)
    PNS - Perioheral Nervous System
  5. Sensory information from the receptors to the brain
  6. Motor commands to muscles and glands from the brain
  7. Touch, pain, position, taste, smell, vision, sound and temperature are what type of receptor
    Afferent - Sensory (Input)
  8. Somatic and autonomic are what type of receptor
    Efferent - Motor (Output)
  9. Efferent system's voluntary control of skeletal muscles
    Somatic Nervous System
  10. Efferent systems's involuntary control of smooth muscle, and cardiac muscle and glandular activity
    Autonomic Nervous System
  11. Part of the autonomic nervous system that is "fight of flight"
    Sympathetic Nervous System
  12. Part of the autonomic nervous system that is "rest and digest"
    Parasympathetic Nervous System
  13. Most common neuron in the CNS
    Multipolar neuron
  14. The typical spinal neuron (efferent)
    Multipolar neuron
  15. Neuron that controls skeletal muscle and are interneurons
    Multipolar neuron
  16. Uncommon neuron of the afferent system
    Bipolar neuron
  17. Neuron involved in the senses of sight, smell and hearing
    Bipolar neuron
  18. Neuron in the afferent system involved in the senses of touch, pressure, pain, position and other mechanical stimulus.
    Unipolar neuron
  19. Neuron found in the brain that connects neurons to each other without and axon.
    Anaxonic neuron
  20. An encapsulated receptor found in deep layers of the skin that senses vibratory pressure and touch.
    Pancinian corpuscle
  21. How many types of neuroglial cells are in the CNS
  22. Secrete CSF = cerebral spinal fluid, ciliated cells, line the central canal.CSF cushions and distributes nutrients to the brain and spinal cord.
    Ependymal Cell
  23. Maintains the blood-brain barrier by wrapping around capillaries.
  24. large, most numerous helper cells, also involved in signaling
  25. Create framework of microfilaments or the cytoskeleton of neurons
  26. Repairs tissue, although may not regain normal function
  27. Involved in embryonic development of neural tissue, groups and directs neurons,
  28. Control the environment around neurons of ions, nutrients, recycling neurotransmitters, etc.
  29. myelinate the axons of neurons in the CNS
    • Oligodendrocytes
    • One Oligodendrocyte can wrap several nearby axons,
    • several are needed to wrap sections of axon
  30. gaps in the myelin
    Nodes of Ranvier
  31. “white matter” because of the high amount of lipids in the Oligodendrocyte membrane
    Myelin is “white matter”
  32. Unmyelinated cells are
    • “grey matter”
    • because you can see the neuron’s RER or Nissl bodies.
  33. white blood cell origin, microphages, clean up debris, bacteria, waste materials
  34. How many types of neuroglial cells are found in PNS?
    Two types
  35. regulate the environment like astrocytes in the CNS
    Satellite Cells
  36. myelinates the axon of one axon only, and many are needed towrap an entire axon.
    • Schwann cells
    • can also group or collect axons together, however, these axons are not‘buritto wrapped’ and are therefore unmyelinated axons.
  37. How do Schwann cells respond to injury to the axon?
    by mitosing and forming a cord for the axon to follow.By following the cord of Schwann cells, the axon has a chance of rebuilding and finding its distal end.Axon regeneration is a difficult process to predict. Sometimes the axon can be repaired, sometimes itcan’t.
  38. progressive destruction of myelin sheaths in the CNS and PNS.
  39. diseases include MS and heavy metal toxicities.
    Demyelinating diseases
  40. ‘Grey Matter’ of the brain and cord. Large nucleus and a cytoplasm full of :Mitochondria
    Cell body or Soma.
  41. produce ATPs, to move vesicles, run the Na+/K+ pump
  42. make cell look grey and make neurotransmitter proteins.
    Nissl bodies
  43. Where are chemically gated channels that react to a neurotransmitter found?
    On the cell body and dendrites
  44. highly branched area that receives the information from the other neurons and haschemically gated channels and nearby receptors that bind to the neurotransmitter.
  45. ‘White matter’. Long process with microtubules, vesicles, mitochondria and many enzymes.
  46. may be myelinated by the Oligodendrocyte, little repair is possible.
    The axon in the CNS
  47. may be myelinated by the Schwann cell. Some repair of the axon is possible.
    The axon in the PNS
  48. trigger zone.
    axon hillock
  49. The axon end at ____________ or ____________ which contain vesicles of neurotransmitter
    synaptic terminals or synaptic knobs
  50. has electrically gated channels that react to the action potential
    The axon
  51. specialized site where the synaptic terminal releases the neurotransmitter to communicatewith another cell.
  52. The cell releasing the neurotransmitter is called
    the presynaptic cell
  53. the cell receiving the neurotransmitter is called
    the postsynaptic cell and is a neuron, a muscle fiber, or agland.
  54. Cranial nerves and spinal nerves, (not in the dorsal cavity)
    PNS – peripheral nervous system
  55. Sensory receptors monitor temperature, pressure, touch, sight, smell, hearing,
  56. Sensory receptors monitor position and posture, movement of joints and muscles
  57. Sensory receptors monitor deep pressure and pain in viscera and taste
  58. Motor neurons
    Skeletal muscle – voluntary movement
    Somatic motor neurons
  59. Motor neurons
    Sympathetic and Parasympathetic systems – involuntary control
    Autonomic nervous system
  60. motor neurons that innervate skeletal muscles have a cell body in the CNS and are some ofthe longest multipolar neurons in our body.
    Somatic motor neurons
  61. neurons innervate everything that is not skeletal muscle, ie. smooth muscle, glands, fatcells and the heart.
    Autonomic neurons
  62. function in between other neurons and are in the responsible for the communication and coordination of the nervous systems also responsible for learning, memory andhigher functions that are not well understood.
    • Interneurons
    • There are more interneurons in the body than any othertype of neuron.
  63. resting potential or transmembrane potential of –70 mvolts is maintained by the
    • Na+/ K+ pump
    • It actively pumps 3 Na+ ions out of thecell and 2 K+ ions back into the cell using ATP.
  64. There arechemically gated Na+ channels & chemically gated K+ channels on the
    dendrites & cell body
  65. voltage gated Na+ channels & voltage gated K+ channels on the
  66. The action potential depends on the movement of
    Na + and K+ ions through these chemicallyand voltage gated channels.
  67. Polarized =
  68. Repolarized =
    more negative
  69. Depolarized =
    more positive
  70. Hyperpolarized =
    more negative than -70mvolts
  71. An excitatory neurotransmitter binds to the receptors on the dendrites and cell body and opens the
    chemically gated Na+ channels and Na+ ions enter the cell, depolarizing it toward theshold.
  72. If enough Na+ ions enter the cell to achieve threshold at the axon hillock, the axon’s
    voltage gated Na+ channels open carrying the action potential down the length of the axon triggeringa chain reaction, opening more Na + gates all the way down the axon to the synaptic knobs
  73. After the cell is depolarized, the Na+ channels begin to close and the
    K+ voltage channels open,repolarizing the cell. More K+ ions leave the cell due to the open channels and the cell is brieflyhyperpolarized.
  74. At the synaptic knobs, the action potential causes the release of
    a neurotransmitter
  75. Once a neuron achieves threshold and fires off an action potential, it goes to the synaptic knobs. Thisis called The
    • The All or Nothing Principle
    • The neuron either fires or it doesn’t. (This is true of musclefibers too which also have excitable cell membranes! )
  76. A neuron may reach threshold one of 2 ways:
    One single neuron may fire several times in quick succession, called:
    temporal summation
  77. A neuron may reach threshold one of 2 ways:

    Several neurons may fire together at the same time, which is called:
    spatial summation
  78. A neuron that synapses on another neuron and causes some depolarization (more +) toward thethreshold is said to have produced an
    • excitatory postsynaptic potential, EPSP
    • Several EPSPs arenecessary to bring the neuron to threshold.
  79. A neuron may also synapse on another neuron which inhibits it by causing hyperpolarization(more -) away from threshold. It opens the chemically gated K+ gates which creates a larger gap tothreshold. Such an event is called an
    • inhibitory postsynaptic potential, IPSP
    • inhibited because a larger than normal additional stimulus is required to reachthreshold. The neuron can also become hyperpolarized if the chemically gated Cl- channelsopen, allowing more Cl- into the cell.
  80. An action potential comes down the axon and reaches the
    synaptic knob.
  81. This opens Ca+ ion channels and Ca+ ions flow into the synaptic knob, which allows the excytosis of the vesicles filled with a

    like acetylcholine, ACh.
  82. The neurotransmitter, Ach, binds to the receptors on the post-synaptic membrane and openschemically gated Na+ channels, causing a depolarization of the membrane and a gradedpotential, an
    • Excitatory post-synaptic potential, EPSP
    • If enough EPSPs are received by thepost-synaptic membrane, it will generate an action potential.
  83. The neurotransmitter is released from the receptors and broken down by an enzyme andreabsorbes by the pre-synaptic knob. In the case of acetylcholine that enzyme is
  84. Indirectopening of the channels is done by activating a
    G protein and second messenger system or byactivation an enzyme that opens the gated channels.
  85. an excitatory neurotransmitter for skeletal muscles
  86. actslike acetylcholine at these ‘nicotinic receptors’
  87. block acetylcholinesterase and increase the amount of neurotransmitter at the synapse, causingtremors and death
    Organophosphate insecticides and some nerve gases
  88. blocks acetylcholine’s binding on receptors in the body and can beused as an antidote to the acteylcholinesterase drugs also causes increased heart rate and decreased bronchial secretions for example
  89. blocks acetylcholine atskeletal muscle receptors and causes paralysis
    Curare or succinyl choline
  90. involved in consciousness. It is an important neurotransmitter for the Sympathetic system, or fight and flight system. Norepinephrine is brokendown by Monoamine Oxidase, MAO.
  91. increases the amount of norepinephrine available at the synapse.such as Elavil
    MAO inhibitor
  92. decreases heart rate, blood pressure and has a calming effect. It is also used toreduce ‘stage fright’. It has recently been experimentally used to ‘prevent post-traumatic stresssyndrome’ if given within a short time of the event.
    such as Propranolol
    A beta blocker,
  93. block the re-uptake of norepinephrine and also acts as a transmitter itself so it ishighly stimulatory
    • Amphetamines
    • Clinically amphetamines such as Ritalin are used in hyperactive children
  94. typically excitatory and is linked to an extremely pleasurable feeling in our brain. It isalso responsible for fine movement and coordination
  95. Too much dopamine has been linked to
  96. Too little dopamine is responsible for the muscle rigidity associated with
    Parkinson’s disease
  97. Dopamine is broken down by
    • Monoamine Oxidase, MAO
    • So an MAOinhibitor increases the amount of dopamine available.
  98. an addictive stimulant that blocksthe re-uptake of dopamine and norepinephrine into the pre-synaptic cell
  99. the number of receptors on the cell membranes decreases so that an increased dose is required to have the same effect
    “down regulates”
  100. responsible for our moods, feelings of well-being, appetite and our sleep cycles.
  101. thought to be due to a lack of serotonin
  102. a precursor to serotonin
  103. Prozac
    • seratonin re-uptake inhibitor
    • increase the amount of seratonin available andelevate the mood
  104. Serotonin is broken down by
    • Monoamine Oxidase, MAO
    • So an MAO inhibitor alsoincreases the amount available at the synapse. MAO inhibitors and seratonin re-uptake inhibitorshave the same effect of increasing the amount of serotonin and should not be used together.Serotonin is thought to naturally increase in the neuron with meditation practice
  105. Glycine and GABA are both
    • inhibitory neurotransmitters
    • They open Cl- channels and hyperpolarize the cell
  106. Drugs like valium and barbiturates enhance theeffect of
  107. GABA reduces
  108. involved with the transmission of the sensation of pain
    Substance P
  109. the body’s natural pain reliever, or opiod because they inhibit the action ofSubstance P
    • Endorphins
    • Endorphins bind to specific receptors in the body
  110. drugs from theopium poppy are powerful analgesics that have been used since 4000BC
    bind to many receptors in the body acting likeendorphins. Analgesia, lethargy and constipation are common effects of
  111. stimulates many areas of the CNS at ‘nicotinic’ acetylcholine receptors. It causesincreased heart rate, blood pressure and is a mood-altering drug. Tolerance and addiction arecommon side effects
  112. a commonly used stimulant with a variety of effects. It stimulates the brain, the heart,increases respiration, blood pressure and the amount of Norepinephrine and epinephrine in the body.People develop a tolerance and addiction, however, withdrawal is usually limited to headaches andrestlessness
  113. Summary –drugs and toxins may act in the following ways:
    Morphine binds to endorphin receptors and mimics the effect of natural endorphins.
    Nicotine binds to particular acetylcholine receptors and mimic the effects of natural endorphins
    Receptor activators (agonist)
  114. Summary –drugs and toxins may act in the following ways:
    Atropine blocks acetylcholine receptors in the parasympathetic system. (muscarinic)
    Curare and succinyl choline block acetycholine receptors in skeletal muscle .
    Beta blockers block Norepinephrine at beta receptors. (beta 1, beta 2 receptors)
    Receptor blockers (antagonist)
  115. Summary –drugs and toxins may act in the following ways:
    Amphetamines and Cocaine block Norepinephrine and Dopamine inactivation
    Organophosphate insecticides block acetylchoinesterase
    MAO inhibitor drugs block the breakdown of Norepinephrine, Dopamine and Serotonin
    Serotonin re-uptake inhibitor blocks the removal of serotonin at the synapse
    Block the inactivation of the Neurotransmitter
  116. Summary –drugs and toxins may act in the following ways:
    Tetanus Toxin blocks the release of glycine, which inhibits neurons so muscles contract.
    Botulism Toxin blocks the release of acetylcholine so muscles are unable to contract.
    Block release of the neurotransmitter
  117. binds to endorphin receptors and mimics the effect of natural endorphins.
  118. binds to particular acetylcholine receptors and mimic the effects of natural endorphins
  119. blocks acetylcholine receptors in the parasympathetic system. (muscarinic)
  120. block acetycholine receptors in skeletal muscle.
    Curare and succinyl choline
  121. block Norepinephrine at beta receptors. (beta 1, beta 2 receptors)
    Beta blockers
  122. block Norepinephrine and Dopamine inactivation.
    Amphetamines and Cocaine
  123. block acetylchoinesterase
    Organophosphate insecticides
  124. block the breakdown of Norepinephrine, Dopamine and Serotonin
    MAO inhibitor drugs
  125. blocks the removal of serotonin at the synapse.
    Serotonin re-uptake inhibitor
  126. blocks the release of glycine, which inhibits neurons so muscles contract.
    Tetanus Toxin
  127. blocks the release of acetylcholine so muscles are unable to contract.
    Botulism Toxin