Neuro Final

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Neuro Final
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2014-05-04 19:54:36
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  1. Oligodendrites affect which cranial nerves?

    what diseases goes with this
    I and II

    MS
  2. Cranial nerve fibers that innervate muscles of
    head and neck are lower motor neurons
    • III,
    • VII,
    • IX,
    • XII
  3. Sensory
    cell bodies are outside of brainstem in...
    ganglia
  4. Motor cell bodies are in...
    • brainstem
    • in nuclei
  5. Cranial nerve I: Olfactory
    Sensory

    Lesion causes inability to smell
  6. Cranial Nerve II: Optic
    Sensory

    • Complete
    • lesion of optic nerve results in ipsilateral blindness, loss of pupillary light
    • reflex. Lesions in other parts of pathway can cause blindness
  7. Cranial nerves III, IV, VI: Oculomotor, trochlear, abducens
    • Primarily motor, innervate the six extraocular
    • muscles that move eye and control reflexive constriction of pupil
  8. Complete
    lesion of oculomotor
    ptosis (drooping of eyelid)

    • ipsilateral eye to look outward and down because lateral rectus and superior
    • oblique muscles are unopposed,

    diplopia (double vision) caused by difference in position of eyes

     deficits moving ipsilateral eye medially, downward, upward,

    • loss of pupillary reflex and consensual response to light, loss of constriction of pupil when focusing on
    • near object.
  9. A lesion of the trochlear
    • ipsilateral
    • eye can’t look down and in
  10. Lesion
    of abducens
    • adducted pupil because lateral rectus is
    • paralyzed. Can’t abduct their eye and have double vision.
  11. Cranial nerve V: Trigeminal
    Mixed sensory and motor.

    • Three branches
    • ophthalmic, maxillary, mandibular. All three convey sensory from face and
    • TMJ.  Mandibular has motor axons to
    • mastication muscles.
  12. Trigeminal
    nerve is involved in reflexes
    afferent limb of corneal (blink) reflex

    Masseter reflex: downward tap to chin monosynaptic stretch reflex closes jaw.
  13. Cranial Nerve VII: Facial
    Mixed sensory and motor

    • Sensory fibers transmit touch, pain, pressure info from tongue, pharynx, skin near ear
    • canal

    • Facial
    • innervates muscles that close the eyes, move the lips, produce facial
    • expression.
  14. Facial reflexes
    efferent limb of corneal reflex
  15. Cranial Nerve VIII: Vestibulocochlear
    Sensory, two branches

    Vestibular branch transmits info about head position and movement.

    Cochlear branch transmits info about hearing
  16. Cranial nerve IX: Glossopharyngeal
    Mixed sensory and motor

    Sensory fibers convey somatosensory information from soft palate and pharynx which provides afferent limb of gag reflex and swallowing reflexes

    Motor component innervates pharyngeal muscle and parotid salivary gland. Gag reflex
  17. Cranial Nerve X:Vagus
    Provides afferent and efferent innervations of larynx, pharynx, viscera
  18. Lesion Vagus Nerve
    • Complete lesion results in difficulty speaking,
    • swallowing, poor digestion due to decreased digestive enzymes and decreased
    • peristalsis, asymmetric elevation of palate, hoarseness.
  19. Cranial
    nerve XI: Accessory
    Motor to traps and SCM

    • UMN lesions cause paresis because cortical innervations is bilateral and muscles
    • become hypertonic rather than hypotonic
  20. Cranial Nerve XII: hypoglossal
    Motor innervates intrinsic and extrinsics of ipsilateral tongue

    • Damage
    • causes ipsilateral tongue atrophy, when tongue is out will go ipsilaterally
  21. Basal Ganglia
    • Caudate
    • Putamen
    • Globus Pallidus
    • Subthalamic nucleus
    • Sustantia nigra
  22. Caudate
    • in cerebrum
    • Assumes C shape in development, adjacent to lateral ventricle
  23. Putamen
    in cerebrum
  24. lentiform nucleus
    globus pallidus and putamen
  25. striatum
    caudate and putamen
  26. Globus pallidus
    in cerebrum
  27. Subthalmic nucleus
    inferior to thalamus, lateral to hypothalamus
  28. Substantia nigra
    • in midbrain
    • named for color of cells,
    • some have melanin appear black
  29. Cerebellum
    Coordinates movement and postural control

    • Damage doesn’t interfere with sensation or
    • muscle strength, just coordination and postural control
  30. Functional Regions of the
    Cerebellum
    Vestibulocerebellum

    Spinocerebellum

    Cerebrocerebellum
  31. Cerebrocerebellum
    Are the lateral hemispheres

    Coordinates fine distal limb voluntary movement

    •          
    • Functions of Cerebrocerebellum and dentate include coordination of voluntary movements,
    • planning of movements, and timing.

    Lesions have little effect on posture.
  32. Spinocerebellum (Functional name for vermis and paravermal)
    Somatosensory info

    Coordinates limb movements

    Lesions result in gait and stance ataxia
  33. Vestibulocerebellum ( functional name for the flocculonodular lobe )
    • a lot of info it processes is from vestibular
    • apparatus

    regulates equilibrium

    •             i.     
    • Also
    • receives info from visual areas of brain. Via connections with vestibular
    • nuclei, influences eye movements and postural muscles.

    • Lesions result in
    • truncal ataxia.
  34. Three
    Fundamental Types of movement
    Postural

    Ambulatory

    Reaching/grasping
  35. 2 types of afferent enter cerebellar cortex
    Mossy  fibers

    climbing fibers
  36. mossy fibers
    • Convey
    • somatosensory, arousal , equilibrium, and cortex motor information to
    • cerebellum
  37. climbing fibers
    • Convey
    • information regarding movement errors to cerebellum to Purkinje cells
  38. cerebrum consists of...
    Consists of diencephalon and cerebral hemispheres
  39. Thalamus
    collection of bilaterally located nuclei

    regulates activity level of cortical neurons
  40. intramedullary lamina
    Y-shaped sheet of white matter divides thalamus into three

    -anterior, medial, lateral
  41. Hypothalamus
    • Essential for survival because integrates
    • behaviors with visceral functions.

    Maintains homeostasis
  42. Epithalamus
    • has pineal gland an endocrine gland innervated
    • by sympathetic fibers, helps regulate circadian rhythm, pituitary, adrenal,
    • parathyroid and islet of langerhans secretions
  43. Subthalamus
    • Superior to substantia nigra, part of basal ganglia circuit so regulates movement,
    • facilitates basal ganglia output
  44. Pyramidal cells
    • apical dendrite towards cortex, several basal dendrites off soma, one axon. Most serve
    • as projection, commissural, association fibers, serve as output cells for
    • cortex
  45. Fusiform cells
    • spindle shaped output cells projecting to
    • thalamus
  46. Stellate (granule) cells
    stay in cortex, serve as interneuron
  47. Broca’s area
    • plans movements of mouth during speech and grammatical aspects of language. Area
    • analogous in opposite hemisphere plans nonverbal communication like emotional
    • gestures and adjusting tone of voice.
  48. Tonic receptors
  49. respond as long as stimulus is maintained i.e.
    stretch receptors in muscles fire whole time muscle is stretched
  50. Phasic receptors
    • adapt to a constant stimulus and stop responding i.e.
    • stretch receptors in muscle only respond briefly to quick stretch. In skin
    • brief response of pressure receptors after putting on watch then stop.
  51. Meissner’s corpuscles
    • sensitive
    • to
    • light touch and vibration
  52. Merkel’s disks
    • sensitive
    • to pressure
  53. Pacinian corpuscles
    touch and vibration
  54. Ruffini’s corpuscles
    stretch of skin
  55. Primary endings (annulospiral endings)
    type Ia afferent wrap around central region of each intrafusual fibers

    •                            i.     
    • phasic is mostly in quick
    • stretch like tendon tap, tonic is sustained during constant stretch, rate of
    • firing is proportional to stretch of spindle, info about velocity and muscle
    • length
  56. Secondary endings (flower-spray endings)
    type II afferents end on nuclear chain fibers next to primary endings

    •                        
    • monitors tonic stretch , info about muscle length
  57. Nuclear bag fibers
    clump of nuclei in central region
  58. Nuclear chain fibers
    nuclei in single file
  59. Physical, electrical and chemical properties of the nervous system are divided into three sections
  60. neurons (nerve cells), glia cells, and stem cells
  61. Axoplasmic Transport
    • 1. Transports substances along an axon at varying speeds, slows with aging and disease
    •  
    • 2.Occurs in two directions

    a. Anterograde: moves substances from soma towards axon

    b. Retrograde: Moves substances from synapse to soma to get recycled or reused
  62. Leak channels
    • 1.allows small number of ions to diffuse at a
    • continuous rate, small channels
  63. Modality-gated channels
    • in sensory neurons, open in response to
    • mechanical forces, temperature changes and chemicals (like inflammatory
    • chemicals with the end result of pain), vibration, stretch, pressure
  64. Ligand-gated channels
    open in response to neurotransmitters binding to the postsynaptic cell membrane, cause local potentials due to flow of charged ions from extracellular to intracellular environments
  65. Voltage-gated channels
    electrical charge opens them, they open in response to changes in electrical potential across membrane, open and close quickly, important to release neurotransmitters and forming action potentials
  66. Electrical Potentials
    • Three types of electrical potentials are needed
    • for information transmission

    a. Resting membrane potential

    b. Local potential

    c. Action potential
  67. Local potentials
    smaller than action potentials and graded, spread passively and peters out unless summate
  68. Local receptor potentials
    occur when peripheral receptors of a sensory neuron are mechanically stimulated. Most are depolarizing and excitatory but some can be hyperpolarizing and inhibitory.
  69. Local synaptic potentials
    • created in motor neurons and interneurons when stimulated by other neurons. Neurotransmitter reaches the
    • postsynaptic membrane and changes the membrane potential. Again the potential
    • can be depolarizing or hyperpolarizing.
  70. Temporal summation
    • when small potential changes
    • within milliseconds of each other add together, one axon gets stimulated so
    • fast doesn’t have time to go back to resting and gets to -55 and action potential
    • occurs
  71. Spatial Summation
    • when receptor or synaptic
    • potentials from different areas of the neuron are added together  (from different spaces)
  72. Absolute refractory
    the membrane won’t respond to stimuli because Na+ channels need a certain amount of time after they close to reopen. No matter what won’t open again. When the cell is still depolarizing and right after the channels have closed(during hyperpolarization)
  73. relative refractory period
    later in the action potential when the membrane is returning to normal and may even be hyperpolarized. The Na+ channels may be able to be activated but need a stronger stimulus to do so.
  74. Guillain-Barré syndrome
    acute inflammation and demyelination of peripheral sensory and motor fibers (Schwann Cells)
  75. Multiple Sclerosis (MS)
    produce antibodies that attack oligodendrocyes (CNS)
  76. Presynaptic terminal
    at end of axon, releases neurotransmitters
  77. Postsynaptic terminal
    receives specific neurotransmitters at receptors
  78. Synaptic cleft
    between presynaptic terminal and postsynaptic terminal
  79. synaptic communication (7 steps)
    1. Action potential arrives at presynaptic terminal

    2. Presynaptic terminal depolarizes which opens voltage-gated calcium channels

    3. Ca2+ rushes into terminal and is released intracellularly which causes the synaptic vesicles with neurotransmitter to go to the release site

    4. Synaptic vesicles fuse with membrane and release neurotransmitter

    5.Neurotransmitter diffuses across the synaptic cleft

    6.Neurotransmitter binds to receptor on postsynaptic cell

    7.The receptor changes shape and one of two things happen

    • a.An ion channel associated with the receptor opens
    •                                                   b.Intracellular messengers associated with the receptor are activated
  80. Where synaptic communication occurs
    • Cell body(axosomatic)
    • Dendrites (axodendritic)- most common
    • Axon (axoaxonic)
  81. Excitatory postsynaptic potential (EPSP
    a local depolarization on the postsynaptic membrane, summation of these can lead to an action potential
  82. Inhibitory postsynaptic potential (IPSP
    is a local hyperpolarization on the postsynaptic membrane, decreases the possibility of an action potential, involves the influx of Cl- into the cell and K+ out of the cell when the postsynaptic ion channels open, which causes a hyperpolarization and can inhibit an action potential.
  83. Presynaptic facilitation
    allows more neurotransmitter to be released by the postsynaptic neuron at the presynaptic terminal. The following events occur:

    • a. Presynaptic neuron releases
    • neurotransmitter that depolarizes the axon terminal of a second neuron.
    • b. Causes a little Ca2+
    • influx into the postsynaptic terminal of the second neuron
    • c. Duration of the action
    • potential is extended in the second neuron
    • d. Causes more Ca2+ to
    • enter the postsynaptic terminal of the second neuron
    • e. Causes more neurotransmitter
    • than usual to come to the membrane and be released
  84. Presynaptic inhibition
    • a. Presynaptic neuron releases
    • neurotransmitter that hyperpolarizes the axon terminal of a second neuron

    • b. Duration of action potential is
    • decreased in the second neuron

    • e. Less Ca2+ is then
    • released and less neurotransmitter is released from the cell
  85. Neuromodulator
    released into extracellular fluid or interstitial fluid and adjust activity of many neurons (modulate the whole environment), act at a distance from synaptic cleft, may eventually bind,  last longer than neurotransmitters but take a little longer to work, act with neurotransmitters, a molecule can act as both a neuromodulator and a neurotransmitter depending on where it is released either at a specific synapse or into extracellular spaces
  86. Neuroplasticity
    Ability of neurons to change their function,chemical profile or structure
  87. Habituation
    a decrease in the response to a repeated, benign stimulus.
  88. PT and Occupational habituation
    techniques and exercises to decrease neural response to stimulus
  89. Tactile defensiveness
    abnormal sensitivity of skin to touch
  90. Experience-dependent plasticity
    learning and memory: persistent, long-lasting changes in strength of synapses between neurons and within neural networks
  91. LTP- Long Term Potentiation
    conversion of silent synapses to active synapses
  92. LTD-Long Term Depression
    • conversion of active synapse to silent by
    • removing AMPA receptors from membrane into cytoplasm
  93. Sprouting
    axonal injury in the periphery

    growth of a new branch of intact axon or regrowth of damaged axons

    types: collateral, regenerative
  94. Collateral Sprouting
    when a denervated target is reinnervated by branches of intact axons from neighboring neurons
  95. Regenerative Sprouting
    when an axon and its target cell has been damaged
  96. ANS
    Regulates organs and vasculature

    • Regulates circulation, respiration, digestion, metabolism, secretions, body temp,
    • reproduction
  97. ANS mechanoreceptors
    pressure(aortic baroreceptors, carotid sinuses, lungs)

     stretch (distention of veins, bladder, intestines)
  98. ANS Chemoreceptors
    chemical concentrations in blood

    • Carotid and aortic
    • bodies(respond to oxygen)

    • Medulla (respond to hydrogen
    • ions and carbon dioxide)
    •      
    • Hypothalamus(blood glucose
    • levels, electrolyte concentration)

    • Stomach, taste buds, olfactory
    • bulbs
  99. ANS Nociceptors
    throughout viscera in walls or arteries(stretch and ischemia)
  100. ANS thermoreceptors
    respond to very small changes in temp of circulating blood

    In hypothalamus

    • Cutaneous respond to external
    • temp changes
  101. Central  regulation of visceral function
    Info entering brainstem synapses in solitary nucleus-> to visceral control areas in pons(respiration) , medulla(HR, respiration, vasoconstriction, vasodilatation) modulatory areas in hypothalamus, thalamus, limbic system
  102. Sympathetic nervous system
    Thoracolumbar outflow: cell bodies of sympathetic preganglionic neurons are in lateral horn of spinal cord T1-L2

    Innervate adrenal medulla
  103. Parasympathetic Nervous system
    Craniosacral outflow: cell bodies in nuclei of brainstem and sacral spinal cord

    Ganglia are separate and located near or in target organs

    Parasympathetic info from brainstem travel in cranial nerves to outlying ganglia
  104. Feedforward
    use of sensory info to prepare for movement
  105. Feedback
    use of sensory info during or after movement to make corrections to ongoing movement or future movements
  106. Motor System
    Voluntary movement is top down

    • Descending UMN tracts send movement info from brain to LMN in spinal cord or to cranial nerve LMNs in brainstem
    •  -Also send to interneurons in spinal cord and brainstem

    Control circuits adjust activity in descending tract, excitation or inhibition of motor neurons

    Sensory info also adjust motor activity in all of CNS
  107. Lower Motor Neurons (LMNs)
    Cell bodies in Ventral Horn, myelinated

    • Alpha motor neurons- large
    • Gamma- medium

    Alpha Gamma Coactivation

    Alpha and gamma motor neuron simultaneous activation

    -Maintains stretch on central region of muscle spindle when muscle contracts
  108. Henneman’s size principle
    Slow twitch muscles activated first then larger alpha motor neurons

    Slow twitch continue to contribute during faster actions as fast twitch unites are recruited
  109. LMN pools
    • groups of cell bodies in spinal cord whose axons project to a single muscle
    •      
    • i.  in ventral horn

    • ii. actions of pools correlate to
    • anatomic position ( medial, lateral, anterior, posterior)
  110. medial pools
    innervate axial and proximal muscles
  111. lateral pools
    innervate distal muscles
  112. anterior pools
    extensors
  113. posterior pools
    flexors
  114. Mononeuropathy
    single nerve, focal dysfunction
  115. Multiple mononeuropathy
    several nerves individually=multifocal which produces random asymmetric presentation of signs, two or more nerves affected commonly in diabetes and vasculitis that cause ischemia to the nerves
  116. Polyneuropathy
    many nerves, symmetric involvement of sensory, motor, and autonomic fibers, progresses distal to proximal is the hallmark
  117. Traumatic Myelinopathy
    Loss of myelin just at site of injury caused by compression or entrapment

    Recovery quickly as area just remyelinates quickly
  118. Traumatic Axonopathy
    Usually result from crushing of nerve due to dislocation or fracture

    •                                             
    • Disrupts axon and wallerian degeneration occurs distal to the lesion

    • Affects all axon sizes so reflexes, somatosensation, motor function are all greatly
    • reduced or absent with muscle atrophy

    Recovery is good because myelin and connective tissue remain intact and serve as a guide and support for regenerating axons to their targets. 1mm/day
  119. Severance
    When nerves are physically divided by excessive stretch or laceration

    Axons and connective tissue are completely disconnected, causes immediate loss of sensation and or muscle paralysis of innervated area

    • Wallerian degeneration starts distal to lesion 3-5 days post injury
    •                                     
    • Nerve function may never return to normal due to poor regeneration
  120. Utricle and Saccule
    Respond to head position relative to gravity and linear acceleration or deceleration
  121. Utricular macula
    Responds most to forward flexion or extension

    Linear acceleration and deceleration
  122. Saccular macula
    Responds when head is moved from a laterally flexed position

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