SCO Neuroanatomey Final

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SCO Neuroanatomey Final
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SCO Neuroanatomy Final
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  1. # Why is the pons refered to as the "bridge"?
  2. * pons means bridge
    * refers to the many transvers fibers that cross the anterior surface of the pons
  3. # Where is the pons located?
  4. * anterior to cerebellum
    • * inferior to midbrain
    • * superior to medulla oblongata
  5. # What structur(es) run through the center and anterior part of the pons?
  6. * basilar groove made from transvers fibers
    * basilar artery that supplies the Circle of Willis
  7. # Which direction do the transverse fibers of the pons travel?
  8. * towards the cerebellum
    * laterally
  9. # What structure connects the brainstem to the cerebellum?
    middle cerebellar peduncles
  10. # Where are the superior cerebellar peduncles locate?
  11. * on posterior side of pons
    • * medial to the middle cerebellar peduncles
    • * only seen if cerebellum is removed
  12. # What are the most posterior structures of the pons not including peduncles in order of medial to latera?
  13. * median sulcus
    • * median eminance
    • * sulcus limitans
    • * vestibular area
  14. # What structure are the facial colliculi expansions of?
    inferior ends of the medial eminences
  15. # Where do the vestibular areas get their name?
    the vestibular nuclei are deep to these structures
  16. # All structures of the posterior pons are the anterior wall of what structure?
    the 4th ventricl of the brain
  17. # What makes up the trapezoid body?
  18. * trapezoid body nuclei
    * cochlear nuclei fibers of the pontine-medullary junction
  19. # Where do the cochlear nuclei fibers of the pontine-medullary junction decussate?
    at the trapezoid body of the pons
  20. # Where is basal part of pons located?
    anterior to the trapezoid body
  21. # What does the basal part of the pons contain?
  22. * pontine nuclei
    • * corticonuclear fibers (synapse elsewhere)
    • * corticospinal fibers (synapse elsewhere)
  23. # What synapses to the pontine nuclei in the pons?
    corticopontine fibers from the cerebral cortex
  24. # Where do the transverse fibers of the pons come from?
    the pontine nuclei of the basal part of the pons
  25. # What is the structure located posteriorly to the trapezoid body of the pons?
    the tegmentum
  26. # What nuclei are located in the tegmentum of the pons?
  27. * vestibular nuclear complexes
    • * facial nucleus
    • * abducens nucleus
    • * spinal nucleus
    • * motor nucleus
  28. # What does the vestubular nuclear complex of the pons receive information from?
    vestibular information from the vestibulocochlear nerve
  29. # How many nuclei make up the vestibular nuclear complexes of the pons, and where in the pons are they located?
  30. * four nuclei (lateral, medial, superior, and inferior)
    * located anterior to the vestibular area of the posterior surface of the pons
  31. # Where is the facial nucleus located in relation to trapezoid bodies? What nerve is it connected to?
  32. * posterior to trapezoid bodies
    * connected to CN VII (the Facial Nerve go figure)
  33. # Where is the abducens nucleus of the pons located?
    the posterior tegmentum
  34. # What do fibers from the facial nerve loop around before synapsing in the facial nucleus?
  35. * the abducens nucleus
    * they do this and form the facial colliculi
  36. # Where is the spinal nucleus of the trigeminal nerve located, and what is its function?
  37. * lateral tegmentum of the pons
    * responsible for pain and temperature sensations
  38. # Where is the motor nucleus of the Trigeminal nerve (CN V) located?
  39. * in the posterior lateral tegmentum of the pons
    * only located in the mid-pons area.
  40. # What are the boundaries of the medulla oblongata?
  41. * superior boundary is pons
    * inferior boundary is spinal cord
  42. # What are the anterior surface structures of the medulla oblongata?
  43. * pyramids
    • * anterior median fissure
    • * decussation of pyramids
  44. # Why are the pyramids of the medulla oblongata named so?
  45. * their shape
    * pyramidal fibers from primary motor cortex travel through here
  46. # What is the main structure of the superior lateral surface of the medulla oblongata?
    olives
  47. # What do the olives of the medulla oblongata contain?
    olivary nuclei
  48. # What is the function of the olivary nuclei of the medulla oblongata?
    accessory pathway of motor control
  49. # What are the posterior structures of the medulla oblongata? (does not line 4th ventricle)
  50. * vagal triangle
    • * hypoglossal triagle
    • * gracile tubercles
    • * cuneate tubercles
    • * posterior median sulcus
  51. # What does the posterior median sulcus of the medulla oblongata separate?
    the two gracile tubercles
  52. # Where are the two cuneate tubercles located?
    lateral to the superior parts of the gracile tubercles
  53. # What is the function of the gracile and cuneate nuclei?
  54. * part of sensory pathways
    • * sensory nerves synaps on nuclei here
    • * project fibers up to the thalamus
  55. # What nucleus of the pons also travels through the medulla oblongata?
    the spinal nucleus of the trigeminal nerve (CN V)
  56. # Where does the spinal nucleus of the trigeminal nerve run in the medulla?
  57. * posterior-lateral
    * continuous with the substantia gelatinosa of the spinal cord gray matter
  58. # What is the function of the external, or accessory, cuneate nucleus?
    sends information into the cerebellum
  59. # What three types of olivary nuclei are there?
  60. * main inferior...
    • * dorsal...
    • * medial accessory...
  61. # What is the function of the olivary nuclei of the medulla?
    send decussating fibers of voluntary movement to the verebellum through inferior cerebellar peduncles
  62. # What nuclei run the length of the medulla oblongata?
  63. * nucleus ambiguus
    • * solitary tract nucleus
    • * dorsal nucleus of the vagus
    • * hypoglossal nucleus
  64. # What is the function of the nucleus ambiguus of the medulla oblongata and what nerves connect to it?
  65. * control muscles of the throat
    * CN IX (glosopharyngeal), X (vagus), and cranial root of XI (accessory)
  66. # What type of sensation does the solitary tract nucleus receive?
    visceral
  67. # Where does the solitary tract nucleus receive information?
  68. * taste from CN VII (facial), IX (glossopharyngeal), and X (vagus)
    • * baroreceptors in carotid sinus
    • * chemoreceptors in the carotid body
  69. # What is the function of the dorsal nucleus of the vagus (CN X)?
  70. * control parasympathetic functions of the vagus nerve throughout body
    * receives info from solitary tract nucleus
  71. # What is the function of the hypoglossal nucleus?
    motor nucleus of the hypoglossal nerve (CN XII)
  72. # What is the vestibolonuclear complex of the medulla oblongata?
  73. * pontine medullary junction
    * deals with vestibulocochlear nerve (CN XIII)
  74. # What is the function of the anterior and posterior cochlear nuclei of the medulla oblongata?
    receive hearing information from the vestibulocochlear nerve
  75. What is the function of the cerebellum?
    • integrates proprioceptive info with balance and sight info
    • sends inhibitory signals to the nuclei of origin of spinal cord and motor complex
    • this fine tunes muscle movements
  76. What type of movement does the cerebellum help with?
    learned motor movement
  77. What structure separates the cerebellar hemispheres?
    the vermis
  78. What are the three lobes of the cerebellum? (one on each side)
    • anterior
    • middle
    • flocculonodular
  79. What structure separates the anterior lobe and the middle lobe of the cerebellum?
    the primary fissure
  80. What structure divides the middle lobe from the flocculonodular lobe of the cerebellum?
    postereolateral fissure
  81. What is the function of the horizontal fissure of the cerebellum?
    • no real function
    • separates the superior and inferior portions of the cerebellum
  82. What connects the cerebellum to the posterior brainstem?
    • superior
    • middle
    • inferior cerebellar peduncles
  83. What type of fibers is are the middle cerebellar peduncles mostly made of?
    • afferent fibers
    • travels from pons
  84. What type of fibers mostly make up the inferior cerebellar peduncles?
    • mostly afferent
    • travel from pons, medulla oblongata, and spinal cord
  85. What type of fibers make up the superior cerebellar peduncles?
    • efferent!
    • travel to midbrain and thalamus regions
  86. What is the name of the internal white matter in the cerebellum?
    arbor vitae (tree of life)
  87. What layers make up the cerebellar cortex organization?
    • Molecular layer
    • Purkinje cell layer
    • Granular layer
  88. What makes up the molecular layer of the cerebellar cortex?
    • basket cells
    • tengential processes of granular cells
    • dendritic tree of the Purkinje cells
    • stellate cells
  89. What is the function of the basket cells of the molecular layer of the cerebellar cortex?
    • connect purkinje cells
    • isolate firing of the purkinje cells through inhibiting surrounding purkinje cells
  90. What makes up the Purkinje cell layer of the cerebellar cortex?
    soma, or cell bodies, of the Purkinje cells
  91. What type of neuron are Purkinje cells?
    Golgi type I
  92. What do purkinje cell axons synapse to?
    intercerebellar nuclei in the deep white matter
  93. What makes up the Granular layer of the cerebellar cortex?
    • granular cells' soma
    • Golgi cells
  94. Where do granular cell axons travel?
    • to the molecular layer of the cerebellar cortex
    • they then split into parallel processes
    • these run parallel to the cortex
  95. What is the function of Golgi cells in granular layer of the cerebellar cortex?
    inhibitory interneurons that inhibit cells in the granular layer
  96. What type of feedback loop do golgi cells of the granular layer of the cerebellar cortex uses?
    negative feedback loop
  97. What type of fibers bring afferent info to the cerebellum, usually through inferior and middle cerebellar peduncles?
    • climbing fibers
    • mossy fibers
  98. Where do climbing fibers of the cerebellum come from?
    olivary nuclei of the medulla oblongata
  99. What do the climbing fibers synapse with, and what kind of reaction do they create?
    • purkinje cell dendrites
    • direcet excitatory influence
  100. Where do mossy fibers of the cerebellar cortex come from?
    all other inputs to the cerebellum
  101. What is the function of mossy fibers in the cerebellar cortex?
    • synapse with excitatory granular cells
    • synapse with inhibitory Golgi cells
    • prevent granular cells from gettin gtoo excited (overstimulated)
  102. What type of effect do the granular cells have on purkinje cells?
    excitatory
  103. What cells make up efferent fibers of the cerebellum?
    purkinje cells
  104. How do purkinje cells interact with with granular cells?
    • with the parallel processes of granular cells
    • 200,000 times per Purkinje cell
  105. Where do purkinje cells synapse?
    • cerebellar nuclei
    • some from flocculonodular lobe exit cerebellum directly
  106. What is Hypotonia?
    • lack of resistance to pressure and motion
    • muscle fibers lose definition
  107. What is posture problem caused by cerebellum?
    stiff legs and shoulders on one side of lesion
  108. What is ataxia?
    tremors when trying to do fine movements
  109. What is dysdiadochokinesia?
    inability to perform alternating movements with regularity and repetition
  110. What are reflex disturbances?
    reflex movements are much larger and continue for a much longer period than usual
  111. What is Nystagmus?
    • "dancing of the eyes"
    • commonly seen in albino patients
  112. What is dysarthria?
    explosive speech
  113. What is the reticular formation?
    • network of nerve cells that runs vertically from the spinal cord to the thalamus
    • receives sensory input
    • gives off efferent fibers that influence most CNS processes
  114. What are the columns of the reticular formation?
    • one median column
    • two medial columns
    • two lateral columns
  115. With what structure are the reticular formation columns continuous with inferiorly?
    spinal cord gray matter
  116. Where is the reticular formation located inside the midbrain, pons, and medulla oblongata?
    • midbrain: in tegmentum, posterior to substantia nigra, anterior to cerebral aqueduct
    • pons: in tegmentum, posterior to trapezoid body
    • medulla: near the center
  117. Where do afferent projections of the reticular formation come from?
    • spinal cord
    • cranial nerve nuclei
    • cerebellum
    • diencephalon
    • corpus striatum
    • limbic system
    • cerebral cortex
  118. Where do efferent projections of the reticular formation go to?
    • same as afferent
    • autonomic nervous system
    • red nucleus
    • substantia nigra
    • tectum of midbrain
  119. What are the functions of the reticular formation on skeletal muscle?
    • atin-gravity muscle tone
    • reflex activity
    • reciprocal inhibition (flexor vs. extensor)
    • respiratory muscle control
    • emotion-driven control of facial expression muscles
  120. What is wrong if you cannot voluntarily smile, but can if a joke is told?
    • you have a lesion blocking smile nerves in the facial nerve
    • reticular formation is still working
  121. How does the reticular formation affect control of somatic and visceral sensations?
    • facilitation or inhibition of sensations
    • (tones down sensations like pain)
  122. What function does the reticular formation have in the reticular activating system?
    • sensory filter of arousal (decides what is important enough to wake you)
    • differs the states of wakefulness dependant on activity (auto drive vs. bomb squad)
  123. What structures does the spinal cord travel in/through?
    vertebral canal of vertebral column
  124. From what structures does the spinal cord span?
    • foramen magnum
    • L1 vetebrae
  125. Where is the cauda equina located?
    below the spinal cord, starting from L1 and ending in the coccyx
  126. What is the first direction nerves of the cauda travel off of the spinal cord?
    inferiorly in the vertebral canal, towards the vertebrae that the exit from
  127. What structures divide the spinal cord into right and left halves?
    anterior and posterior median fissures
  128. What surrounds the spinal cord?
    • meninges, just like the brain
    • dura
    • arachnoid
    • pia
  129. Where does the dura mater end in the spinal column?
    S2-ish
  130. What are the names of connections in the spinal cord between the pia and arachnoid maters?
    • ligamentum denticulatum
    • thicken between nerve roots gives toothy appearance
  131. What is the name of the collapsed in pia mater that meets with arachnoid and dura mater at S2?
    filium terminale
  132. Where is the filium terminale found in the verterbral column?
    conus medullaris (at L1)
  133. How many spinal nerve pairs emerge from each spinal segment?
    31
  134. What are the structures of the gray matter core in the spinal cord?
    • anterior horn
    • posterior horn
    • commissure
  135. What types of neuron cell bodies does the anterior horn of the gray matter spinal cord have?
    • alpha-efferent
    • gamma-efferent
  136. What are the properties of alpha-efferent neuron cell bodies?
    • large, multipolar cells
    • exit via the anterior spinal root
    • innervate extrafusal skeletal muscle
  137. What are the properties of gamma-efferent neuron cell bodies?
    • small, multipolar cells
    • exit from anterior apinal root
    • innervate the intrafusal muscle fibers of neuromuscular spindle
    • detect stretching info
    • cause stronger stress responses by constricting more
  138. What are the 3 neuron soma bunches of the anterior horn?
    • medial group
    • central group
    • lateral group
  139. Where is the medial group of neuron soma of the anterior horn located?
    througout the spinal cord
  140. What does the medial group of neuron soma in the anterior horn of the spinal cord innervate?
    • neck
    • trunk
    • intercostal
    • abdominal muscles
    • (muscles around axis of body)
  141. Where is central group of neuron soma in of the anterior horn in the spinal cord located?
    • C1-C6
    • L2-S1
  142. What does the central group soma of the anterior horn of the spinal cord innervate?
    • C1-C6: spinal root of accessory nerve (sternocleidomastoid and trapezius)
    • C3-C5: phrenic nerves and diaphragm
    • L2-S1: lumbosacral plexus (innervation unknown)
  143. Where is the lateral group of the neuron soma in the anterior horn of the spinal cord located?
    • cervical area
    • lumbosacral area
  144. What does the latera group soma of the anterior horn of the spinal cord innervate?
    • arm muscles
    • leg muscles
  145. What type of cells go into the posterior (dorsal) horn of the spinal cord?
    mainly afferent axons from the periphery
  146. What are the three sections of the posterior (dorsal) horn of the spinal cord?
    • substantia gelatinosa
    • nucleus proprius
    • nucleus dorsalis
  147. Where is the substantia gelatinosa of the posterior horn of the spinal cord located?
    the apex of the posterior horn
  148. What type of cells interact with each other in the substantia gelatinosa?
    • afferent PNS fibers
    • Golgi type II neurons
    • long descending axons from brain
  149. What does the interaction of so many neurons in the substantia gelatinosa of the posterior horn of the spinal cord allow?
    sensation to be tempered (heightened or dampened) by sensations from other places or the brain
  150. what type of sensation does the nucleus proprius detect/receive?
    • fine sensation
    • proprioception
    • resolution
    • vibration
  151. What does the nucleus proprius receive fibers from?
    posterior white column of the spinal cord
  152. Where in the vertical aspect of the spinal column is the nucleus dorsalis (Clark's column) found?
    from T1 to L3 of spinal cord
  153. What type of soma does the nucleus dorsalis have?
    • large neurons
    • neuromuscular spindles
    • Golgi tendon organs
  154. What type of sensation does the nucleus dorsalis receive?
    • proprioception
    • stretching of muscles
  155. What is the function of the Gray commissure in the spinal cord?
    • connects the right and left halves of the gray matter of the spinal cord
    • decussation of nerve fibers
  156. Through what structure does the central canal of the spinal cord run down?
    the gray commissure of spinal cord
  157. What flows through the central canal of the spinal cord?
    CSF
  158. In what parts of the spinal cord is the lateral horn present?
    • thoracic
    • upper lumbar
  159. What is the lateral horn of the spinal column made of?
    intermediolateral cell group
  160. What is the function of the intermediolateral cell group in the lateral horn of the spinal cord?
    • they are preganglionic sympathetic neurons
    • the preganglionic sympathetic axons come from these soma
    • receives signals directly from the brain
  161. What is the intermediomedial cell group of S2 to S4 of the spinal cord?
    they give rise to the preganglionic parasympathetic fibers of the sacral plexus
  162. What does the amount of gray matter in a section of the spinal cord mean?
    • directly deals with how much information goes in and out of that area of the spinal cord
    • enlargements in areas where info of arms and legs is received
  163. What are interneurons (internuncial neurons) of the spinal cord core?
    • inhibitory (usually) neurons that link two longer neurons together
    • often used in reflex arc to inhibit the action of antagonistic muscle
  164. What are the divisions of the white matter in the spinal cord?
    • anterior
    • posterior
    • lateral columns
    • white commissures
  165. What is the function of the white commissures?
    • there is an anterior and posterior one
    • connect right and left halves of the white matter of the spinal cord
    • they do not cross the gray commissure
  166. What are intersegmental nerve fiber tracts?
    reflexes that require movement in more than one spinal segment
  167. What type of signals do ascending neuronal pathways carry?
    • afferent!
    • exteroception
    • interoception
    • proprioception
  168. What is exteroception?
    • stimulus that comes from outside the body
    • ex: punch in the face, eating something sharp
  169. What is interoception?
    • stimulus that comes from inside the body
    • ex: headache
  170. What makes up the afferent signal pathway three neuron chain?
    • first-order neuron
    • second-order neuron
    • third-order neuron
    • there are some exceptions (more or less neurons)
  171. What are the attributes of the first-order neuron in the afferent signal chain?
    • stretches from sensory receptor in periphery to spinal cord
    • cell body is in posterior root ganglion
    • synapses with second-order neuron
  172. What are the attributes of the second-order neuron in the afferent signal chain?
    • cell body in spinal cord gray matter (sometimes in medulla)
    • usually decussate (with very FEW exceptions)
    • ascends to the brain
    • with third order neuron in the thalamus
  173. What are the attributes of the third-order neurons in the afferent signal chain?
    • cell body in the thalamus
    • sends axons to specific area of cerebral cortex
  174. What are the exceptions of the third-order neurons in the afferent signal pathway?
    • some branch to give info to the reticular formation
    • some participate in a reflex arc
  175. What ascending pathway transmits temperature, pain, light touch, and pressure sensation?
    • the spinothalamic/ spinoreticular tract
    • also called lemniscal system
    • deals mostly with crude sensations, no details or data
  176. What type of nerve do first-order neurons of the spinothalamic tract come from?
    free nerve endings
  177. What side of the spinal cord do first-order neurons of the spinothalamic tract synapse?
    • the ipsilateral posterior gray horn
    • specifically the substantia gelatinosa
  178. How do first-order axons divide when entering the spinal cord?
    • ascending
    • descending branches
    • called postereolateral tract of Lissauer
    • these interact with neighboring spinal segments
    • this spreads sensory info to other dermatomes
  179. What is purpose of pain receptors?
    make person aware of damaging stimuli
  180. What direction do second-order neurons of the spinothalamic tract immediately do?
    • decussate at same level of spinal cord
    • via the anterior gray and anterior white commissures
  181. Which direction do the second-order axons of spinothalamic tract go after decussating?
    ascend in the contralateral anteriolateral white column of spinal cord, medulla, pons, and midbrain
  182. What name is given to second-order fibers of the spinothalamic tract as they ascend collectively up the medulla?
    spinal lemniscus
  183. What do spinal lemniscus always refer to?
    second-order neurons of the spinothalamic tract that are travelling through the brainstem
  184. What does the lateral portion of the anteriolateral white column carry information of?
    • pain
    • temperature
  185. What does the anterior portion of the anteriolateral white column of the spinothalamic tract carry information of?
    • touch
    • pressure
  186. Where do axons of the spinal lemniscus end?
    ventral posterolateral nucleus of the thalamus
  187. Where do third-order neurons of the spinothalamic tract end?
    postcentral gyrus of the cerebrum
  188. What type of fibers carry pain sensation in the spinothalamic tract?
    • fast pain neurons
    • slow pain neurons
  189. What is the function of fast pain fibers in the spinothalamic tract?
    • ascend directly to the thalamus
    • this localizes pain
  190. What is the function of slow pain fibers in the spinothalamic tract?
    • relay in posterior horn of spinal cord before ascending to reticular formation
    • elicits chronic, nauseous, or suffering pain
    • pain you can't pinpoint, but have a general feeling of unwellness
    • also know as the spinoreticular pathway
  191. What is the spinoreticular tract a rare case of how second-order neurons behave?
    • they do not decussate!
    • travel ipsilaterally
    • there are no third order neurons
  192. What are the two theories of managing pain?
    • Gating theory
    • Analgesia system
  193. What is the gating theory of pain management?
    • strong tactile stimuli can inhibit the pain signals through convergence of neurons in the dorsal gray horn of the spinal cord
    • basically: overload the system with all types of receptors will cause pain to be lessoned
  194. What is the anlgesia system theory of pain management?
    • it releases chemical opiods that descend in rebrospinal tract
    • these inhibit spinal neurons that relay pain signals
  195. What is the general rule of pain tolerance between men and women?
    men can tolerate more pain
  196. How do spinovisual reflexes create the correlation of eye reflexes with head movement?
    second-order axons of spinal lemniscus branch off and end in superior colliculi of midbrain tectum (spinotectal tract)
  197. Where do most pain sensations end?
    the somatosensory cortex of the post-central gyrus
  198. What part of the nervous system regulates our emotional responses to pain?
    cingulate gyrus
  199. What part of the nervous system is associated with pain from our internal organs?
    insulate cortex
  200. What type of sensation do posterior white column tracts transmit?
    • fine, discriminitive touch
    • pressure
    • vibration
    • conscious proprioception
  201. Where do first-order neurons of the posterior white column tracts begin?
    • specialized receptors such as:
    • Meissner's corpuscules
    • pacinian corpuscules
    • neuromuscular spindles
    • Golgi tendon organs
  202. Where do first-order neurons of the posterior white column tracts travel to?
    • directly to ipsilateral posterior white column
    • then branch into descending or ascending fibers
  203. What nerves of the posterior white column tracts cause the intersegmental reflexes?
    • descending fibers of first-order axons
    • synapse on spinal cord gray matter neurons
  204. What are the two ascending tracts of the first-order neurons of the posterior white column tract?
    • Fasciculus gracilis
    • Fasciculus cuneatus
  205. What side of the spinal cord do first-order fibers of the posterior white column tracts travel to? (ipsilateral or opposite)
    ipsilateral side
  206. What are the attributes of the fasciculus gracilis?
    • runs along entire length of spinal cord
    • transmits sensory information from lower limbs, abdomen and lower thorax
  207. What are the attributes of the fasciculus cuneatus of the posterior white column tracts?
    • only present in upper thoracic and cervical spinal cord
    • tranmits sensory info from upper limbs, upper thorax, and neck
  208. Where do the axons of the fasciculi gracilis and cueatus end?
    • the nuclei gracilis and cuneatus of the posterior medulla oblongata
    • synapse on second-order neurons here
  209. The soma of the nucleus gracilis and cuneatus are what?
    second-order neurons of the posterior white column tracts
  210. The soma of the nucleus gracilis and cuneatus give off axons called what?
    internal arcuate fibers
  211. What are the attributes of the internal arcuate fibers of the posterior white column tracts?
    • decussate in the medulla bolongata via sensory decussation
    • ascend in the medial lemniscus through medulla, pons, and midbrain
    • end in ventral posterolateral nucleus of thalamus
    • synapse on third-order neurons
  212. What is the spinal lemniscus?
    2nd order neuorns of the spinothalamic tract traveling through brainstem
  213. What is the medial lemniscus?
    2nd order neurons of the fasciculus gracilis and cuneatus tracts traveling through the brainstem
  214. What is the lateral lemniscus?
    2nd order neurons carrying hearing info traveling through the brainstem
  215. What is the Trigeminal lemniscus?
    2nd order neurons from the trigeminal nerve tha have their cell bodies in the trigeminal nucleus
  216. Where do 3rd order axons of the of the posterior white column tract travel?
    • through internal capsule
    • through corona radiata
    • terminate on postcentral gyrus, primary somatosensory cortex
  217. What does the ascending pathway to the cerebellum transmit?
    muscle joint proprioceptive data
  218. How many ascending pathways from the spinal cord to the cerebellum are there?
    4
  219. Where do first-order neurons of the ascending cerebellar pathways synapse?
    the nucleus dorsalis of the posterior gray horn in spinal cord
  220. Where do second order neurons of the ascending cerebellar pathway synapse?
    • mossy fibers travel directly from the nucleus dorsalis to the cerebellar cortex
    • some synapse with neurons in the olivary nuclei
    • from olivary nuclei to cerebellar cortex is third-order fibers, or climbing fibers
  221. What info do descending spinalt tracts carry?
    • efferent signals from the brain to spinal cord
    • allow muscle and glandular activity
  222. What is the general course of descending tracts of the CNS?
    upper motor neurons to lower motor neurons
  223. Where do upper motor neurons start?
    • neuronal soma in cerebral cortex (largest amount)
    • deep cerebral and brainstem nuclei
  224. Where do upper motor neurons synapse in the spinal cord?
    anterior gray horn of the spinal cord
  225. At what structure in the CNS do many descending neurons decussate?
    medulla oblongata
  226. Where do lower motor neurons have their soma?
    anterior gray horn of the spinal cord
  227. Where do lower motor neurons exit from the spinal cord?
    anterior spinal root
  228. What are end destinations of lower motor neurons?
    • muscles
    • glands
  229. What Cranial nerves are considered lower motor neurons?
    3-12
  230. What is the function of interneurons in descending tracts of CNS?
    • don't always exist
    • receive tons of info from different tracts
    • compare info
    • send signal to lower motor neuron
  231. Can lower motor neurons receive info from multiple sources?
    yes; it is called converging input
  232. What are symptoms of an injury to a lower motor neuron?
    • flaccid paralysis
    • atrophy of muscle
    • muscular fasciculation (twitching)
    • loss of reflexes
    • muscular contraction because of atrophy
    • degeneration (invoked stimulus causes nothing
  233. What are the names of the specific descending tracts?
    • corticospinal tract
    • reticulospinal tract
    • tectospinal tract
    • rubrospinal tract
    • vestibulospinal tract
  234. What info does the corticospinal descending tract send?
    efferent info that controls voluntary, skilled movements
  235. What are the upper motor neurons of the corticospinal tract?
    pyramid cells from the cerebra cortex
  236. Where do 2/3 of fibers in the corticospinal descending tract come from?
    precentral gyrus (primary or secondary motor centers)
  237. Where do 1/3 of fibers of the corticospinal descending tract come from?
    postcentral gyrus
  238. What is the function of the descending postcentral gyrus fibers of the coticospinal tract?
    help modulate sensory input
  239. What is the pathway of travel of the pyramid axons of the corticospinal tract?
    • corona radiata
    • porterior limb of internal capsule
    • cerebral peduncle of midbrain
    • anterior pons
    • anterior medulla
  240. What is the function of the branching of descending axons in the medulla oblongata?
    • provides nuclei of other systems with info regarding voluntary movement that is about to take place
    • allows for appropriate signals to occur
  241. The pyramids of the medulla oblongata are formed from?
    axons of pyramid cells
  242. Where do 80% of descending pyramid axons decussate?
    inferior border of the medulla, conveniently named decussation of the pyramids...
  243. Is the coticospinal tract decussation inferior or superior to the fascuculus gracilis and fasciculus cuneatus decussation?
    inferior
  244. What structure do contralateral corticospinal tracts travel through after decussating?
    • lateral white column of spinal cord
    • terminate in the anterior gray horn of spinal cord
  245. What would an injury to the corticospinal tract above the decussation cause?
    muscular paralysis on the contralateral side
  246. Where do 20% of non-decussating fibers travel in the corticospinal tract?
    • the ipsilateral anterior corticospinal tract in the anterior white column of the spinal cord
    • these then decussate at the spinal level
    • terminate on the anterior gray horn
  247. What would an injury to the anterior corticospinal tract cause?
    contralateral motor defect
  248. What is the Babinski reflex?
    • injury or incomplete upper motor neuron myelination
    • tickling foot reaction should be clinching toes and pulling foot away
    • when damaged, toes just spread
  249. What is the superficial abdominal reflex?
    • normal - scratch skin over abs, abs muscles will contract
    • if uppermotor neuron is damaged there is no contraction
  250. What is the cremaster reflex?
    • normal - stroking medial side of male thigh will make scrotum ascend
    • upper motor neuron injury will cause no movement in cremaster muscle
    • only works on males...
  251. What is the function of the reticulospinal tract?
    • encourage (excitatory) or inhibit voluntary movement and reflex activity
    • not a prime-mover
    • purely supportative
  252. whatis the pathway of the reticulospinal tract?
    axons from reticular formation that descend in spinal cord to lower motor neurons
  253. What other tracts are included in the reticulospinal tracts?
    descending autonomic tracts
  254. What does the descending autonomic tract influence?
    sympathetic and parasympathetic neurons of hte intermediolateral and intermediomedial nuclei of spinal cord
  255. What is origin and pathway of the testocpinal tract?
    • superior colliculus
    • medial longitudinal fasciculus
    • entire length of spinal cord in anterior white column
    • most fibers decussate before leaving midbrain
  256. The medial longitudinal fasciculus connects nuclei of what cranial nerves?
    • 3
    • 4
    • 6
    • 8
  257. What is the function of the tectospinal tract?
    • connect head with vision
    • moves the head with eyes
    • postural reflexes as a respones to visual stimuli
  258. Why are the spinotectal sensory pathway and the tectospinal pathway connected?
    so the spinotectal tract can turn on the tectospinal tract
  259. Where do the axons of the rebrospinal tract come from?
    soma of red nucleus in the midbrain tegmentum
  260. When do rebrospinat tract axons decussate?
    immediately in the midbrain
  261. What is the pathway of the rubrospinal tract?
    • mibrain
    • pons
    • medulla
    • lateral white column of spinal cord
    • anterior gray horn interneurons
  262. What is function of rebrospinal tract?
    • allows cerebrum and cerebellum to indirectly affect muscles
    • flexors facilitated
    • extensors (antigravity muscles) inhibited
  263. Where does vestibulospinal tract get info from?
    • vestibular portion o fhte inner ear
    • cerebellum
  264. What is the pathway of the vestibulospinal tract?
    • descends in anterior white column of spinal cord
    • synapse on anterior gray horn interneurons
  265. What is the function of the vestibulospinal tract?
    • maintain balance by facilitating extensors and inhibiting flexors
    • opposite of rebrospinal tract
  266. What is spinal shock syndrome?
    injury to spinal cord causes functions below injury to be depressed for a time
  267. What are symptoms of spinal shock syndrome?
    • flaccid paralysis
    • sensory impairment
    • reflex depression
  268. What symptoms occur in recovery of spinal shock syndrome?
    • spastic paralysis
    • exaggerated reflexes (loss of descending tract influence)

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