Ch. 15: Brain Stem Region Flashcards Preview

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Flashcards in Ch. 15: Brain Stem Region Deck (24):

What are the 3 divisions of the brainstem?

  1. Medulla
  2. Pons
  3. Midbrain


What are the 3 divisions on the brainstem?

  • Base (basilar) - primarily motor tracts & function
  • Tegmentum - primarily sensory tracts and function
  • Tectum - reflexive control of eye movements and movements of the hard

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What are the important structures on the ventral and dorsal Medulla?

  • Ventral
    • Pyramids
    • Cranial nerve roots (9,10,11,12)
  • Dorsal
    • Sensory tracts - touch and proprioception


What are the important internal structures of Medulla?

  • Basilar
    • Corticospinal tracts: voluntary control of body - passess through
    • Medial Lemniscus: conscious touch and proprioception - passes through
  • Tegmentum
    • Spinothalamic tracts: pain & temp from body
    • Trigeminothalamic tracts: pain & temp from face
    • Reticular Formation (5 broad categories)
    • Autonomic "control" nuclei.


What are the important ventral and dorsal parts of the Pons?

  • Ventral
    • "Bulge" of pontine nuclei and pontocerebellar fibers
    • Cranial nerve roots
      • 5 (body of pons)
      • 6,7,8 (border or pons and medulla)
  • Dorsal
    • Cerebellar peduncles - fiber bundles that connects to movement system (3 of them - 2 in, 1 out)


What are the important internal anatomy parts of the Pons?

  • Basilar.
    • Corticospinal tract.
    • Pontine nuclei (origin of pontocerebellar fibers)
    • Corticobrainstem tract.
  • Tegmentum
    • Medial lemniscus. (touch and proprioception)
    • Spinothalamic tracts.
    • Trigeminothalamic tracts.
    • Reticular formation.
    • Autonomic "control" nuclei.


What are the important ventral and dorsal external anatomy of the Midbrain?

  • Ventral.
    • Cerebral peduncles.
    • Cranial nerve root (3)
  • Dorsal.
    • Superior colliculi.
    • Inferior colliculi.
    • Cranial nerve root (4)


What are the important internal anatomy of the Midbrain?

  • Basilar.
    • Cerebral peduncles.
    • Substantia nigra.
  • Tegmentum.
    • Red nucleus.
    • Pedunculopontine nucleus.
    • Oculomotor complex (CN 3, 4).
    • Periaqueductal gray.
  • Tectum.
    • Superior colliculi.
    • Inferior colliculi.


What are the 5 function of the Reticular Formation?

  1. Projections can raise/lower arousal
  2. Provide autonomic control (Homeostasis)
    1. Vital centers of brain stem (ex: Jean's class)
  3. Broadly control consciousness and sleep/wake
  4. Descending pain control system
  5. Nonspecific activating tracts - inc excitability to LMN in response to fight/flight stimulus


What can cause disorders of the brainstem region?

  • Ischemia (stroke)
  • Compression (growing tumor or inc CSF volume)


What are the differences between damage of a Vertical Tract vs Segmental

Ex: Damage to UMN or LMN contorlling muscles of fascial expression 

  • Vertical tract ("above" brainstem) opposite {B}
    • Damage to cerebral cortex or corticobrainstem tract (vertical tract of facial function) rostral to the brainstem
      • Corticobrainstem tract - UMN
    • Presentation: Paresis or paralysis in "lower" 1/4 of contralateral side of face - can still close eyes and smile on one side, no smile on CONTRALATERAL side from injury
  • Segmental (exiting brainstem) - Same side {A}
    • Damage to CN VII (Facial) on one side of brainstem (either LMN cell body or LMN axon or both)
      • CN VII - LMN of Facial function
    • Presentation: Paresis or paralysis in entire ipsilateral 1/2 of face

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What are the differences between damage of a Vertical Tract vs Segmental

Ex: Stroke in Anteromedial Medulla (vertebral artery) 

  • Vertical tract (passing through brainstem)
    • Corticspinal tract: Paralysis of arm/trunk/leg - Contralateral to damage
    • Medial lemniscus: loss of touch from body - contralateral to damage
  • Segmental (exiting brainstem)
    • Hypoglossal (CN 12 nucleus or nerve): Paralysis of tongue (ipsilateral to damage) → tongue points to same side of damage
    • UMN comes from opposite side - brought down through corticobrainstem tract


What is the guiding principle for brainstem damage?

  • Signs and sx to ipsilateral face and contralateral body


What is the result of unilateral brainstem damamge?

  • Vertical tracts (body)
    • Contralateral signs/sx
      • (DC/ML, spinothalamic, corticospinal)
  • Cranial nerve nuclei
    • Ipsilateral signs/sx
  • Cerebelluum
    • Ipsilateral signs/sx
  • Autonomic
    • Ipsilateral signs/sx


Damage to what structures could cause disorders of vital function?

Damage to cardio and respiratory control centers in the medulla


What are the 4 D's of brainstem region Dysfunction?

  • Dysphagia: trouble swallowing
    • 9 (detects food and shovels back), 10 (closes windpipe)

    • Potential side effect: aspiration, undernourished

  • Dysarthria: difficulty with speech
    • 5 (move jaw),  7 (especially lips), 10 (control windpipe and vocal cords), 12 (t's and d's)

  • Diplopia: double vision
    • 3,4,6 - extraoccular controllers
  • Dysmetria: difficulty reaching for target
    • any cerebellar peduncles


What is the order of disorders of consciousness?

  1. Syncope
  2. Delerium
  3. Otunded
  4. Stupor
  5. Minimally conscious state
  6. Vegatative State
  7. Coma


What is a Coma?

Asleep and unresponsive

(Brainstem squeezed pretty bad)


What is a Vegetative State?

Unresponsive, normal wake/sleep cycle, eyes open/close

(next level up from coma)


What is a Minimially Conscious State

Responsive but in very small, very select way


What is a Stupor?

Depressed or labored level of conscious

(respond only to a very strong stimulus)


What is Obtunded?

Sleepy, drowsy


What is Delerium?

Decreased interaction

(more cognition than conscious)


What is Syncope?

Fainting/brief loss of consciousness

(ex: orthostatic hypotension)