Ch. 15: Brain Stem Region Flashcards Preview

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Flashcards in Ch. 15: Brain Stem Region Deck (24):
1

What are the 3 divisions of the brainstem?

  1. Medulla
  2. Pons
  3. Midbrain

2

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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3

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

4

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.

5

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)

6

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.

7

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)

8

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.

9

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

10

What can cause disorders of the brainstem region?

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

11

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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12

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

13

What is the guiding principle for brainstem damage?

  • Signs and sx to ipsilateral face and contralateral body

14

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

15

Damage to what structures could cause disorders of vital function?

Damage to cardio and respiratory control centers in the medulla

16

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

17

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

18

What is a Coma?

Asleep and unresponsive

(Brainstem squeezed pretty bad)

19

What is a Vegetative State?

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

(next level up from coma)

20

What is a Minimially Conscious State

Responsive but in very small, very select way

21

What is a Stupor?

Depressed or labored level of conscious

(respond only to a very strong stimulus)

22

What is Obtunded?

Sleepy, drowsy

23

What is Delerium?

Decreased interaction

(more cognition than conscious)

24

What is Syncope?

Fainting/brief loss of consciousness

(ex: orthostatic hypotension)