MSD: Cranial Nerves and functional divisions

  1. The final common Pathway (FCP)
    a LMN system. The last link in the events that leads to movements.  It stimulates muscle contraction and movement.
  2. Indirect activation pathway (IAP)
    • meditates subconscious, automatic muscle activities including posture, muscle tone and movement that support and accompany voluntary movement.
    • -corticobulbar and corticoreticular tracts
    • -relay messages to UMN, indirect motor system and extrapyrimidal system
  3. Direct Activation Pathway (DAP)
    • influences consciously controlled, skilled voluntary movements. Sends messages through the corticobulbar and the corticospinal tract.
    • -relays messages to UMN, direct motor system and pyramidal tract
  4. CN V: Sensory
    Face forehead nose mouth
  5. CN V Motor
    Muscles of mastication, mylohyoid, anterior belly digastric, tensor tympani, tensor veli palatini
  6. CN V damage
    • LMN lesions lead to paresis, paralysis and atrophy of muscles of mastication
    • -unilateral damage do not have major effects
    • -bilateral lesions cause jaw to hang open, difficulty moving it, difficulty articulating
  7. Facial cranial nerve VII: Motor
    Facial expressions and the stapedius muscle
  8. Facial cranial nerve VII:sensory
    innervate glands, taste receptors on the anterior 2/3 of tongue, and nasopharynx
  9. Facial cranial nerve VII:LMN lesions
    Paralyze muscles on the ipsilateral side of face, atrophy occurs resulting in facial asymmetry, they affect all voluntary, emotional and reflex movements of face
  10. Glossopharyngeal nerve (IX)
    • Motor: stylopharyngeous and upper constrictor muscles of the pharynx
    • Sensory: pharynx tongue Eustachian tube
  11. Glossopharyngeal nerve (IX) Lesions
    reduced pharyngeal sensation, a decrease in gag reflex, and reduced pharyngeal elevation during swallowing.
  12. Vagus X
    • Motor: soft palate, pharynx and larynx
    • Sensory: transmits info from the above structures
  13. Vagus X lesions
    • cause weakness to soft palate, pharynx, larynx, and palatoglossus
    • -unilateral damage can affect resonance, voice quality and swallowing but usually affect phonation more prominently.
    • -bilateral LMN lesions: all the same plus articulation precision
  14. Accessory nerve XI
    • Motor: Uvula, levator veli palatini, and intrinsic laryngeal muscles. Sternocleidomastoid and trapezius
    • lesions: hard to move neck or shoulders
  15. Hypoglossal nerve XII
    • Motor: all tongue muscle but one
    • sensory: sends taste and tactile info important for chewing and swallowing
  16. nerve XII lesions
    atrophy, weakness and fasciculations of the tongue on the side of lesion
  17. Spinal nerves
    contribute to respiration
  18. Basal Ganglia control circuit Function:(5)
    • 1. Posture and tone regulation
    • 2. Start intended movements and inhibit unwanted movements
    • 3. set switching
    • 4. Movement selection and learning
    • 5.Cognitive, affective and motor control functions
  19. Basal ganglia control circuit: lesions
    • reduced mobility (hypokinesia)
    • involuntary movements (hyperkinesia)
    • produce more porfound MSDs
  20. Basal ganglia control circuit: Speech sensation
    • sensory knowledge of where the articulators are positioned and where they need to go
    • incorporate thalamus and sensory info with movement control
    • -these help to make reliable acoustic signals
  21. Basal ganglia control circuit: reflexes, learning and automaticity of movements for speech
    big effect on planning and programming, IAP interruption
  22. Cerebral control circuit influences:
    basal ganglia plus cerebellum involved in speech control. they provide input to cortical areas involved in planning and programming
  23. limbic system
    regulating memory and learning, drive and motivation, emotion for speech-programs part of the content
  24. reticular formation and thalamic influences on speech
    activates the FCP, and the IAP and DAP
Card Set
MSD: Cranial Nerves and functional divisions
Cranial Nerves and functional divisions