week 2 Flashcards
(25 cards)
Name 4 MOTOR CN
- trigeminal (CN V) third branch
- Facial (CN VII)
- Vagus (CN X)
- Hypoglossal (CN XII)
Describe simplified motor pathway
signal passes through motor cortex into the brainstem –> signals cross paths and travel brain stem nucleus –> into motor nucleus –> lower motor neurons –> project through cranial nerve
Name 4 SENSORY CN
- trigeminal CN V (2nd and 3rd branches)
- facial (CN VII)
- Vagus (CN X)*
- Glossopharyngeal (CN IX)*
Describe simplified sensory pathway
being at sensory receptors –> project to the sensory nuclei in brainstem –> and up to sensory to cortex
reversed pathway
Name the 2 major branches of Vagus nerve CN X
- Superior Laryngeal Nerve (SLN)
- Recurrent Laryngeal Nerve (RLN)
What is SLN
Superior Laryngeal Nerve
sensory branch of CN X
internal branch - sensory above VF (think penetration)
External branch - motor to cricothyroid muscle (lengthen VFs)
What is RLN
Recurrent Laryngeal Nerve
motor branch of CN X
sensory below VF (think aspiration)
motor to all intrinsic laryngeal muscles EXCEPT cricothyroid
T/F
Hypoglossal is a motor only CN involved in swallowing
true
of branches
CN V Trigeminal:
function
clinical importance including swallowing phase
sensory and motor nerve
sensory: oral prep phase - bolus sensation and pocketing in sulci (V2 & V3)
motor: muscles of mastication (Masseter, soft palate); involved in all 3 swallow phases
oral prep - swallowing
oral phase - prevents nasal regurgitation
pharyngeal - stabilizes jaw for hyoid movement
How to test CN V trigeminal
sensory: touch areas of face
V1 - ventral, forehead, nose
V2* - upper lip, cheek, temple
V3* - lower lip, chin, above ear
motor:
clench teeth, open close against resistance
*important branches for swallowing
CN VII Facial
function
clinical importance including swallowing phase
Sensory and motor
sensory: taste; important taste is motivator; sour boluses have increased pharyngeal swallow
Motor: muscles of facial expression; salivary glands; create oral seal, saliva production and bolus containment in oral prep stage and UES opening via hyolaryngeal traction during pharyngeal phase
How to test CN VII Facial
Sensory and motor
sensory - do not test taste sensation typically
motor - smile and pucker
What is the pharyngeal plexus
Glossopharyngeal (CN IX) & Vagus (CN X) travel together in pharyngeal complex
difficult to tease apart in CN exam
sensory info that travel along pharyngeal plexus are very important
CN IX Glossopharyngeal
CN X Vagus
function
clinical importance including swallowing phase
travel together in pharyngeal plexus
Sensory and motor
sensory:
CN IX - taste and touch sensation of mucosa (soft palate) and facial pillars
CN X - tactile sensation of pharynx, larynx, esophagus and external ear
important because initiation of pharyngeal swallow (sensation of bolus in pharynx) and airway protection (sensation of post swallow residue)
Motor:
CN IX: stylopharyngeus (shorten pharynx) and salivary gland
CN X: vellum and palatoglossus, larnygeal muscles, cricothyroid, pharngyeal and upper esophagus
difficult to test in CN exam
important in all swallow stages mostly Pharyngeal including bolus propulsion, laryngeal elevation, and UES opening
CN XII Hypoglossal
function
clinical importance including swallowing phase
Hypo - below
Glossal - tongue
motor only CN - both intrinsic (insert one example) and extrinsic (insert one example) tongue muscles except palatoglossus (which is CN X)
important for bolus manipulation and containment and transfer (oral prep phase)
Pharyngeal swallowing is controlled and triggered by a complex system of neurons in the reticular formation of the brain steam called the _____
central pattern generator (CPG): a biological neural network that produces rhythmic patterned outputs without sensory feedback (can’t stop swallow once it begins)
the swallowing CPG is organized into 2 main groups of interneurons:
Dorsal swallowing group (DSG)
- sensory
- received sensory input to shape and time the sequential swallow pattern
Ventral swallowing group (VSG)
- motor
- distributes the motor drive to other motor neurons into the brainstem to execute swallow
These are swallowing reflexive movement modulated by brainstem
where does central pattern generator (CPG) occur
pharyngeal plexus
The pharyngeal plexus lies on the posterolateral wall of the pharynx, mainly over the middle pharyngeal constrictor and is the main motor and sensory nerve supply to the muscles of the pharynx and soft palate and acts to coordinate swallowing and speech
Location of DSG
dorsal swallowing group is located in the nucleus tractus solitarus (NTS) of the medulla
Location of VSG
ventrolateral medulla
T/F
In the CPG, sensory drives motor response
true
sensory input comes before motor
V: Trigeminal Tongue (anterior 2/3)
Area of Innervation
Effect on Swallowing
Mandible
- Loss of sensation
- Inability to mobilize the mandible for chewing
VII: Facial
structures
Area of Innervation
Effect on Swallowing
Lips, cheeks
- Difficulty closing lips firmly: Drooling, problems controlling food position in the mouth
- Loss of taste
IX: Glossopharyngeal
Area of Innervation
Effect on Swallowing
Posterior part of the tongue
and oropharynx
- Loss of taste, loss of sensation from posterior 1/3 tongue, palate, pharynx
- Absent gag
- Delay in swallow triggering
