25. Swallowing

Question 1

What CNs are active sensory and/or motor in swallowing?

What other parts of the brain/nervous system are active in swallowing? What are their roles?

What are the afferent and efferent pathways of swallowing?

Answer 1

motor and sensory: CN 5, 7, 9, 10
only motor: CN 12

Medulla Oblongata = swallowing center, triggers swallow
Central Pattern Generator = control patterned swallow response

Afferent Pathway = to Nucleus Tractus Solitarius (NTS) via CN IX, X (VII)

Efferent Pathway = to Nucleus Ambiguus (NA) via CN IX, X, XII

Question 2

What are the 3 main phases of swallowing?

Describe the steps of the 1st phase

Answer 2

Oral, Pharyngeal, Esophageal

1. bolus enters oral cavity, mastication
2. tongue contracts hard palate to prevent bolus loss
3. soft palate contracts post. tongue to prevent bolus loss
4. Bolus transport begins
   a. Velum (soft palate) elevates
   b. buccal/lip muscles contract (prevent bolus falling out)
   c. post. tongue depresses, and tongue tip elevates
   d. midline of tongue “strips” bolus posteriorly

Question 3

Describe the steps of the 2nd and 3rd phases of swallowing.

Answer 3

Pharyngeal - initiation of REFLEXIVE swallow response

1. soft palate elevates and contracts post. pharyngeal wall
2. hyolarynx complex moves ant and sup
3. epiglottis inverts
4. tongue base retracts to post pharyngeal wall
5. pharyngeal wall “strips” to move bolus down
6. pharynx shortens
7. true/false vocal cords contract/close
8. upper esophageal sphincter opens

Esophageal - peristalsis (involuntary, progressive, wave-like muscular contractions transport food from bolus to stomach)

Question 4

What are 5 ways the airway is protected during swallowing?

Answer 4

1. hyolaryngeal complex moves ant and sup
2. Epiglottis inverts
3. bolus moves around vestibule, along ary-epiglottic folds (NOT over)
4. tongue base retraction to post. pharyngeal wall
5. vocal folds close (false and true)

Question 5

Dysphagia:
what it is
who it affects
signs
impact

Answer 5

Trouble swallowing (Sx not a disease)
More common in older adults
Signs: coughing during eating/drinking, wet/gargly voice after eating/drinking, throat clearing during/after eating drinking, unintentional weight loss, change in eating habits
Impact: aspiration (food falls BELOW vocal folds; silent aspiration - pt does not notice - no cough)
aspiration pneumonia (does not always occur with every aspiration episode)
penetration (food falls into ventricle, ABOVE vocal folds)
Malnutrition - insufficient nutrients into body
Dehydration - insufficient water in body
Weight Loss

Question 6

What is cricopharyngeal bar?

Answer 6

Thickening of cricopharyngeal muscle - outpouches into esophageal space
Due to aging/inflammation

Question 7

What are two tests for dysphagia?

How is dysphagia managed?

Answer 7

1. Modified barium swallow study - radiographic eval by speech path or radiology
2. Fiberoptic endoscopic evaluation of swallowing - endoscope through nasopharynx, superior view of swallowing by speech path or ENT

Mgmt: targeted exercises, postural/positioning changes, strategies to maximize safety/efficiency, diet modifications (thick liquids, altered solids)