Swallowing

Question 1

Oral phase

Answer 1

TIME: After Mastication
NOTE: Breathing stops for the entire process
1). Tongue presses bolus on the hard palate starting with the front of mouth to the back of mouth

2). Activates the mechanoreceptors in the region

3). Info is sent to the brainstem(swallowing center)

4). Soft palate musculature contracts(brings up the flap that separates the nasopharynx and the oropharynx)

5). The 1.Superior 2.Middle 3.Inferior pharyngeal constrictors contract moving the bolus downward

Question 2

Pharyngeal phase

Answer 2

TIME: After ORAL PHASE
1). Muscles pf the base of the tongue and the trachea will contract which moves the trachea up and forward—>opens up upper esophageal sphincter(UES)

2). Then Vocal chords at the top of the trachea closes(V shape to a I shape)

3). Food bolus pushes down on the epiglottis and rolls downward towards esophagus

Question 3

Esophageal phase

Answer 3

TIME: Bolus enters esophagus
NOTE:
-Esophagus exhibits background contraction(throat is closed)
-Swallowing center activates PNS OUTput
-Tone in esophagus mediated by PNS

1).
-Soft palate RELAXES
-Vocal chords open
-Epiglottis springs back up
-Breathing resumes
-UES closes(LES opens ~1sec later which stops acid reflux)

2). Deglutative relaxation
3).

Liquids: flow down to stomach
Viscous liquids/food: PRIMARY contraction(usually gets down to the stomach) and SOMETIMES SECONDARY contractions
Guzzling: quick successive swallows that load up the hypopharyngeal region and then after the last swallow calls for PRIMARY contraction

Question 4

Lower esophageal sphincter

Answer 4

Inspiration: INCREASES tone of LES
After food enters stomach: INCREASES tone of LES

Question 5

Transient LES Relaxation(TLESR):

Answer 5

Burping

Question 6

Systemic Scleraderma

Answer 6

Swallowing Disorder: Autoimmune disease which attacks smooth muscle in the entire GI tract

-Lack peristalsis in the later 2/3 of the esophagus
-LES loses its tone–>Acid Reflux

Question 7

Chagas Disease

Answer 7

Achalasia: Can’t control swallowing
-No peristalsis in the esophagus
- The entire esophagus is relaxed and diluted
-LES tightly closed(stuck there and builds up in the esophagus)

Vector: the assassin bug/kissing bug feces entering orifices
Mechanism: toxin is produced affecting the heart, enteric NS, and other neurons
Treatment: Nitrates and Botox(relaxes LES)

Question 8

Neuronal muscular diseases

Answer 8

Stroke, parkinsons, polio: uncoordinated contractions
Treatment: aspirated into the nasal passage to trachea