anatomy of swallowing

Question 1

what are the three phases of swallowing

Answer 1

• oral phase
• pharyngeal phase
• oesophageal phase

Question 2

what is involved in the oral phase

Answer 2

Masticatory muscles (CN V3) breakdown food and allow it to mix with saliva.

Facial muscles (CN VII) creates
Labial seal (orbicularis oris) 
Tightens cheek (buccinator)

Intrinsic and extrinsic tongue muscles (CN XII) manipulate bolus and align it between dentition and push it against hard palate.

Soft palate (CN X) depresses to create a oropharyngeal seal and tongue ‘ripples’ bolus posteriorly

Question 3

what is involved in the pharyngeal phase

Answer 3

• hyolaryngeal elevation

- sequential constrictor contraction

Question 4

what is involved in the oesophageal phase

Answer 4

relaxation of upper oesophageal sphincter

Question 5

what is the course of CN XII

Answer 5

• extends from the medulla
• passes through the hypoglossal canal
• descends close to the carotid sheath
• courses lateral to hypoglossus into floor of mouth

Question 6

what is the pharyngeal phase facilitated by

Answer 6

Elevation of soft palate
-Seals off nasopharynx from oropharynx
Posterior pressure from tongue
-Seals off laryngeal aditus with help from epiglottis 
Hyolaryngeal elevation
-Protects airway
-Opens upper oesophageal sphincter
Pharyngeal constrictor contraction

Question 7

explain the process of hyolaryngeal elevation

Answer 7

Hyoid bone is dragged superiorly and anteriorly by

• Suprahyoid
• Longitudinal pharyngeal muscles

Coupled with posterior tongue pressure from
-Stylohyoid and hyoglossus

Forces the epiglottis inferior to the tongue and covers the laryngeal aditus

Question 8

what aids the movement of food from the laryngopharynx to the oesophagus

Answer 8

• tongue
• sequential contraction of pharyngeal constrictors superior
• relaxation of upper oesophageal sphincter

Question 9

what is the function of the pharyngeal plexus

Answer 9

• innervates the muscles soft palate and pharynx
• except tensor veli palatini
• sensory component of the mucosa
• formed by CN IX and CN X

Question 10

where is the stimuli presented for gag reflex

Answer 10

posterior 1/3 of tongue, palatine tonsils or wall of oropharynx

Question 11

what are the muscles involved in gag reflex

Answer 11

• constrictors of pharynx
• longitudinal muscles of pharynx
• tongue and oft palate