Oral phase

Question 1

What happens in the oral phase?

Answer 1

• mouth closes
• bolus is propelled backwards from oral cavity into the oropharynx
• laryngeal inlet is pulled up beneath posterior part of tongue, and oropharynx widens ready to receive bolus
• this phase is under voluntary control but can be performed automatically

Question 2

Tongue movements in the oral phase

Answer 2

1) the tip of the tongue is elevated against the anterior part of the hard palate
2) the remainder of the tongue elevates in a progressively posterior movement, gradually obliterating oral cavity and forcing bolus backwards
3) the posterior end of the tongue is depressed
4) as the bolus moves backwards, the posterior tongue changes shape - lateral tongue margins are elevated by the styloglossus to form a U-shaped chute directing food into the oropharynx
5) As the anterior tongue moves upwards, there is simultaneous movement of the hyoid bone upwards and forwards

Question 3

The hyoid bone acts as a stabilising point between the ___ and the ____

Answer 3

The hyoid bone acts as a stabilising point between the TONGUE and the LARYNX

Question 4

Which muscles move the hyoid bone?

Answer 4

The extrinsic muscles of the larynx
(suprahyoid muscles run from hyoid bone to base of skull and mandible, infrahyoid muscles run from hyoid bone to sternum and clavicle)

Question 5

What happens when the suprahyoid muscles shorten?

Answer 5

hyoid bone elvates -> elevates larynx position

Question 6

What happens when the muscle tension increases in the surpahyoid muscles?

Answer 6

hyoid position is fixed relative to tongue and jaw

Question 7

What happens when the infrahyoid muscles shorten?

Answer 7

hyoid bone lowers -> lowers larynx position

Question 8

What happens when the muscle tension increases in the infrahyoid muscles?

Answer 8

fixes hyoid position relative to the larynx

Question 9

What does upward and forward movement of the hyoid bone do?

Answer 9

• increases the dimensions of oropharynx
• provides a stable base for tongue actions
• pulls the laryngeal inlet up beneath the posterior part of the tonge - moves airway out of the path of the bolus

Question 10

Suprahyoid muscle nerve innervation

Answer 10

trigeminal and facial nerves, hypoglossal nerve

Question 11

infrahyoid muscle nerve innervation

Answer 11

C1-C3 nerve roots