Swallowing

Question 1

Oral phase

Answer 1

Close mouth to prevent drooling
Tip of tongue moves to hard palate
Tongue pushes bolus to oropharynx
this is the only voluntary part
Swallowing reflex is initiated and now it is an all or nothing reflex
Afferent impulses travel to the swallowing centre (pons&medulla)
Efferent impulses travel to skeletal muscles of pharynx and larynx

Question 2

Pharyngeal phase

Answer 2

Soft palate moves upwards
Inhibition of ventilation - prevent bolus going to airways
Laryngeal muscles close glottis and raise larynx
Bolus enters oesophagus through open UOS
Glottis re-opens
Breathing resumes

Question 3

Oesophageal phase

Answer 3

Swallowing centre (pons&medulla) triggers closure of UOS and primary peristaltic wave (via CNX)
Peristalsis continues (by ENS)
Opening of LOS allows food to pass to stomach