MUHAMMAD ARIFF B. MAHDZUB (MBBS)

1. Mechanism of swallowing
(deglutition)
PREPARED BY: MUHAMMAD ARIFF B. MAHDZUB
BACHELOR MEDICINE AND SURGERY (MBBS)
UNIVERSITY COLLEGE SHAHPUTRA, KUANTAN

2. Mechanism of swallowing
(deglutition)
The sequence events:
a. Buccal stage (voluntary)
b. Pharyngeal stage (involuntary)
c. Oesophageal stage (peristalsis)

3. Buccal stage (voluntary)
• The tongue retracts to force the bolus into the
oropharynx by the contraction of mylohyoid
muscle

4. a) protective phase
• They soft palate rises to close
off nasopharynx and prevent
bolus from rising into the
nasal cavity
• The larynx elevate and the
glottis closes(by epiglottis)
Pharyngeal Stage (involuntary)

5. • Oropharyngeal isthmus closed
(Base of tongue touching the soft
palate)
• Pharyngeal constrictor contract

6. b) pharyngeal peristalsis
• as pharyngeal constrictor contract, the UES
relaxes to allow the bolus to move from the
oropharynx into the upper oesophagus

7. Oesophageal Stage (8-20 seconds)
• Primary peristalsis begins and both the LES
and stomach relax
• The bolus moves into stomach and LES closes.
• water bolus moves by gravity while semisolid
by peristalsis
• Peristalsis rapid in upper third while slow in
lower third, it starts as primary ( continuation
of pharyngeal) or secondary by oesophagus if
primary failed

8. PBL cases
• Ms Senna, got bulging at her neck

9. Patient information sheet 2

11. • Bulging move up as its
follow the larynx
elevation (Pharyngeal
Stage)
• Enlrg. thyroid wraps
around esophagus
• Compressed the
pharynx and
oesophagus lead to
Dysphagia
-Swelling moves up during swallowing-

12. -There s bruit heard over neck swallowing-
• Bruit : vascular murmur
• Causes: compression of enlarge thyroid gland
to blood supply