Transcript Anatomy and Mechanism of swallowing

Anatomy and Physiology of
swallowing
Kwong Lee, Lee Fan, Felicity,
Camilla, Sai Yan
Anatomy and Physiology of
swallowing
• 3 stages:-
Oral phase ( oral preparatory + oral
transit )
Pharyngeal phase
Oesophageal phase
Oral phase (1): oral
preparatory phase
• Movement of the
mandible (masseter,
temporalis, lateral and
medial pterygoid
muscles)
• Formation of food into
bolus
• Food held
anterolaterally against
the hard palate
• Process requires taste,
temperature, touch
and proprioreception
senses
Oral phase (2): oral transit
phase
• Manipulation of food
bolus in central portion
of tongue
• Sequential anterior to
posterior tongue
elevation
• Triggering pharyngeal
reflex as bolus enters
pharyngeal phase
• Voluntary phase
controlled by the
cerebral cortex
(corticobulbar tract)
Pharyngeal phase
• Reflex < 1s
• Stimulation of
swallowing receptor
areas –tonsillar pillars
 brain stem
• Closure of the nasal
part of the pharynx
 Soft palate elevation –
levator veli palatini
 Pulling forward of the
posterior pharyngeal
wall – superior
constrictor muscle
 Contraction of the
palatopharyngeal
muscle
Pharyngeal phase (cont’d)
• Larynx pulled upward
by contraction of
stylopharyngeus,
salpingopharyngeus,
tyrohyoid and
palatopharyngeus
muscles
• Elevation of the larynx
beneath the
posteriorly bulging
tongue displaces the
epiglottis backwards –
closure of the larynx
Pharyngeal phase (cont’d)
• Bolus moves downward
over the epiglottis and
reach lower part of
the pharynx –
contraction of
superior, middle and
inferior constrictor
muscles
• Upward movement of
larynx pulls up and
enlarges the opening
of the oesophagus
• Relaxation of UOS
Oesophageal phase
• Final phase
• Involuntary
• Peristaltic wave from
UOS to LOS to
stomach - 1° and 2°
• 1° - continuation of
waves from pharynx,
controlled by skeletal
nerve impulses from
IX and X nerve
Oesophageal phase (cont’d)
• 2° - inititated by
myenteric nervous
system and vagal
afferent fibres 
medulla vagal
efferent
• Relaxation of LOS
In Summary