phases of deglutition

1. presented by
Dr Ravi Kumar Seth

2.  It is the process by which food is passed from
oral cavity to stomach.
 It is a reflex activity by which bolus pass into
the stomach.
 The act of swallowing initiated in the region
of the brain stem known as Swallowing
centre

3.  Swallowing rate-600 times per day.
 Volume of swallow in children- 5 ml
 In adult women – 10-15 ml.
 In men – 15-20 ml.
 It has protective function also.

5.  Formation of food bolus.
Oral phase(buccal phase)
 After formation of bolus.
 Lips are closed and maxillary and mandibular teeth
comes together.
 The tongue moves upward towards the anterior
hard palate and passed the bolus into the pharynx.

6.  The nasopharynx is
blocked by the
upward movement
of the soft palate
and forward
movement of the
posterior
pharyngeal wall.
 Respiration is
stopped during this
phase.

7.  Posterior part of the tongue
moves like a piston at the
beginning of this phase.
 That move the bolus into
the hypo pharynx from the
oropharynx.
 Pharynx moves upward and
forward – to pass the bolus.
 The upper oesophageal
sphincter opens and the
bolus enters into the
oesophagus.

8.  The laryngeal vestibule closes at this time by
epiglottis.
 The movement of epiglottis is upward to
horizontal by means of hyoid bone, larynx
and the contraction of the thyrohyoid muscle.
 Further the epiglottis move over the laryngeal
vestibule.
 Hence the epiglottis guide the bolus into the
oesophagus.

9.  Aspiration of bolus into the airway is
prevented by several mechanism as follows-
1)Inhibition of respiration.
2)Elevation of larynx.
3)The piriform sinuses.

10.  When bolus reaches the upper end of the
oesophagus the upper oesophageal sphincter
contracts.
 This peristaltic movement causes the bolus to
entered into the stomach with the help of
gravity.
 The lower oesophageal sphincter opens to
allow the bolus into the stomach.

11.  It is possible to ingest fluid without oral
cavity.
 If the head is tipped back and the
oesophagus is in the straight pathway.
 The ingestion of fluid is same as the solids.

12.  31 paired muscle are involved.
 In oral phase-medial pterygoid, masseter and
temporalis are involved.
 Facial and lips and cheeks also helps and
maintained the mandibular stability.

13.  In pharyngeal phase-mylohyoid, geniohyoid,
palatopharyngeous, palatoglossus,superior
constrictor, styloglossus and stylohyoid.
 These are called leading complex.
 After activation of the leading complex the
middle and the inferior constrictor become
active.

14.  The process by which newborns and infants
feed is called suckling.
 Suckling consist of development of negative
pressure or suction in the oral cavity
combined with jaw movements.
 Infants can swallow without interruption of
breathing.

15.  When the posterior part of mouth is
stimulated a swallowing pattern of reflex is
set up.
 Any irritation or noxious stimulation can lead
to a vomiting reflex.
 If the swallowing reflex pattern could be
inhibited the mouth is held open and the
cricopharyngeal sphincter and the
nasopharynx are closed.

16.  Attempts are made to expel the stimulating
material from the mouth by movements of
the tongue.
 Which starts at the back of the mouth and
move forward this is known as gagging or
retching.