1. Deglutition, or swallowing, is the process by which food moves from the mouth to the stomach through coordinated muscular contractions.
2. It involves three stages - oral, pharyngeal, and esophageal. The oral stage is voluntary while the pharyngeal and esophageal stages are involuntary.
3. During the pharyngeal stage, the bolus is pushed from the oropharynx to the hypopharynx through tongue and pharyngeal muscle contractions before entering the esophagus. The esophageal stage then transports the bolus to the stomach through peristaltic waves.
2. INTRODUCTION:-
* Deglutition or swallowing is the process by which
food moves from mouth into stomach
*Swallowing consist of voluntary, involuntary and
reflex muscular activity.
*Over a period of 24 hours swallowing occurs
approximately 1000 times; which is highest while
eating.
*Deglutition involves co-ordinate activity of muscles
of oral cavity, pharynx, larynx and esophagus
3. DEFINITION
*Complex series of voluntary and involuntary
neuromuscular contraction proceeding from the
mouth to stomach and is commonly divided in to
oropharyngeal & esophageal stage.
4. THEORIES OF DEGLUTITION
1.Theory of oral expulsion:-
*This theory state that, the oral expulsion
arising from contraction of tongue & mylohyoid
throws bolus into the stomach.
5. 2.Theory of integral function:-
*this theory is based on myometric and
electromyographic studies & considers the act
of swallowing as a dynamic process.
*it is most accepted theory.
6. COMPONENTS OF DEGLUTITION:-
*Deglutition has 3 components
1.Passage of bolus from oral cavity to stomach.
2.Protection of airway.
3.Inhibition of air entry into the stomach.
9. ORAL STAGE
* This stage food moves from mouth to
pharynx
*This stage of deglutition is a voluntary
stage.
*Bolus is placed over posterodorsal surface
of the tongue . it is called preparatory
position.
10. * Anterior part of tongue is retract and depressed.
*Posterior part of tongue is elevated and retracted
against the hard palate.
This pushes the bolus backward into the pharynx.
*During this phase, airway is open and breathing
continues normally.
*The oral phase of deglutition takes around 0.5
seconds.
11. PHARYNGEAL STAGE
*It is a involuntary stage.
*This stage food moves from pharynx to esophagus.
*The bolus is transported from the oropharynx into
esophagus by a peristaltic wave caused by contraction of
the pharyngeal constrictor muscle.
*Pharynx is a common passage for food and air. it divide
into larynx and esophagus.
*The pharyngeal phase of deglutition takes around 0.7
seconds.
12. *Pharynx communicates with mouth, nose, larynx
and esophagus, during this stage of deglutition.
*the pharyngeal phase tongue makes a rapid piston-
like movement to propel the bolus through
oropharynx to hypopharynx.
*The glosso-pharyngeal nerve(IX) and the pharyngeal
branches of the vagus (x) innervate the pharynx and
larynx, and co-ordinate into swallowing centre in the
brain stem.
13.
14. *This stage is Involuntary stage.
*In this stage food moves from esophagus to
stomach.
*Esophagus forms the passage for movement of
bolus from pharynx to the stomach.
*this phase is somewhat longer, liquids take 3
seconds whereas solid take 9 seconds.
ESOPHAGEAL STAGE
15. *Movements of esophagus are specifically
organized for this function and the movements
are called peristaltic waves.
*Peristalsis means a wave of contraction,
followed by the wave of relaxation of muscle
fibers of GIT.
16.
17. *When bolus reaches the esophagus, the peristaltic
wave are initiated.
*usually two types of peristaltic contraction are
produced in esophagus:-
1.Primary peristaltic contraction.
2.Secondary peristaltic contraction.
18. *The distal 2-5mm is the lower esophageal
sphincter.
*when bolus enters this part of esophagus, the
sphincter relaxes and the contents enter into
stomach.
*later this sphincter contract to prevent
movement of food back to esophagus.
19. DEGLUTITION REFLEX
*Though the beginning of swallowing is a
voluntary act, later it becomes involuntary and
is carried out by a reflex action called
deglutition reflex.
*It occurs during the pharyngeal and
esophageal stages.
20. FEATURES OF INFANTILE SWALLOW
*mandible is stabilized by both tongue and
facial muscles which are supplied by the 7th
cranial nerve.
*Because of anatomic relationship of new born
pharynx and larynx, infants can swallow
without interruption of breathing.
21. FEATURES OF ADULT SWALLOW:-
*Mandible is stablized by occluding teeth and
masticatory muscles which are supplied by the 5th
cranial nerve.
*temporary arrest of respiration is observed during
swallowing.
22. APPLIED PHYSIOLOGY
1.DYSPHAGIA:-
*Difficulty in swallowing.
TYPES-
1.Oropharygeal dysphagia
2.Esophageal dysphagia
Causes-
*Decreased movement of esophagus due to
neurological disorder such as parkinsonism.
*Muscular disorders leading to difficulty in
swallowing.
23. 2.DEGLUTITION APNEA:-
*Apnea refers to temporary arrest of
breathing.
*Deglutition apnea or swallowing apnea is
the arrest of breathing during deglutition.