Swallowing 47

8/8/2019 Swallowing 47

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Deglutition(Swallowing)

Sitthichai Wanachantararak


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1/3 Teaspoon Honey Consistency


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Deglutition (Swallowing)

Figure 22.13a-c


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Involves the coordinated activity of the tongue, softpalate, pharynx, esophagus and 22 separate musclegroups

Buccal phase bolus is forced into the oropharynx

Pharyngeal-esophageal phase controlled by themedulla and lower ponso All routes except the one into the digestive tract are sealed off

Peristalsis moves food through the pharynx to theesophagus


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infantile (or immature) swallow

has the following characteristics:1. The jaws are apart, with the tongue between the gumpads;

2. The mandible is stabilized mainly by contraction of themuscles innervated by the VII (seventh) cranial nerve andthe interposed tongue;3. The swallow is guided and to a great extent controlled bysensory interchange between the lips and the tongue


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mature swallow

Usually, by 18 months of age, the following mature swallowcharacteristics are to be observed:1. The teeth are together;

2. The mandible is stabilized by contraction of the mandibularelevators, these being primarily innervated by the trigeminalnerve;3. The tongue tip is held against the palate above and behindthe incisors;

4. There are minimal contractions of the lips during themature swallow.


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Theories of deglutition

1.THEORY OF CONSTANT PROPORTION2.THEORY OF ORAL EXPULSION3.THEORY OF NEGATIVE PRESSURE

4.THEORY OF

INTEGR

AL

FUNCT

ION


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THEORY OF CONSTANT PROPORTION

1. Oral phase; the bolus is formed and transportedunder voluntary control to the pharynx;2. Pharyngeal phase; following receipt of the bolus,

the pharynx is activated to propel the food to theoesophagus;3. Oesophageal phase; passage of bolus down theoesophagus to the stomach by oesophageal

contraction


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THEORY OF INTEGRAL FUNCTION

based on cinefluorographic, myometric andelectromyographic studies, and considers that theact of deglutition is a total dynamic process. This is

the currently accepted theory


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THEORY OF INTEGRAL FUNCTION

Phases of the mature deglutition cycle1. Preparatory phase2. Oral phase

3. Pharyngeal phase4. Oesophageal phase


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1/3 Teaspoon Ground Meat and 1/4 Cookie


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1. Preparatory phase

starts as soon as liquids are taken into the oralcavity or after the bolus has been masticated.

The liquid or bolus is position on the dorsum of

the tongue, with the oral cavity sealed by the lipand the tongue.

The positioning of a liquid on the dorsum of thetongue before transporting it to the final

swallow-preparatory position may be facilitatedthrough suction created by moving the tongueposteriorly after a peripheral seal has beenestablished within the cavity.


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1. Preparatory phase

A final characteristic is the stabilization of the oralcavity

'Considerable pressure' is exerted between the

teeth in the molar region as the lip is elevated toposition the bolus in adult subjects, although it isapparent that in the predentition or mixed dentitionphases, other mechanisms would need to be used

for this purpose.


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2. Oral phase

introduced by the withdrawal of the soft palate from its restposition against the root of the tongue, where it is held bythe tensor palati muscles.

In this phase the soft palate moves upward and thetongue drops downward and backward.

At the same time, the larynx and hyoid move upward. The elevation of the hyoid may actually be initiated as the

bolus is positioned in the swallow-preparatory phase.


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2. Oral phase

These combined movements make a smooth pathfor the bolus as it is pushed from the oral cavity bythe peristaltic-Iike action of the tongue.

Solid food is actually pushed by the tongue,whereas fluids flow ahead of the lingualcontractions.

During this phase, the oral cavity maintains an

anterior and lateral seal, and is stabilized by themuscles of mastication.


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2. Oral phase

When a large bolus is to be swallowed, most or allof it is moved into the preparatory position and isthen neatly sectioned by the tongue in consecutive

swallows until the oral cavity is empty.


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3. Pharyngeal phase

This phase begins as the bolus passes from thetongue through the fauces.

The pharyngeal tube is raised and the

nasopharynx sealed by closure of the soft palateagainst the posterior pharyngeal wall.

Active participation of the pharynx is elicited by softpalate and bolus contact with the pharyngeal wall,

an action which consists of an elevation of theentire


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3. Pharyngeal phase

pharyngeal tube and a sphincteric reduction in the lumenbetween the upper pharyngeal wall and soft palate.

The hyoid and the base of the tongue move forward as

both the tongue and the pharynx continue their peristaltic-like action on the food bolus. Passage of such a bolus through the pharynx during the

mature swallowing is enhanced by an anterior movementof the hyoid and root of the tongue.


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3. Pharyngeal phase

Finally, there is an abrupt elevation of the larynx asthe bolus reaches the laryngo-pharynx and, this isthen followed by elevation of the floor of the

laryngophary and opening of the oesophagealsphincter.


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4. Oesophageal phase

This phase commences as soon as food passesthe cricopharyngeal sphincter. While peristalticmovement carries the food through the

oesophagus, the hyoid bone, soft palate andtongue return to their'original positions'.


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Figure 22.13d, e


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Esophagus

Peristalsis:o Produced by a series of

localized reflexes inresponse to distention ofwall by bolus.

Wave-like muscularcontractions:o Circular smooth muscle

contract behind, relaxesin front of the bolus.

o Followed by longitudinalcontraction (shortening)of smooth muscle. Rate of 2-4 cm/sec.

o After food passes intostomach, LES constricts.

Insert 18.4a


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Most distensible part of GI tract.o Empties into the duodenum.

Functions of the stomach:o Stores food.o Initiates digestion of proteins.o Kills bacteria.o Moves food (chyme) into intestine.

Stomach


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Conclusion for swallowing


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Oral Preparatory Phase

tongue positions material on the teeth rotary lateral movement of the mandible and tongue

during mastication

tongue moves the material back onto the teeth as themandible opens after cycle is repeated numerous times, a bolus is formed during active chewing, the soft palate is not pulled down

and forward and premature spillage is common and

entirely normal


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Oral Preparatory Phase


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Pharyngeal Phase

elevation and retraction of the velum and completeclosure of the velopharyngeal to prevent passageinto the nasopharynx

elevation and anterior movement of the hyoid andlarynx

closure of the larynx at the true vocal folds, thelaryngeal entrance and the epiglottis to prevent

material from entering the airway


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Pharyngeal Phase


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Second swallow

A second swallow was needed to clear all the material 1/3 Teaspoon Ground Meat and 1/4 Cookie In this

segment, please note: The rotary lateral movement of the mandible and tongue The formation of the bolus During chewing, the soft palate is not pulled down and

forward and material falls into the pharynx partially beforethe pharyngeal phase is triggered

Bolus size decrease with the viscosity of food; J.P.swallowed twice on the ground meat material


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Second swallow


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Control of deglutition


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Control of deglutition


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Speech

1 Speech Mechanism Physiological phonetics All sounds which come from the mouth and nose

arethe result of interruptions and/or modificationsof a stream of air moving from the lungs through:

trachea - larynx pharynx - oral cavity nasal cavity


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4 speech process

respiration phonation

resonation articulation*


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Articulation

structures of pharynx, nasal and oral cavity way of modifying airstream articulation = joining together of speech organs for

production of phonemes


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lips

supported by maxilla (upper jaw) and lower jaw(mandible)

Body function - receive and contain food

Speech function - varied movement: rounded,tensed: obstruct air flow


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teeth body function - cut and grind food

speech function - anatomical obstacle for lips ortongue

alveolar ridge (gum ridge of maxilla body function - none; houses teeth speech function - point of contact/constriction


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hard palate - bony structure posterior to alveolarridge

body function - contain food in oral cavity

speech function - point of contact; defines shape oforal cavity


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soft palate/velum - muscular structure posterior tohp

body function - separate oral cavity and nasal

cavity speech function - direction of air flow -open/closevp port: point of contact


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tongue -major articulator/ muscle and mobile body function - direct food to back of oral cavity speech function - direction of air flow: contacts


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other structures

: approximates other structures; changes size of oral cavity mandible

body function - chewing

speech function - change size of oral cavity


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Oral cavity from mouth opening to posterior wall of pharynx(posterior pharyngeal wall)

body function: breathing, eating speech: channels airstream: contributes oralresonance Nasal cavity - extends from nostrils (nares) to

posterior


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Pharynx posterior portion of nasal cavity down through backof oral cavity to larynx

body function: breathing

speech: contributes nasal resonance Vocal cords/folds

in lateral walls of larynx body function: respiratory protection

phonation


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Thank you for your attention

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Swallowing 47