Physiology of Mastication and Deglutition Flashcards
Mastication
-prep of food for swallow
-involves oral muscles, teeth, all articulators
Deglutition
-swallowing
Dysphagia
-disorders of swallowing at any stage in process
Cricopharyngeus
-component of inferior constrictor involved in upper esophageal sphincter (UES)
Pharyngoesophageal (PE Segment)
-upper esophageal sphincter, immediate esophageal region, and immediate pharyngeal region
Infant Oral/Pharyngeal Space: Differences in Structure
-oral cavity smaller
-larynx higher descends during first 4 years
-hyoid elevated and forward
-velum large compared to pharynx
-no teeth
Infant Oral/Pharyngeal Space: Function of Differences in Structures
-large velum, large tongue, elevated larynx significant part in respiration and deglutition
-structural differences important for nipple feeding
-small mandible and large tongue important for piston like tongue movement for sucking
-high larynx protect airway by allowing tighter oral seal for sucking
-facilitating simultaneous breathing, swallowing, and sucking
-prevents food and liquid from entering trachea
Developmental Issues in Neonates: Tongue
-fills oral cavity
Developmental Issues in Neonates: Cheeks
-cheeks fat pads narrow oral cavity laterally
Developmental Issues in Neonates: Hyoid and Larynx
-both elevated
-provides natural protection of airway
Developmental Issues in Neonates: Velum
-hangs lower
-depressed during nursing
Developmental Issues in Neonates: Epiglottis
-visible, higher
Developmental Issues in Neonates: Uvula
-rests inside epiglottis forming pockets in valleculae
Valleculae
two depression in throat between base of tongue and epiglottis
Developmental Issues in Neonates: Bolus
-tends to collect at back of tongue while swallowing
Developmental Issues in Neonates: Teeth
-no teeth
Developmental Issues in Neonates: Mastication
-no mastication
Infant Growth: Jaw
grows down and forward
Infant Growth: Oral Cavity
-grows
Infant Growth: tongue
-descends
-ceases anterior movement during swallowing
-results in adult oral/pharyngeal system
Infant Growth: hyoid, larynx, epiglottis
all drop
Infant Growth: Pharynx
enlarges to compensate for drop of hyoid, larynx, and epiglottis
Infant Growth: Teeth
erupt
Infant Growth: most enlargement
-during puberty
Infant Growth: face
-continues to grow until 21 years old
Suckling
-piston like movements of tongue with tongue cupping
-tongue protrudes
-presses on breast, extrudes milk
-generally reflexive
-tongue protrusion natural at this stage
Sucking
-tongue raises and lowers as protrudes and retracts
-strong labial seal
-milk drawn into oral cavity
Infant Swallowing
-begins in fetus with sucking movements
-fetus drinks amniotic fluid: thumb in mouth
Neonate Swallowing
-repeatedly pumps tongue: tongue and jaw together initially
-liquid collects at fauces or valleculae
-uses 2-7 tongue pumps before swallow
-adequate bolus triggers pharyngeal swallow
-apneic period during swallowing
Apneic Period
-newborn must coordinate sucking, swallowing, and breathing
-early: 3 sucks then swallow while suspending respiration
-later: 1 suck then swallow
-can range between 10-30 sucks in duration
Chewing Critical Period: 6 months of age
-development of skills due to plasticity of nervous system
-experience promotes remodeling of neutral circuits that control movements
Chewing Critical Period: Beginning approx. 4 months
-respond to taste that shape motor function
-eruption of dentition supports mastication via sensory awareness of chewing process
Infant: Mastication
-Bite achieved by 7 months
-chewing begins at 10-12 months
-normal chewing established by 4 years
-by time child swallows pureed or soft food: adult form except less elevation
Presbyphagia
-age related changes in swallowing not classified as dysphagia
Sarcopenia
-as age all muscles weaken and get slower
-produces reduction in transit times and force generation in swallowing: causes prolonged oral prep and oral stages
Aging: Reduced Sensation
-causes less brisk and robust reflexes: including protective reflexes
Older Adults: Mastication
-if dentition complete maintain good mastication
-see more chewing strokes as get older: as teeth go bad, if dentures do not fit well
Older Adults: Deglutition
-laryngeal cartilages ossification makes easier to see swallow studies
-after 70 years larynx lowers
-cervical arthritis may occur
-may decrease flexibility of pharynx, reduce strength of pharynx, may need second swallow to clear
Age Does Not Protect Aspiration: Penetration
-introduction of bolus into laryngeal aditus
-penetration increases with age but no increase in aspiration
Age Does Not Protect Aspiration: Aspiration
-introduction of bolus past vocal folds
Age Does Not Protect Aspiration: 20-30 yrs old vs 80-96 yrs old
-reduced maximal laryngeal and hyoid movement
-reduced neuromuscular reserve
-reduced elevation and UES opening
Stages of Swallow
-oral stage: oral prep, oral transit
-pharyngeal
-esophageal
Oral Prep: Anticipation Food
-perceptual olfactory and visual provides motivation to ingest
Oral Prep: Food presented and mouth opens to receive food
-preparatory phase
Oral Prep: Tongue
-cups in anticipation
Oral Prep: Lips
-may be used to clear spoon
Oral Prep: Teeth
-may be used to clear fork
Oral Prep: Lips, Tongue, Velum
-lips sealed
-tongue rises in rear
-velum drops to keep food in oral cavity which allows nasal breathing
Oral Prep: Food Bolus
-must be ground up to pass through esophagus
-reduction phase
Oral Prep: Tongue response for keeping food in oral cavity
creates seal along alveolar ridge
Oral Prep: Tongue can also compress food against hard palate
-partially crushing prepare for teeth
Oral Prep: Tongue Moves Food
-tongue moves food to molars for additional grinding
Oral Prep: Grinding Action
-crushes food
-action milks salivary glands
Oral Prep: Food Pulled back
-food pulled back into oral cavity to mix saliva with food
Oral Prep: Tongue returns bolus
-tongue returns bolus to molars for additional grinding
Oral Prep: Facial Muscles
-facial muscles of buccal wall (risorius and buccinator) contact to prevent food from entering lateral sulcus
Oral Prep: Move Bolus
-move bolus onto tongue to test consistency
-if not desired consistency, move back to molars
-when desired consistency initiate swallowing
Oral Transit
-swallowing “initiation stage”
Oral Transit: Tip of tongue to raise alveolar ridge and hyoid elevates
-vocal folds close 0.1 seconds after initiation to stop breathing
-hyoid elevation may be part of pharyngeal stage
Oral Transit: Tongue Tip and Dorsum
-tongue tip and dorsum squeeze bolus to faucial pillars
Oral Transit: Tippers
-some raise tongue during swallowing
Oral Transit: Dippers
-some lower tongue during swallowing
Oral Transit: Mandible
-elevates to counteract pressure of tongue to roof of mouth
Oral Transit: Velum
-remains depressed to keep bolus in oral cavity
Oral Transit: Bolus, faucial pillars, and soft palate
-either or both trigger pharyngeal stage
Oral Transit: Adequate Bolus
-adequate bolus required in oropharynx initiate pharyngeal stage
Pharyngeal Stage Airway Protection: as bolus moves down, airway protected
-tip of tongue to raise to alveolar ridge elevates hyoid
-true vocal folds adduct: aka leading complex
-larynx elevates
-false folds adduct
-lower vestibule closes via arytenoids pulling medially and anteriorly
-upper vestibule closes via epiglottis dropping down after aditus
Pharyngeal Stage Pharynx Pressurization: Pressure developed through coordianted muscle contractions
-primarily tongue and pharyngeal constrictirs muscles
Pharyngeal Stage Pharynx Pressurization: Tongue Action
-tongue presses against hard palate generation pressure wave that propels bolus into oropharynx
Pharyngeal Stage Pharynx Pressurization: Pharyngeal Constrictor Muscles
-contract sequentially, creating a peristaltic wave that increases pressure and pushes bolus down pharynx
Pharyngeal Stage Pharynx Pressurization: Soft Palate Elevation
-contracts lateral and posterior pahryngeal walls closes nasopharynx
-increasing pressure
-prevents food from entering nasal cavity
Pharyngeal Stage Pharynx Pressurization: Hyoid and larynx elevate and move forward
-creates lower pressure at esophageal entry
Pharyngeal Stage Pharynx Pressurization
-relaxation of cricopharyngeus muscle superior to inferior pressure gradient
Pharyngeal Stage: Bolus Movement (Tongue)
-moves posteriorly and carries bolus to oropharynx
Pharyngeal Stage: Bolus Movement (Pharynx)
-elevates
-contracts in peristaltic wave pushes bolus downward
Pharyngeal Stage: Bolus Movement (Pressure)
-pressure drives bolus inferiorly
Pharyngeal Stage: Bolus Movement (Bolus passes through)
-bolus passes through phryngoesophageal (PE) and clears larynx
Pharyngeal Stage: Bolus Movement (PE Segment)
closes
Pharyngeal Stage: Bolus Movement (Larynx)
lowers
opens superior to inferior
Pharyngeal Stage: Bolus Movement (Velum)
lowers
Pharyngeal Stage: Bolus Movement (Expiration Occurs)
-blows residues from larynx aditus
Infant Pharyngeal Swallow Same As Adult
-except
-larynx less elevation
-posterior pharyngeal walls moves forward more than adults
-airway can be open: always apneic period
Geriatric Individuals: Oral Stage
-generally weaker
-tend hold bolus on floor of mouth
-tend to pick bolus up with tongue tip
-oral stage little longer than adults: chew more
Geriatric Individuals: Pharyngeal Stage
-increased delay triggering pharyngeal swallow due to loss in sensation
-delay increases with bolus size and age
-<30 yrs = 0.1 sec
-30-59 yrs = 0.3 sec
-60 yrs = 0.4 sec
Esophageal Phase
-initiates when bolus enters esophagus
-triggered of upper 2 cm of esophagus by bolus
-bolus triggered to lower esophageal segments (LES): transit via peristalsis of smooth and striated muscle and gravity
-approx 2 secs from UES to LES
-enters stomach for digestion
Geriatric Individual Esophageal Phase
-esophageal function deteriorates significantly with age: slower and less efficient
Geriatric Individual Esophageal Phase: 80-96 yrs
-reduced laryngeal and hyoid movement: reduced neuromuscular reserve
-limits cricopharyngeal opening
-in younger, have greater elevation as volume increases: not seen in elderly
