Ch. 9 Physiology of Mastication and Deglutition. Introductory Terms Dysphagia: A disorder of...

Ch. 9Ch. 9

Physiology of Mastication Physiology of Mastication and Deglutition and Deglutition

Introductory TermsIntroductory Terms

Dysphagia: A disorder of swallowingDysphagia: A disorder of swallowing Bolus: ball of food or liquid to be swallowedBolus: ball of food or liquid to be swallowed

Mastication: the process of preparing food for Mastication: the process of preparing food for swallowing swallowing • Moving food onto the grinding surfaces of the teeth Moving food onto the grinding surfaces of the teeth • ChewingChewing• mixing it with saliva in preparation for swallowing mixing it with saliva in preparation for swallowing

Deglutition: the process of swallowingDeglutition: the process of swallowing• Both the two above concepts require integration of Both the two above concepts require integration of

lingual, velar, pharyngeal, facial muscle movement, lingual, velar, pharyngeal, facial muscle movement, laryngeal adjustments, respiratory controllaryngeal adjustments, respiratory control

Introductory TermsIntroductory Terms Perioral region: around the mouthPerioral region: around the mouth Rooting Reflex: reflexive response of infant to Rooting Reflex: reflexive response of infant to

tactile stimulation of the cheek or lips, infant tactile stimulation of the cheek or lips, infant turns toward stimulus, opens mouthturns toward stimulus, opens mouth

Sucking Reflex: tongue protrusion and retraction Sucking Reflex: tongue protrusion and retraction in preparation for receipt of liquid; stimulated by in preparation for receipt of liquid; stimulated by contact to the upper lipcontact to the upper lip

Esophageal Reflux: esophageal regurgitation into Esophageal Reflux: esophageal regurgitation into the hypopharynxthe hypopharynx

Nasal regurgitation: loss of food or liquid through Nasal regurgitation: loss of food or liquid through the nosethe nose

Peristaltic: WavelikePeristaltic: Wavelike

Introductory TermsIntroductory Terms

Oral Transit Time: time required to Oral Transit Time: time required to move the bolus to the point of move the bolus to the point of initiation of the pharyngeal stage of initiation of the pharyngeal stage of swallowingswallowing

Pharyngeal Transit Time: time Pharyngeal Transit Time: time required to move the bolus from the required to move the bolus from the beginning of pharyngeal swallow to beginning of pharyngeal swallow to the time the bolus enters the the time the bolus enters the esophagusesophagus

Organizational PatternsOrganizational Patterns

Oral Preparatory StageOral Preparatory Stage• Stage in which food is prepared for swallowStage in which food is prepared for swallow

Oral StageOral Stage• Bolus transmitted to pharynxBolus transmitted to pharynx

Pharyngeal StagePharyngeal Stage• Bolus transmitted to the esophagusBolus transmitted to the esophagus• Numerous physiological responsesNumerous physiological responses

Esophageal StageEsophageal Stage• Food is transported from the upper esophageal Food is transported from the upper esophageal

region to the stomach region to the stomach

Deficit PatternsDeficit Patterns Oral Preparatory StageOral Preparatory Stage

• Neuromuscular deficitsNeuromuscular deficits Loss of sensation and awarenessLoss of sensation and awareness Weak buccal musculatureWeak buccal musculature Weak muscles of mastication may cause Weak muscles of mastication may cause

inadequqtely chewed foodinadequqtely chewed food Weak lingual muscles may cause poor mixture of Weak lingual muscles may cause poor mixture of

saliva with food, inadequate bolus production, saliva with food, inadequate bolus production, difficulty compressing bolus onto hard palatedifficulty compressing bolus onto hard palate

Weak soft palate muscles may cause the velum to Weak soft palate muscles may cause the velum to not be fully depressed, tongue not adequately not be fully depressed, tongue not adequately elevated in back, permitting food to escape into the elevated in back, permitting food to escape into the pharynx prior to initiation of pharyngeal reflexespharynx prior to initiation of pharyngeal reflexes

Food entering pharynx prior to a reflexive response Food entering pharynx prior to a reflexive response may reach the open airway and produce an may reach the open airway and produce an aspiration pneumoniaaspiration pneumonia

Deficit PatternsDeficit Patterns

Oral StageOral Stage• Sensory and Motor dysfunctionSensory and Motor dysfunction

Weakened movements cause reduced Weakened movements cause reduced oral transit time, fodd may remain on oral transit time, fodd may remain on tongue and hard palate following tongue and hard palate following transittransit

Epiglottis fail to invert over laryngeal Epiglottis fail to invert over laryngeal opening, limited elevation of the opening, limited elevation of the hyoid, may be increased pooling of hyoid, may be increased pooling of food or liquid in the valleculaefood or liquid in the valleculae

Difficulty initiating a reflexive swallow Difficulty initiating a reflexive swallow may be due to a sensory deficit may be due to a sensory deficit

Deficit PatternsDeficit Patterns Pharyngeal StagePharyngeal Stage

• Sensory and Motor DysfunctionSensory and Motor Dysfunction Slow velar elevation may result in nasal regurgitationSlow velar elevation may result in nasal regurgitation Reduced sensation of fauces, posterior tongue, Reduced sensation of fauces, posterior tongue,

pharyngeal wall, soft palate may cause elevated pharyngeal wall, soft palate may cause elevated threshold for trigger of swallowing reflexthreshold for trigger of swallowing reflex

Reduced function of pharyngeal constrictors may Reduced function of pharyngeal constrictors may result in slowed pharyngeal transit time of bolus and result in slowed pharyngeal transit time of bolus and individual may reinitiate respirationindividual may reinitiate respiration

Weakened pharyngeal function may result in residue Weakened pharyngeal function may result in residue left in the valleculaeleft in the valleculae

Failure of the hyoid and thyroid to elevate may result Failure of the hyoid and thyroid to elevate may result in loss of airway protection, food may fall into larynx in loss of airway protection, food may fall into larynx and be aspirated on breathingand be aspirated on breathing

Deficit PatternsDeficit Patterns

Esophageal StageEsophageal Stage• GERD: acids from the stomach flow to GERD: acids from the stomach flow to

the esophagus and pharynx, may be the esophagus and pharynx, may be UES or LES problem or bothUES or LES problem or both

• Hiatal Hernia: LES may malfunction Hiatal Hernia: LES may malfunction allowing reflux into esophagusallowing reflux into esophagus

• Congenital Malformation: stenosis, see Congenital Malformation: stenosis, see figure 9-4 figure 9-4

Neurophysiological TermsNeurophysiological Terms Taste Buds (cells): chemoreceptors for gustationTaste Buds (cells): chemoreceptors for gustation Chemoreceptors: Neural receptors that respond to specific chemical Chemoreceptors: Neural receptors that respond to specific chemical

compositioncomposition Papillae: ProminencesPapillae: Prominences Taste Pore: opening in lingual epithelium that houses taste cellTaste Pore: opening in lingual epithelium that houses taste cell Microvilli: small, hairlike fibers projecting from the taste cell into the Microvilli: small, hairlike fibers projecting from the taste cell into the

taste poretaste pore Mechanoreceptors: neural receptors designed to sense mechanical Mechanoreceptors: neural receptors designed to sense mechanical

forcesforces Glabrous: HairlessGlabrous: Hairless Meissner’s Corpuscles: Superficial cutaneous mechanoreceptors for Meissner’s Corpuscles: Superficial cutaneous mechanoreceptors for

minute movementminute movement Merkel disk receptors: Superficial cutaneous mechanoreceptors for Merkel disk receptors: Superficial cutaneous mechanoreceptors for

light pressurelight pressure Pacinian Corpuscles: deep cutaneous mechanoreceptors for deep Pacinian Corpuscles: deep cutaneous mechanoreceptors for deep

pressurepressure Ruffini endings: deep cutaneous mechanoreceptors for tissue stretchRuffini endings: deep cutaneous mechanoreceptors for tissue stretch Nociceptors: Pain sensorsNociceptors: Pain sensors Salivation: Production and release of saliva into to oral cavitySalivation: Production and release of saliva into to oral cavity Mucus: Thick, high-viscosity salivaMucus: Thick, high-viscosity saliva Serous:Thin, low viscosity saliva Serous:Thin, low viscosity saliva

NeurophysiologyNeurophysiology

GustationGustation• Taste receptors (taste buds, taste cells)Taste receptors (taste buds, taste cells)• Class of sensors known as chemoreceptorsClass of sensors known as chemoreceptors

Found within the epithelia of the with in papillae or Found within the epithelia of the with in papillae or prominencesprominences

Taste pour: opening in lingual epithelium that Taste pour: opening in lingual epithelium that houses taste cell, permits isolation of the tasted houses taste cell, permits isolation of the tasted substancesubstance

Microvilli: small hairlike fibers projecting from the Microvilli: small hairlike fibers projecting from the taste cell into the taste pore, holds sample of food taste cell into the taste pore, holds sample of food in taste porein taste pore


GustationGustation• Taste mediated by 3 cranial nervesTaste mediated by 3 cranial nerves

V!! mediates sense of taste from anterior 2/3 of the tongue, V!! mediates sense of taste from anterior 2/3 of the tongue, sweet and sour sensations, and of palate. Sides transmit salt sweet and sour sensations, and of palate. Sides transmit salt and sour.and sour.

IX mediates sense of taste, primarily of bitterness from IX mediates sense of taste, primarily of bitterness from

posterior 1/3 of tongue. Sides transmit salt and sourposterior 1/3 of tongue. Sides transmit salt and sour X mediates sense of taste from epiglottis and esophagus X mediates sense of taste from epiglottis and esophagus Umami: taste receptor which processes monosodium Umami: taste receptor which processes monosodium

glutamate.glutamate.


GustationGustation• Taste VII CNTaste VII CN

Taste receptorTaste receptor Geniculate ganglionGeniculate ganglion Medullary solitary tract (NST)Medullary solitary tract (NST) Rostral and lateral aspects of ST nucleus for gustationRostral and lateral aspects of ST nucleus for gustation Ventral posterior medial nucleus of thalamusVentral posterior medial nucleus of thalamus Information relayed ipsilaterally to the sensory cortex (post Information relayed ipsilaterally to the sensory cortex (post

central gyrus),anterior portion of the insula of the cerebral central gyrus),anterior portion of the insula of the cerebral cortex, and to the operculum overlying the insula.cortex, and to the operculum overlying the insula.


GustationGustation• Taste IX CNTaste IX CN

Taste receptorTaste receptor Petrosal ganglionPetrosal ganglion Medullary solitary tract (ST)Medullary solitary tract (ST) Rostral and lateral aspects of ST nucleus for gustationRostral and lateral aspects of ST nucleus for gustation Ventral posterior medial nucleus of thalamusVentral posterior medial nucleus of thalamus Information relayed ipsilaterally to the sensory cortex (post Information relayed ipsilaterally to the sensory cortex (post



GustationGustation• Taste X CN (epiglottal and esophageal)Taste X CN (epiglottal and esophageal)

Taste receptorTaste receptor Nodose ganglionNodose ganglion Rostral and lateral aspects of ST nucleus for gustationRostral and lateral aspects of ST nucleus for gustation Ventral posterior medial nucleus of thalamusVentral posterior medial nucleus of thalamus Information relayed ipsilaterally to the sensory cortex (post Information relayed ipsilaterally to the sensory cortex (post


Taste and small probably integrated in the insulaTaste and small probably integrated in the insula Fibers from the insula project to the limbic and motor Fibers from the insula project to the limbic and motor

regions of the brainstemregions of the brainstem


GustationGustation• NTS projects to the motor cortex, specifically NTS projects to the motor cortex, specifically

area serving the tonguearea serving the tongue Tastes (sweet {carbohydrates}, protein {umami} Tastes (sweet {carbohydrates}, protein {umami}

salt) will elicit salivation, ingestive responsessalt) will elicit salivation, ingestive responses• Tongue protrusion to receive the foodTongue protrusion to receive the food• Release of insulinRelease of insulin• Mastication and deglutitionMastication and deglutition



area serving the tonguearea serving the tongue Tastes, bitter and sour mat typify poison and elicit Tastes, bitter and sour mat typify poison and elicit

a protective responsea protective response• GaggingGagging• CoughingCoughing• ApneaApnea• Salivation (encapsulates the material and protects the Salivation (encapsulates the material and protects the

oral cavityoral cavity



area serving the tonguearea serving the tongue Taste can elicit motor responses that may or may Taste can elicit motor responses that may or may

not be under volitional controlnot be under volitional control• Gag responseGag response

Elevation of the larynxElevation of the larynx Clamping of the vocal foldsClamping of the vocal folds Elevation of the velumElevation of the velum Protrusion of the tongueProtrusion of the tongue



area serving the tonguearea serving the tongue Taste can elicit motor responses that may or may Taste can elicit motor responses that may or may

not be under volitional controlnot be under volitional control• CoughingCoughing

Tightly closing VF and supraglottic structuresTightly closing VF and supraglottic structures Compressing of abdomen and thoraxCompressing of abdomen and thorax Forcefully blowing VF apartForcefully blowing VF apart


GustationGustation• Deglutition is made up of a complex set of Deglutition is made up of a complex set of

motor responses dictated by stimuli present motor responses dictated by stimuli present in the oral and pharyngeal spacesin the oral and pharyngeal spaces

Explain this Explain this


OlfactionOlfaction• Olfactory chemoreceptors in nasal mucus membraneOlfactory chemoreceptors in nasal mucus membrane• Sense of smell transmitted to olfactory bulb in cranial Sense of smell transmitted to olfactory bulb in cranial

spacespace• Then transmitted over olfactory tract to olfactory Then transmitted over olfactory tract to olfactory

region of the cortex, and from some to the thalamusregion of the cortex, and from some to the thalamus Amygdala to hypothalamusAmygdala to hypothalamus Anterior olfactory nucleusAnterior olfactory nucleus Piriform cortexPiriform cortex Olfactory tubercleOlfactory tubercle Entorhinal cortex to hippocampus in the temporal lobeEntorhinal cortex to hippocampus in the temporal lobe


OlfactionOlfaction• Arrives at cerebral cortex through multiple Arrives at cerebral cortex through multiple

pathways and serves as a stimulus topathways and serves as a stimulus to Emotion and motivation (amygdala)Emotion and motivation (amygdala) Physiological responses (hypothalamus)Physiological responses (hypothalamus) Memory encoding (hippocampus)Memory encoding (hippocampus) Olfactory discrimination (orbitofrontal region of Olfactory discrimination (orbitofrontal region of

the cerebral cortex)the cerebral cortex)


Tactile SenseTactile Sense• In face and oral cavity, primarily mediated by V, but In face and oral cavity, primarily mediated by V, but

IX and X are associatedIX and X are associated• Mechanoreceptors are sensative to physical contact, Mechanoreceptors are sensative to physical contact,

receptors vary according to type of touchreceptors vary according to type of touch• Deep pressure has the potential to stimulate a larger Deep pressure has the potential to stimulate a larger

field and greater array of sensors than light pressure, field and greater array of sensors than light pressure, an issue that is important in treatment of dysphagiaan issue that is important in treatment of dysphagia

• Vibration sense is a subclass of tactile senseVibration sense is a subclass of tactile sense Best FrequencyBest Frequency: The frequency if vibration at which a : The frequency if vibration at which a

sensor responds most effectively sensor responds most effectively


Thermal Receptors Thermal Receptors • In face and oral cavity, primarily mediated by V, but In face and oral cavity, primarily mediated by V, but

IX and X are associatedIX and X are associated• Same as pain sensors, bare nerve endingsSame as pain sensors, bare nerve endings• Differentiate warm, hot, cool, cold: receptors are Differentiate warm, hot, cool, cold: receptors are

tuned to particular temperaturestuned to particular temperatures• Have a tonic, ongoing chargeHave a tonic, ongoing charge• With high temperatures, heat sensors stop firing and With high temperatures, heat sensors stop firing and

pain sensors firepain sensors fire Perception of pain can interfere with the ability to swallow Perception of pain can interfere with the ability to swallow

and swallowing responsesand swallowing responses


Muscle stretch and Tension senseMuscle stretch and Tension sense• In face and oral cavity, primarily mediated by V, but In face and oral cavity, primarily mediated by V, but

IX and X are associatedIX and X are associated• Stretch receptors are found in oral musclesStretch receptors are found in oral muscles

MasseterMasseter TemporalisTemporalis Lateral and medial PterygoidLateral and medial Pterygoid GenioglossusGenioglossus palatoglossuspalatoglossus

• Muscle Spindle fibers (MSF)Muscle Spindle fibers (MSF) Return a muscle to its original position following passive Return a muscle to its original position following passive

stretching (pulling down on relaxed jaw)stretching (pulling down on relaxed jaw) MSF designed to maintain a muscle at a preset lengthMSF designed to maintain a muscle at a preset length MSF generally inhibited during active contractionMSF generally inhibited during active contraction


Muscle stretch and Tension senseMuscle stretch and Tension sense• Muscle TensionMuscle Tension

Sensed by Golgi tendon organs (GTOs) within tendons and Sensed by Golgi tendon organs (GTOs) within tendons and faciafacia

Muscle toneMuscle tone• Perception of resistance to passive movement of a stretchingPerception of resistance to passive movement of a stretching• regulated partially through interaction of muscle spindles and regulated partially through interaction of muscle spindles and

GTOs GTOs • High tone of spasticity due to inadequately inhibited response High tone of spasticity due to inadequately inhibited response

from a muscle spindle sensorfrom a muscle spindle sensor• Low tone results from inadequate tonic stimulation either LMN Low tone results from inadequate tonic stimulation either LMN

disease or cerebellar lesiondisease or cerebellar lesion• Muscular rigidity results from a basal ganglia lesion and Muscular rigidity results from a basal ganglia lesion and

demonstrates a cocontraction of agonist and antagonist demonstrates a cocontraction of agonist and antagonist


Salivation ResponseSalivation Response Not a sensory system but rather a motor responseNot a sensory system but rather a motor response Product of 3 glands: parotid, sublingual, Product of 3 glands: parotid, sublingual,

submandibularsubmandibular• Stimulation of taste receptors on anterior 2/3 of tongue Stimulation of taste receptors on anterior 2/3 of tongue

mediated by VII via NS of dorsal pons (sublingual and mediated by VII via NS of dorsal pons (sublingual and submandibular glands)submandibular glands)

• Stimulation of taste receptors on posterior 1/3 of tongue Stimulation of taste receptors on posterior 1/3 of tongue mediated by IX via inferior and superior salivatory nuclei mediated by IX via inferior and superior salivatory nuclei of the pons (parotid gland) of the pons (parotid gland)


Salivation ResponseSalivation Response Parotid produces Parotid produces Sublingual: produces mucus, a high-viscosity Sublingual: produces mucus, a high-viscosity

protein rich secretion that helps in formation of protein rich secretion that helps in formation of the bolus for foodthe bolus for food

Submandibular: produces serous (low viscosity, Submandibular: produces serous (low viscosity, thinner consistency) and mucus secretions, thinner consistency) and mucus secretions, lubricates the boluslubricates the bolus

Parotid: produces serous saliva which helps the Parotid: produces serous saliva which helps the bolus to be transported through the pharynxbolus to be transported through the pharynx

Salivary response stimulated by sight, smell, and Salivary response stimulated by sight, smell, and taste of food taste of food

Ch. 9 Physiology of Mastication and Deglutition. Introductory Terms Dysphagia: A disorder of...

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