Ch. 9 Physiology of Mastication and Deglutition

1. Ch. 9Physiology of Mastication and Deglutition

2. Introductory Terms • Dysphagia: A disorder of swallowing • Bolus: ball of food or liquid to be swallowed • Mastication: the process of preparing food for swallowing • Moving food onto the grinding surfaces of the teeth • Chewing • mixing it with saliva in preparation for swallowing • Deglutition: the process of swallowing • Both the two above concepts require integration of lingual, velar, pharyngeal, facial muscle movement, laryngeal adjustments, respiratory control

3. Introductory Terms • Perioral region: around the mouth • Rooting Reflex: reflexive response of infant to tactile stimulation of the cheek or lips, infant turns toward stimulus, opens mouth • Sucking Reflex: tongue protrusion and retraction in preparation for receipt of liquid; stimulated by contact to the upper lip • Esophageal Reflux: esophageal regurgitation into the hypopharynx • Nasal regurgitation: loss of food or liquid through the nose • Peristaltic: Wavelike

4. Introductory Terms • Oral Transit Time: time required to move the bolus to the point of initiation of the pharyngeal stage of swallowing • Pharyngeal Transit Time: time required to move the bolus from the beginning of pharyngeal swallow to the time the bolus enters the esophagus

5. Organizational Patterns • Oral Preparatory Stage • Stage in which food is prepared for swallow • Oral Stage • Bolus transmitted to pharynx • Pharyngeal Stage • Bolus transmitted to the esophagus • Numerous physiological responses • Esophageal Stage • Food is transported from the upper esophageal region to the stomach

6. Deficit Patterns • Oral Preparatory Stage • Neuromuscular deficits • Loss of sensation and awareness • Weak buccal musculature • Weak muscles of mastication may cause inadequately chewed food • Weak lingual muscles may cause poor mixture of saliva with food, inadequate bolus production, difficulty compressing bolus onto hard palate • Weak soft palate muscles may cause the velum to not be fully depressed, tongue not adequately elevated in back, permitting food to escape into the pharynx prior to initiation of pharyngeal reflexes • Food entering pharynx prior to a reflexive response may reach the open airway and produce an aspiration pneumonia

7. Deficit Patterns • Oral Stage • Sensory and Motor dysfunction • Weakened movements cause reduced oral transit time, food may remain on tongue and hard palate following transit • Epiglottis fail to invert over laryngeal opening, limited elevation of the hyoid, may be increased pooling of food or liquid in the valleculae • Difficulty initiating a reflexive swallow may be due to a sensory deficit

8. Deficit Patterns • Pharyngeal Stage • Sensory and Motor Dysfunction • Slow velar elevation may result in nasal regurgitation • Reduced sensation of fauces, posterior tongue, pharyngeal wall, soft palate may cause elevated threshold for trigger of swallowing reflex • Reduced function of pharyngeal constrictors may result in slowed pharyngeal transit time of bolus and individual may reinitiate respiration • Weakened pharyngeal function may result in residue left in the valleculae • Failure of the hyoid and thyroid to elevate may result in loss of airway protection, food may fall into larynx and be aspirated on breathing

9. Deficit Patterns • Esophageal Stage • GERD: acids from the stomach flow to the esophagus and pharynx, may be UES or LES problem or both • Hiatal Hernia: LES may malfunction allowing reflux into esophagus • Congenital Malformation: stenosis, see figure 9-4

10. Neurophysiology • Gustation • Taste mediated by 3 cranial nerves • V!! mediates sense of taste from anterior 2/3 of the tongue, sweet and sour sensations, and of palate. Sides transmit salt and sour. • IX mediates sense of taste, primarily of bitterness from posterior 1/3 of tongue. Sides transmit salt and sour • X mediates sense of taste from epiglottis and esophagus • Umami: taste receptor which processes monosodium glutamate.

11. Neurophysiology • Gustation • Tastes, bitter and sour may typify poison and elicit a protective response • Gagging • Coughing • Apnea • Salivation (encapsulates the material and protects the oral cavity

12. Neurophysiology • Gustation • Taste can elicit motor responses that may or may not be under volitional control • Gag response • Elevation of the larynx • Clamping of the vocal folds • Elevation of the velum • Protrusion of the tongue

13. Neurophysiology • Gustation • Taste can elicit motor responses that may or may not be under volitional control • Coughing • Tightly closing VF and supraglottic structures • Compressing of abdomen and thorax • Forcefully blowing VF apart

14. Neurophysiology • Olfaction • Olfactory chemoreceptors in nasal mucus membrane • Sense of smell transmitted to olfactory bulb in cranial space

15. Neurophysiology • Tactile Sense • In face and oral cavity, primarily mediated by V, but IX and X are associated

16. Neurophysiology • Thermal Receptors • In face and oral cavity, primarily mediated by V, but IX and X are associated • Same as pain sensors, bare nerve endings • Differentiate warm, hot, cool, cold: receptors are tuned to particular temperatures

17. Neurophysiology • Muscle stretch and Tension sense • In face and oral cavity, primarily mediated by V, but IX and X are associated