Anatomy and Physiology of Normal Deglutition Anatomic Structures Oral Pharynx Larynx Esophagus

ORAL Lips anteriorly Teeth (24 Decidous, 32 Permenant) Hard Palate Soft Palate Uvula Mandible Floor of Mouth Tongue Faucial Arches Know this

Natural Cavities/Spaces Sulci Natural Cavities/Spaces Anterior Sulcus Lateral Sulcus Why would we be concerned about the sulci? -Residue

Musculature of the Floor of Mouth Mylohyoid Geniohyoid Anterior Belly of Digastric All of which attach to the body of the madible anteriorly and the body of the hyoid bone posteriorly

Hyoid Forms foundation of the tongue Larynx is supended from the Hyoid Bone by the Thyrohyoid Ligament and Thyrohyoid muscle If the Hyoid elevates and moves forward, the larynx will move upward and forward unless it is stabilized by other muscles If one of these components are weak-the rest will become weak The hyoid is the anchor

Pharyngeal (Tongue base) Oral Tip Blade Front Center Back Ends at Circumvallate Papillae Active Under Cortical/Voluntary Neural control Pharyngeal (Tongue base) Begins at the Circumvallate Papillae, ends at the Hyoid bone Active during pharyngeal swallow Involuntary neural control – brainstem Can be placed under some degree of voluntary control Brainstem stroke: may not have a swallow Stroke in left frontal cortex- Oral apraxia, flaccid dysarthria

4 back 5 tongue base 6 extends from CVP to tip of uvula to hyoid

Velopharyngeal closure muscle pulls Oral Cavity Hard palate/Maxilla Velum/soft palate Uvula Velopharyngeal closure muscle pulls Palatopharyngeus Levator palatal muscle Superior Pharyngeal constrictor

Salivary Glands Viscid – mucus like Serous – watery Maintain oral moisture Reduce tooth decay Assist in digestion Neutralize stomach acid Water slide without water= swallowing without saliva

Form posterior and lateral pharyngeal walls Pharyngeal Cavity 3 Pharyngeal constrictors Superior Medial Inferior Form posterior and lateral pharyngeal walls

Form the anterior wall of the pharynx Pharyngeal cavity Run laterally to attach to bony and soft tissue structures located anteriorly: pterygoid plates, soft palate, Base Of Tongue, mandible, hyoid bone, thyroid and cricoid cartilages Form the anterior wall of the pharynx Inferior fibers of the superior constrictor attach to tongue base/glossopharyngeus muscle. Tongue Base Retraction and Anterior bulging of the post pharyngeal wall at tongue base. Tongue base has to make contact with the posterior pharyngeal wall—forces food down—creates a negative pressure

Pyriform Sinuses Spaces formed between fibers of inferior constrictor and sides of thyroid cartilage Spaces end at cricopharyngeal muscle Things enter the airway because they’re trying to find the path of least resistance

Cricopharyngeal muscle Attach to cricoid lamina Cricoid lamina/cricopharyngeus forms valve into esophagus called the cricopharyngeal region CP Upper Esophageal Sphincter Pharyngeal Esophageal segment These are the AREA not CP itself Tonic (tone) when awake, loses tonic with sleep Prevents air into esophagus with respiration Reduce material backflow into pharynx Sphincter 2-4 cm zone of elevated pressure – greatest pressure immediately prior to swallow and during inspiration

Esophagus Collapsed muscular tube 23-25 cm long with sphincter at each end UES/LES Pharynx open vs. esophagus closed Sits behind trachea – TE wall (party wall) LES (esophagus and stomach) keep food and secretions in 2 layers of muscle: inner circular and outer longitudinal Esophagus is always closed unless there is food in it Peristalsis- process of pulling—what is moving things down UES/LES work in unison—if one isnt up to speed that affects the other

Larynx Base of tongue, pharynx opens into larynx Topmost epiglottis Attached into hyoid bone by a ligament Base attached to thyroid notch Epiglottis inversion- pressure from tongue base retraction and muscles(head/neck cancer patients lack this)

Larynx Wedge-shaped space is the Valleculae Open into larynx is Laryngeal Vestibule, which ends at superior surface of false folds Aryepiglottic folds form lateral walls Arytenoids tilt anteriorly during swallowing, thought to be from pull of the thyroarytenoid muscle fibers. Tilt contributes to closure of airway True cords form last level of airway protection Penetration- goes into the laryngeal vestibule

Larynx 3 levels of sphincter in the larynx Epiglottis and aryepiglottic folds Arytenoids False Cords Above the true chords is your laryngeal vestibule

Larynx Larynx elevates Pull anteriorly and lowers for various activities Hyoid bone serves as foundation for the tongue When one structure moves, it often pulls on and moves attached structures Elevation is up Excursion is the tilt

https://www.youtube.com/watch?v=YoDh_gHDvkk https://www.youtube.com/watch?v=hdcTmpvDO0I

Physiology Oral prep: food manipulated/masticated Oral phase of swallow: tongue propels food post till pharyngeal swallow triggered Pharyngeal Phase: bolus moved through pharynx Esophageal phase: cervical – thoracic to stomach *duration and characteristics depend on volume and type *580 swallows per day *respiration and swallow are reciprocal – halts w/ pharyngeal phase in all ages

1. Oral Prep Needs sensory recognition Movement varies w/ viscosity Requires open nasal airway and nasal breathing Tippers and Dippers Tippers – food held midline w/ tip elevated and contact w/ alveolar ridge Dippers – 20%, food held floor of mouth in front of the tongue Tongue thrust – tongue moves anteriorly w/ the bolus pushing food from the mouth. Seen w/ adults with frontal lobe damage and children w/ CP.

Oral Prep Soft palate is pulled down and forward, sealing off the oral cavity from pharynx Mastication involves a rotary lateral movement of mandible and tongue. Tongue mixes food w/ saliva w/ peripheral feedback to position bolus on teeth and prevent injury to tongue Tension in buccal musculature closer of lateral sulcus After chewing, tongue pulls food into semi-cohesive bolus before oral stage of swallow initiated

Oral Prep Active chewing, soft palate not pulled down, thus premature spillage common, not normal during hold phase of liquid/pudding Volume of bolus swallowed varies w/ viscosity; this downsizing w/ viscosity allows easier passage through pharynx and UES. Larger volumes, the tongue will subdivide Larynx and pharynx are at rest during oral prep phase Great deal of sensory info is processed from sensory receptors throughout the oral cavity

2. Oral Phase Initiated when tongue begins post movement of bolus Sides and tip of tongue anchor against the alvelor ridge. Central groove is formed and acts as a chute Viscosity thickens, pressure of the oral tongue against palate increases – negative pressure of tension of buccal musculature 1-1.5 seconds Needs labial seal, intact lingual movement, intact buccal musculature, normal palatal muscle, and ability to breath through nose

Bolus propulsion

3. Triggering of Pharyngeal Swallow As the tongue movement propels the bolus post, sensory receptors in the oropharynx and tongue are stimulated, sending sensory info to cortex and brainstem Bolus head passes faucial arches and tongue base crosses the lower rim of the mandible, oral stage is terminated and pharyngeal swallow is triggered If pharyngeal stage is not triggered by that time, delayed Humans cannot swallow unless there is something in their mouth Once triggers pharyngeal swallow—all involuntary

Triggering Pharyngeal Swallow Sensory portion of pharyngeal swallow cranial IX, X, XI. Impulses travel to the swallow center in brainstem. Motor IX and X Cortical recognition of bolus critical to initiation of oral phase

4. Pharyngeal Swallow 1. Velopharyngeal closure: elevation and retraction of the velum and complete closure of the velopharyngeal portion to prevent material from entering nasal cavity. Enables build up of pressure in the pharynx.

Pharyngeal Swallow 2. Elevation and anterior movement of the hyoid and larynx: Elevate and move anteriorly by the pull of the floor of mouth muscles (anterior belly of digastric, myolohyoid, geniohyoid, laryngeal elevator-thyrohyoid). Average elevation 2 cm. Elevation contributes to closure of the airway, forward movement contributes to opening of the UES. ELEVATES AND MOVES ANTERIORLY **********KNOW KNOW KNOW***************

Pharyngeal Swallow 3. Closure of the Larynx: all 3 sphincters – true folds, laryngeal entrance (false folds, anterior tilt arytenoids, thickening of epiglottic base) and epiglottis. Airway closed 1/3-2/3 second and 5 seconds w/ sequential cup drinking. TVC close when larynx has elevated approx 50% of max elevation.

Pharyngeal Swallow 4. Cricopharyngeal opening: tension in the cricopharyngeal muscle portion of the sphincter is released. Laryngeal anterior-superior motion opens the sphincter, sphincter is yanked open by the motion of the larynx resulting from the upward and forward pull of the floor of mouth muscles. Pressure w/in bolus widens the opening. Once passed, larynx lowers and cricopharyngeal muscle returns to level of contraction. Chords= last effort for airway protection

Pharyngeal Swallow 5. Tongue base and pharyngeal wall action: when bolus reaches tongue base level, tongue base and pharyngeal walls should make complete contact during the swallow. Move towards each other, pressure builds. Pharyngeal wall contracts (causes more pressure) and continues down pharynx to UES.

Peristalsis Progressive contraction down a muscular tube **Pressure generated by TBR and pharyngeal wall constriction increases w/ bolus viscosity. Pressure applied to the tail of the bolus.

Movement Velopharyngeal closure and hyolaryngeal excursion occurs simultaneously Open UES and airway closure Pressure on bolus 1. oral tongue pushes tail 2. tongue base reaches pharyngeal wall and apply pressure to bolus.

Always Remember This Pharyngeal swallow must trigger for physiological activities (Velar, pharyngeal, tongue base, laryngeal) to occur. These activities occur ONLY as a result of triggering pharyngeal swallow! There is no way to voluntary initiate or modify pharyngeal contraction!

Movement Pharyngeal transit time – time bolus to move from point pharyngeal swallow is triggered through the cricopharyngeal juncture into esophagus. 1 second or less. Divides at the valleculae w/ ½ flowing down each side of pharynx through pyriform sinuses Epiglottis directs food around the airway Joins again at UES

Esophageal Phase Time from UES to LES/stomach varies 8-20 seconds. Bolus pulled through w/ peristaltic wave

Mechanism as a Set of Tubes & Valves Oral cavity – horizontal Pharynx – verticle UES – musculoskeletal valve (cricopharyngeal muscle & cricoid cartilage) LES – muscular sphincter. Keep food/stomach acid in stomach

Changes with Age Infant: tongue fills the oral cavity. Hyoid bone and larynx are up, velum hangs lower, uvula rests inside epiglottis and forms pocket in valleculae. Greatest elongation of the pharynx and downward displacement of larynx occurs during puberty **Suction

Infant Swallow begins in the fetus. Sucking nipple, infant repeatedly pumps the tongue expressing milk. Normal infants 2-7 pumps. Bolus of adequate size has been formed, triggers pharyngeal swallow. 1ml liquid produces oral then pharyngeal swallow (similar to adult). Bite achieved approx 7 months Chewing 10-12 months Normal adult pattern 3-4 years Infants don’t have oral swallow—just pharyngeal

Older Adult Number of chewing strokes related to age and dental status. Increased strokes w/ poor dentition or dentures. Physiological changes occur 70+. Ossification of thyroid and cricoid cartilages and hyoid bone, appear more prominent. Larynx may begin to lower. Cervical arthritis, impinge on pharyngeal wall decreases flexibility, decrease strength of pharyngeal contraction. Patients with dentures arent getting additional sensory output—actually swallow better without them Posture, posture, posture

Age and Swallowing Dipper longer oral stage More pharyngeal residue- everything is becoming weak and flaccid Increased penetration w/out aspiration Longer esophageal transit Muscles becoming flaccid*

Age and Swallowing Decreased max laryngeal and hyoid anterior and vertical movement indicating reduced neuromuscular reserve (difference between necessary movement and actual motion)

Age and Swallowing Decreased flexibility cricopharyngeal opening – less change as volume increased, exacerbates w/ weakness Taste – intensity of taste & smell are reduced

Coordination of respiration & swallowing Apneic period – fraction of second. Corresponds w/ closure of airway during pharyngeal stage. Duration increases bolus volumes Airway opens w/ oral prep, oral, and esophageal stages Interrupting exhalation and returning to exhalation after the swallow Slight airflow through the larynx and pharynx after the swallow May clear any residue from around the airway entrance Dysphagia patients may more often interrupt inhalation to swallow

Variations in normal swallowing Volume effects – bolus volume creates greatest systematic changes in oropharyngeal swallow. Small volume – each phase, whereas large (10-20ml) simultaneous oral & pharyngeal activity Increased viscosity – increased pressure. Valve functions all increase slightly in duration Cup drinking – early airway closure, duration 5-10 seconds Straw drinking – suction ‘chug-a-lug’ – pull larynx forward & hold breath Pharyngeal swallow w/ no oral swallow

Components of All Swallows Components that must be present Oral propulsion bolus into pharynx Airway closure UES opening Tongue base – pharyngeal wall propulsion to carry the bolus through the pharynx and into the esophagus Variations on normal swallow generally involve changing the timing of these elements, but all must be present and normal for bolus to clear safely and efficiently! ****************