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Adult Dysphagia > Lecture Two > Flashcards

Lecture Two Flashcards

Anatomy of the Swallow

1
Q

Dysphagia

A

Difficulty in Swallowing

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2
Q

Odynophagia

A

Pain with swallowing

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3
Q

Deglutition

A

Swallowing

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4
Q

Bolus

A

a small rounded mass of a substance, especially of chewed food at the moment of swallowing

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5
Q

Anatomy & Physiology of the Normal Swallow
in Adults

A
  • “Swallowing involves coordination of the sequence of activation and inhibition for more than 25 pairs of muscles in the mouth, pharynx, larynx, and esophagus.”
  • Oral cavity, oropharynx and esophagus can be thought of as a series of expanding and contracting chambers, divided by muscular sphincters.
  • Propulsion of bolus → positive pressure behind bolus & vacuum/negative
    pressure in front of bolus
  • Healthy individuals simultaneously perform a sequence of sensory and
    motoric patterns without much effort or conscious awareness.
  • Swallowing is accomplished by a complex interaction of striated and
    smooth muscle whose sensory and motor components are carried by
    multiple cranial nerves.
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6
Q

Four Phases of Deglutition

A

-Oral preparatory phase
-Oral phase
-Pharyngeal phase
-Esophageal phase

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7
Q

Oral Preparatory Phase

A
  • Primary Function: to prepare solids & liquids for a safe swallow
  • Begins when food or liquid enters the mouth
  • Involves containing, manipulating and mechanically reducing the consistency
    and volume
  • Chewing (mastication) grinds solid material into a manageable texture
  • Achieved by circular and lateral motion of the mandible and tongue
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8
Q

Oral Preparatory Phase: Facial Muscles

A

Orbicularis oris
- maintains oral competence
- (1st sphincter of swallow system

Buccinator muscle
- Muscle of cheek contracts to keep bolus
from pooling in pockets (sulci)

Both receive neural input from the facial nerve (VII)

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9
Q

Oral Preparatory Phase:
Tongue Muscles

A

4 Extrinsic Muscles
- Hyoglossus; Styloglossus; Palatoglossus
- Aid in positioning of tongue relative to the oral cavity and pharyngeal structures
- Genioglossus

4 Intrinsic Muscles
- Superior Longitudinal, Inferior Longitudinal, Vertical, Transverse
- Act primarily to alter shape and tone of tongue-along with genioglossus

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10
Q

Oral Preparatory Phase: Neural Input to Tongue (Motor)

A

Hypoglossal nerve (XII), carries motor nerve fibers that innervate both intrinsic and extrinsic tongue muscles (except for palatoglossus)

A branch of pharyngeal plexus from Vagus nerve (X) sends motor fibers to innervate palatoglossus

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11
Q

Oral Preparatory Phase: Neural Input to Tongue (Sensory)

A

Mechanoreceptors within/on surface tongue are important for determining bolus size

Sensory info from ant. 2/3 of tongue is carried back to central swallowing control center via lingual branch of Trigeminal (V)

Sensory info from post. 1/3 of tongue carried by glossopharyngeal nerve (IX)

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12
Q

Oral Preparatory Phase: Bolus Formation

A

Throughout the cyclic sequence, saliva is mixed with the material to lubricate and form a bolus

Musculature of the cheeks prevents pooling

Velum is situated anteriorly and inferiorly to
prevent premature spillage

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13
Q

Oral Preparatory Phase: Chewing

A

MUSCLES OF MASTICATION:
- Masseter closes the jaw, moves mandible up
- Temporalis moves jaw up, forward or back
- Medial Pterygoids work bilaterally to close jaw
- Lateral pterygoids open, protrudes, side to side movement
- Motor fibers controlling the contraction of these muscles are carried in branches of trigeminal nerve (V)

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14
Q

Oral Preparatory Phase: Liquids

A
  • Tongue cupped at the alveolar ridge, with lateral margins sealed at lateral alveolus
  • “Collected” bolus is ready to be transported
    posteriorly for the oral and pharyngeal phases
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15
Q

Oral Preparatory Phase: Solids

A
  • Mastication (lateral & rotary)
  • Gnashed food falls medially to be repositioned for further breakdown
  • Chemical digestion
  • Peripheral feedback to protect tongue
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16
Q

Salivation

A

Controlled by the salivatory nucleus in brainstem

Saliva serves to:
- lubricate & dilute the bolus for swallowing
- maintain oral moisture
- reduce tooth decay
- assist in digestion
- naturally neutralize stomach acid from reflux

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17
Q

Oral Prep -> Oral Phase

A

Oral Phase is next step in process

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18
Q

Oral Phase

A
  • Initiated when the bolus is propelled posteriorly towards the back of the mouth
  • Voluntary: 1 - 1.5 seconds to complete
  • Tongue presses the bolus against the hard and soft palate for initiation of a pharyngeal swallow
  • Specifically, the tip of the tongue is in contact with the lateral alveolar ridge, which results in a central furrow
  • Serves as an incline for the bolus to be propelled posteriorly into the pharynx
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19
Q

Oral Phase: Muscle Involvement

A

Elevation of palate occurs due to contraction of levator veli palatini muscle
- Receives motor innervation from Vagus (X) via pharyngeal
plexus

  • Hyoglossus posterior tongue depression (XII)
  • Styloglossus tongue up and back during swallowing
  • Palatoglossus raises BOT
  • Contraction of orbicularis oris and buccinator muscles prevent pressure from escaping forward, out of the mouth
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20
Q

Oral Phase Requirements

A
  • Labial seal
  • Lingual movement & coordination
  • Buccal musculature
  • Palatal musculature
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21
Q

Oral Phase Continued

A

Tongue tip + Dorsum → contain & ramp
Posterior tongue → more responsible for
delivering bolus to pharynx

Before (or simultaneous to) the first posterior tongue movement, respiration ceases
- Arytenoid cartilages approximate
- VFs adduct

22
Q

Respiration & the Swallow

A
  • Protection of airway is paramount
  • Respiration & Deglutition → Linked
    anatomically (mouth & pharynx) and
    neuroanatomically (medulla & brainstem)
    *** There is a functional relationship
23
Q

Swallow Apnea

A
  • Period of airflow inhibition
  • During mastication, respiratory patterns are
    modified from tidal pattern
  • Apnea does not occur until bolus is at level of valleculae
  • Small exhalation occurs just before apnea
  • When tail of bolus passes through the UES (but before the UES is fully closed, but mostly), larynx descends, respiration resume (with exhalation)
  • Exhalation + release of subglottal air pressure
  • Safety feature
  • Audible burst
24
Q

Exhalation-Swallow-Exhalation pattern

A
  • May change w/ age
  • Duration, typically 0.75-1.25 second
  • Variables: age & bolus size
  • Bigger bolus → longer apnea period
25
Q

Pharyngeal Phase

A
  • Passage of food through pharynx and into esophagus occurs
  • Phase is involuntary
    *** begins when pharyngeal swallow is triggered
  • Bolus enters pharynx
  • Hyoid bone continues anterior & superior
    movement toward edge of mandible
  • Larynx tilts under the retracting tongue (airway protection)
  • Pharyngeal constrictors (all 3) are active to
    sequentially narrow and shorten the pharynx
  • Peristalsis-like, stripping action of posterior
    pharyngeal wall
  • Aids bolus propulsion

***Upward and forward movement of hyoid
bone is important in applying traction forces on the UES to have maximum opening
- parasympathetic signals from glossopharyngeal nerve CN IX sent to brainstem, relax the UES
- UES pulled open by hyolaryngeal movement
- Bolus tail enters esophagus, UES closes & esophageal peristalsis begins

26
Q

Beginning of the Pharyngeal Phase

A
  • Sensory receptors in tongue & oropharynx are stimulated
  • Send sensory info to brainstem & cortex
  • Swallow is triggered when head of bolus passes any point between faucial arches or the point where tongue base crosses lower rim of mandible.
  • Young & middle-aged adults @ anterior faucial arches
  • Older adults (60+) at the point where tongue base crosses lower rim of mandible.
27
Q

Pharyngeal Phase: Physiological Events

A

Several simultaneous physiological events occur:
1) Velopharyngeal Port Closure
2) Tongue base movement/ Pharyngeal Wall action
3) Laryngeal closure
4) Anterior and Superior movement of the hyoid bone & larynx
5) Cricopharyngeus / Upper Esophageal Sphincter (UES) opening

Duration about 1 second

28
Q

Pharyngeal Phase: Velopharyngeal Closure

A

levator veli palatini, tensor palatini and palatopharyngeus muscles contract →

to seal the velopharyngeal port and prevent material from entering the nasopharynx and to generate pressure within the pharynx

29
Q

Pharyngeal Phase: Tongue base movement

A
  • Pressure is generated when the tongue base and pharyngeal wall contact and create a peristaltic wave to drive bolus propulsion
  • Pressure generated by tongue base and pharyngeal contractions intensifies as bolus viscosity and volume increases
30
Q

Pharyngeal Phase: Laryngeal closure

A

3 laryngeal sphincters to prevent foreign material from entering the trachea and lungs

31
Q

3 Levels of Airway protection

A
  • True Vocal Folds
  • Arytenoid Base of Epiglottis False Vocal Folds
  • Epiglottis Aryepiglottic Folds
32
Q

Pharyngeal Phase: Anterior and Superior movement of the hyoid bone & larynx

A

via the contraction of the suprahyoid musculature (the anterior belly of the digastric, mylohyoid, geniohyoid, stylohyoid, stylopharyngeus, and the thyrohyoid muscles)

33
Q

Pharyngeal Phase: Cricopharyngeal / Upper Esophageal Sphincter (UES) opening:

A
  • occurs secondary to hyolaryngeal excursion, due to anterior and superior movement of this region
  • UES is the most proximal barrier for pharyngeal and GI reflux and protects the pharynx and airway from gastric contents.
  • Synchronization of the UES relaxation with
    pharyngeal driving forces is imperative for complete transfer of the ingested bolus into the esophagus
34
Q

Pharyngeal Transit Time

A

the total duration of time for the bolus to travel from the point at which the pharyngeal swallow is activated until entry into the UES

Involuntary: .6 to 1.0 seconds to complete

35
Q

Esophageal Phase

A
  • Requires an ordered pattern of
    coordinated activities
  • Esophageal Transit Time: Time from bolus entering UES & exiting the LES; 8-20 seconds
  • Peristalsis: Top of esophagus, sequentially
    downward
36
Q

Overview of Phases of Swallowing

A
  • Oral preparation phase: Place food in mouth, manipulate/ chew food (time varies)
  • Oral phase (1-1.5 seconds): Propel bolus posteriorly
  • Pharyngeal phase (.6 to 1 second): Transit bolus vertically through pharynx
  • Esophageal phase (8-20 seconds): Transit bolus vertically through esophagus
37
Q

Neurological Control

A
  • Swallowing is dependent on both sensory and motor control
  • Afferent neurons (sensory) carry nerve impulses from sensory stimuli towards the central nervous system and brain
  • Efferent neurons (motor) carry neural impulses away from the central nervous system and towards muscles to cause movement
  • Sensory Input -> drives motor output
  • Complex oropharyngeal muscle contraction and relaxation sequence is triggered and controlled by a group of neurons within Reticular Formation of brainstem, specifically the Nucleus Tractus Solitarius (NTS) and Nucleus Ambiguus (NA).
  • These neurons are collectively referred to as the Central Pattern Generator (CPG)
38
Q

Central Pattern Generator (CPG)

A

CPGs are networks of neurons that can produce repetitive, rhythmic muscle activity in the absence of sensory feedback

39
Q

Nucleus Tractus Solitarius (NTS)

A

NTS houses sensory nuclei of:
- CN VII (Facial)
- CN IX (Glossopharyngeal)
- CN X (Vagus)
- Provide peripheral sensory feedback to CPG

  • Sensory from tongue (taste), velum, pharynx, larynx, upper GI
  • Integrates the cardiovascular system, respiration, taste, swallowing
  • Most of CN IX and CN X synapse in the NTS
40
Q

Nucleus Ambiguus (NA)

A

NA houses motor nuclei for:
- CN IX (Glossopharyngeal)
- CN X (Vagus)
- CN XII (Hypoglossal

  • Important for palatal, pharyngeal, laryngeal, esophageal muscle function
41
Q

How does the CPG Work?

A
  • Studies have shown that if you electrically stimulate these areas in the brainstem, you can elicit a swallow response
  • This means that CPGs can produce muscle activity in the absence of sensory feedback from the structures involved, making it a semi-automatic process
  • BUT that swallow will not be fully functional which is why we know we also need some cortical input to have an effective swallow

***The Swallow CPG CAN BE MODULATED
- Continuous sensory feedback from pharynx may influence the neurons of CPG, thus modulating the central program

42
Q

Areas of the Cortex potentially involved in Swallowing

A
  • Pre-central gyrus / Postcentral gyrus
  • Insular cortex
  • Anterior cingulate cortex
  • Supplementary motor area – premotor
  • Frontal operculum
  • BA 44, 45 (Broca’s!)
  • Cerebellum
  • Basal ganglia
43
Q

Swallow Response

A
  • When the swallow response is initiated, this center causes messages to be sent to glossopharyngeal, vagus, and hypoglossal nerves
  • Glossopharyngeal is considered the major nerve for the swallowing center

Six cranial nerves provide innervation for swallowing:
- CN V Trigeminal Nerve
- CN VII Facial Nerve
- CN IX Glossopharygeal Nerve
- CN X Vagus Nerve
- CN XI Spinal Accessory Nerve
- CN XII Hypoglossal Nerve

44
Q

Trigeminal Nerve (CN V)

A

Motor Component
- Innervates the muscles involved in chewing
- Innervates the tensor veli palatini muscle
- Assists the glossopharyngeal nerve in raising the larynx and pulling it forward

Sensory Component
- Carries feedback about all kinds of sensation from the anterior 2/3 of the tongue (except taste)
- Also carries sensory information from parts of face, mouth and mandible

45
Q

Facial Nerve (CN VII)

A

Motor Components
- Innervates lip muscles including orbicularis oris and zygomaticus
- Contraction during oral preparatory and oral stages prevent food from dribbling out
of the mouth
- Innervates buccinator muscles
- Must remain tense during the oral stage to prevent pocketing in sulci

Sensory Component
- carries information about taste from the anterior 2/3 of the tongue

46
Q

Glossopharyngeal Nerve (CN IX)

A

Motor Components
- innervates the 3 salivary glands in the mouth
- saliva mixes with the chewed up food to form a bolus
- Provides some innervation to the upper pharyngeal constrictor muscles, along with the Vagus (X)
- Innervates the stylopharyngeus muscle
- elevates the larynx and pulls it forward during the pharyngeal stage
- aids in the relaxation and opening of UES

Sensory components
- mediates all sensation, including taste, from posterior 1/3 of tongue
- carries sensation from the velum and the superior portion of pharynx

47
Q

Vagus Nerve (CN X)

A

Motor Components
- responsible for raising the velum as it innervates the palatoglossus and the
levator veli palatini muscles
- Innervates pharyngeal constrictor muscles (with IX)
- Innervates intrinsic musculature of the larynx
- responsible for vocal fold adduction during the swallow
- innervates the cricopharyngeus muscle
- controls the muscles involved in the esophageal stage of the swallow as well as those that control respiration

Sensory Component
- carries sensory information from the velum and posterior and inferior portions of the pharynx
- mediates sensation in the larynx

48
Q

Spinal Accessory Nerve (CN XI)

A

Motor Components
- innervates the palatopharyngeus muscle which depresses the velum and constricts the pharynx
- innervates the muscularis uvula which tenses the velum
- innervates the levator veli palatini (with CN X)

49
Q

Hypoglossal Nerve (CN XII)

A

Motor Components
- innervates all extrinsic and intrinsic tongue muscles
** It is strictly a motor nerve

50
Q

Review of Respiration and Swallowing

A
  • Breathing is always chosen over swallowing
  • Initiation of swallow during exhalation
  • Apneic period during the swallow
  • Return to exhalation
  • Patients with dysphagia, dementia, infants may initiate the swallow during the inhalation phase
51
Q

Older Adults A&P

A

Mastication patterns → steady
- Dentition
- Less dentition → more chewing required

  • With age, ossification of thyroid & cricoid cartilages
  • Cervical arthritis
  • Can be seen on MBS
  • Esophageal transit prolonged

-After 60 years, certain propharyngeal swallow physiology noted:
- Hold bolus at floor of mouth & pick it up with tongue tip as oral stage initiates
- Slightly longer oral phase → leads to a normal delay in pharyngeal trigger
- Increased in residue (oral and pharyngeal)
- Increased penetration into laryngeal vestibule (Normal!)

After 70 years
- Larynx gets lower
- Drops to 7th cervical vertebra

After 80 years, significant differences noted
- Reduced neuromuscular reserve
- Reduced maximal laryngeal and hyoid anterior movement
- No reserve to maintain laryngeal or hyoid elevation after UES opening
- With increased age → reduced UES flexibility

52
Q

The Range of Normal

A

Volume
- Bolus volume → greatest systematic change in oropharyngeal swallow
- Small bolus; Nice, sequential pattern
- Big bolus; Simultaneous oral & pharyngeal phases; Later tongue base retraction + pharyngeal wall; move toward each other and make contact when bolus tail reaches tongue base

Viscosity
- As increases → requires increased oral tongue, tongue base, pharyngeal wall activity; Valve function increase in duration

Cup Drinking
- Normally: Sequential, early airway closure, slight laryngeal pre-elevation as cup approaches; Airway closure extended across multiple swallows; Lip Closure maintained; VP closure maintained; UES opens repeatedly

Straw Drinking
- Healthy Way; Intraoral suction
- Unhealthy Way; Sucking with inhalation

Chugging:
- Some can chug without a swallow
- Pull larynx forward, opening the UES volitionally
- Hold breath to close airway
- Volitional control over process

Adult Dysphagia (9 decks)

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