Exam #1 Flashcards
Describe the primary functions of swallowing.
- Supportive function- carrying food from the mouth to the stomach
- Protective function- protecting the respiratory system
- *necessary because in the adult human, the upper respiratory and digestive paths are crossed. Crossroads is called the “upper aerodigestive tract”
What are the four phases of the normal swallow?
- Oral preparatory
- Oral transport
- Pharyngeal
- Esophageal
Describe Oral preparatory- Phase 1
Function= Ingested material brought into the oral cavity and contained there
a. Structure= lips involved in grasping, sucking, and forming anterior oral seal; teeth and cheeks are also involved
b. Important to prevent food from spilling out
- Oral preparatory- Phase 2
Function: bolus formation
a. Structure= jaw moves in a “rotary lateral” pattern in mastication
b. tongue positions material between occlusal surfaces of teeth
c. buccal tone prevents spillage of bolus into lateral sulci (cheeks)
d. saliva has several functions: chemical breakdown of ingested material, lubrication of material, promotes oral hygiene
- Oral preparatory- Phase 3
Function= bolus containment
Structure= bolus is contained between tongue and hard palate
b. tongue tip contacts alveolar ridge to contain bolus anteriorly
c. superior tongue surface contains bolus inferiorly
d. lateral tongue margins contact maxillary teeth to contain bolus laterally
e. posterior tongue contacts soft palate to contain bolus posteriorly, forming the retro-oral seal
f. Containment Helps prevent residue in lateral sulci/under the tongue
a. Retro-oral seal prevents food from entering the nose or the lungs
Oral transport- phase 1
Function= bolus is transported posteriorly by the tongue
Structure= bolus is squeezed posteriorly between superior surface of tongue and hard palate by tongue “stripping wave” action
- Oral Transport- phase 2
Function= tongue loading
a. Structure= soft palate elevates and posterior tongue lowers, breaking retro-oral seal
b. superior tongue surface forms a central groove
c. tongue dorsum moves inferiorly and anteriorly, loading the bolus on its surface
i. Bolus sits in central groove to move backwards
Oral Transport- Phase 3
Function= pharyngeal stage of swallow is triggered
Structure= bolus stimulates sensory receptors lining anterior faucial pillars, tongue base, and posterior pharyngeal wall
- Pharyngeal- Phase 1
Function= Formation of the VP seal
Structure= soft palate (velum) contacts posterior pharyngeal wall
- Pharyngeal- Phase 2
Function= Tongue propels bolus into pharynx
Structure= mandible is stabilized
b. posterior tongue makes a piston-like motion that drives the bolus through the pharynx
- Pharyngeal- Phase 3
Function= laryngeal closure
Structure= larynx closes in an inferior to superior direction
b. true vocal fold closure
c. false vocal fold closure
d. arytenoid cartilages to epiglottic base
e. deflection of the epiglottis
f. **important safety parts
Pharyngeal- Phase 4
Function= hyolaryngeal elevation/excursion
Structure= hyoid elevates and moves anteriorly, pulling thyroid cartilage with it
b. once hyoid reaches maximal elevation, thyroid cartilage continues to elevate due to contraction of thyrohyoid muscle
Pharyngeal- Phase 5
Function= epiglottic deflection; (a) allows bolus to empty out of valleculae, (b) directs bolus laterally toward pyriform sinuses, away from laryngeal vestibule
Structure= epiglottis deflects to horizontal
b. mechanical forces of laryngeal elevation
c. epiglottis deflects below horizontal
d. active muscle forces (aryepiglotticus & thyroepiglotticus m.)
e. traction from anterior movement of hyoid (lateral hyoepiglottic ligaments)
- Pharyngeal- Phase 6
Function: opening of Upper Esophageal Sphincter (UES) allows entry of bolus into
esophagus
Structure= UES is comprised principally of the cricopharyngeus muscle
b. during swallowing, UES opens due to:
-relaxation of cricopharyngeus
-traction by anterior/superior movement of hyo-laryngeal complex
-outward pressure exerted by bolus itself (intrabolus pressure)
Pharyngeal- Phase 7
Function= bolus is cleared from the pharynx
Structure= bolus clearance:
i. propagated contraction of pharyngeal constrictors (peristalsis)
ii. shortening of pharynx
Esophageal Phase
Function= bolus transport from pharynx to stomach
Structure= primary peristalsis - progression of a peristaltic contraction along the esophagus in coordination with relaxation of UES and LES
b. secondary peristalsis - peristalsis initiated by intraesophageal distention (e.g., material from a previous swallow, gastric reflux)
Describe the process of coughing
-reflex involving afferent inputs, and forceful expulsion of air from lungs
-rapidly accelerating expiratory airflow sweeps tracheal surface
- List the four main components of the neural control of swallowing.
- Afferent input- sensory
- Medullary swallow centre- brainstem bilateral swallowing control
- Efferent output- motor nuclei, CN innervation to muscles
- Descending cortical and subcortical inputs
Name the primary brainstem nuclei involved in the CPG for swallowing.
- Dorsal swallowing group (programming component)
* * nucleus tractus solitarius (NTS) and adjacent reticular formation (RF) - Ventral swallowing group (motor component)
* * nucleus ambiguous (NA) (important nucleus for motor execution) and adjacent RF
Describe lateralization for swallowing
o Dominant in left hemisphere most prevalent
o Damage to left hemisphere increases chances of dysphagia
o For right hemisphere dominance, the dominance is stronger
Define dysphagia.
- Difficulty moving ingested material from mouth to stomach.
o Cause – malnutrition, dehydrations, AP
o Symptom – COPD, HNC, developmental disability
o Side effect – chemo, pharmacological intervention, psychological condition, breathing tube
Identify the signs of dysphagia.
- difficulty chewing food
- difficulty controlling food in oral cavity
- difficulty initiating a swallow
- coughing when swallowing food
- food sticking in throat
- reflux from esophagus or stomach
Contrast penetration and aspiration.
- Penetration- entry of foreign material into airway to the level of the true vocal folds
- Aspiration- entry of foreign material into airway beyond level of the true vocal folds (tracheal aspiration)