Lecture 2 Flashcards
Oral structures involved in swallowing
Lips Teeth (24 deciduous, 32 permanent) Maxilla (hard palate) Velum (soft palate) - shared with oropharynx Uvula Mandible Floor of mouth Tongue (all but base) Faucial arches (anterior and posterior) Palatine tonsils Sulci - anterior & lateral Salivary glands - parotid, submandibular, sublingual
Oral muscles involved in swallowing
Tongue
Intrinsic muscles: superior longitudinal, inferior longitudinal, transverse, vertical (after shape)
Extrinsic muscles: genioglossus, hypoglossus, styloglossus, palatoglossus (protrude/retract, elevate/depress)
Roof of mouth
Palatoglossus: in anterior faucial arch;pulls velum down & forward against back of tongue
Palatopharyngeus: in posterior faucial arch; helps elevate & retract velum (VP closure)
Pharyngeal structures involved in swallowing
Pterygoid plates on sphenoid bone (nasopharynx) Velum (oropharynx) Tongue base Mandible Hyoid bone Pharynx (pharyngeal walls) Epiglottis Thyroid cartilage Cricoid cartilage Vallecula (plural is valleculae) Pyriform sinuses
Pharyngeal muscles involved in swallowing
Suprahyoids/Submentals
- Mylohyoids
- Geniohyoids
- Digastrics (anterior belly)
Infrahyoid - Thyrohyoid
Constrictors
- Superior, middle, interior > posterior & lateral walls
Cricopharyngeus (CP)
- Inferior constrictor fibers attached to cricoid lamina; prevents air from entering esophagus, reduces backflow
- These muscle are tonic at rest aka they rest closed
What muscles help elevate and protract the hyoid bone?
Mylohyoid, geniohyoid, and digastric muscles
What does the thyrohyoid do?
Allow larynx to follow hyoid bone less otherwise manipulated
Laryngeal structures involved in swallowing
Hyoid bone
Epiglottis
Valleculae - pockets above/to side of epiglottis, can fill up with premature spillage
Laryngeal vestibule - From the epiglottis down to the VFs
Aryepiglottic folds > lateral vestibule walls
Thyroid cartilage
Arytenoid cartilage
False vocal folds
True vocal folds
Ventricles (lateral)
Laryngeal muscles involved in swallowing
PCA (posterior cricoarytenoid)- attaches cricoid lamina to arytenoid; abducts arytenoids/vocal folds for respiration at end of swallow
LCA (lateral cricoarytenoid) - attaches cricoid cartilage to arytenoid; adducts arytenoids/vocal folds
Interarytenoid - attaches 2 arytenoids; adducts arytenoids/ vocal folds
TA (thyroarytenoid) - attached thyroid cartilage to arytenoid; tilts arytenoids anteriorly during swallow to assist with airway closure **makes up VFs
Laryngeal strap muscles
- Thyrohyoid: attaches thyroid cartilage to hyoid bone; elevates & lowers larynx
- Sternothyroid: attaches sternum to thyroid cartilage; suspends larynx & trachea in neck
- Sternohyoid: Attaches sternum to hyoid; lowers & stabilizes hyoid
Esophageal structures involved in swallowing
UES (Upper esophageal sphincter) - aka CP (cricopharyngeus) - aka PE segment (pharyngoesophageal sphincter) Esophagus (about 25 cm) LES (lower esophageal sphincter)
Esophageal muscles involved in swallowing
UES - keeps air out of esophagus, keeps contents swallowed from coming back up
LES - keeps contents in stomach
2 layers of muscle in esophagus
- Inner circular
- Outer longitudinal
^^ both are striated/smooth muscle
What occurs in the oral stage of swallowing?
- Time of the stage varies with consistency
- Labial muscle, lingual movement, sensory receptors, buccal muscle, nose breathing
- Mastication: rotary lateral movement of jaw & tongue
- Bolus formation: tongue mixes bolus with saliva
- Bolus transport: tongue’s posterior movement of bolus from the oral cavity to the pharynx
Increased viscosity = decreased volume = increased pressure = increase muscle activity
Could lead to -> multiple swallows
Tipper or dipper?
Normal/healthy swallowers have tongues that are “tippers”
Abnormal swallowers are “dippers”
What occurs in the pharyngeal stage of swallowing?
- Time of the stage is about 1 second
- Velum elevates & retracts for VP closure, bolus transport with tongue base retraction & pharyngeal wall contraction
- Epiglottis inverts, hydaryngeal elevation & protraction
- Closure of larynx
- CP opening
- Transport by pharyngeal constrictors
- CP closure, larynx rests
What are the two layers of protection in swallowing?
- Epiglottis
2. True vocal folds
What triggers the pharyngeal swallow in healthy swallowers? In the elderly? In neurogenic populations?
Healthy - When head of bolus hits anterior faucial pillars
Elderly - When head of bolus reaches middle tongue base
Neurogenic - When head of bolus reaches middle tongue base or when it falls into the pyriforms
What occurs in the esophageal stage of swallowing?
- Time of the stage is about 8-20 seconds long -> Transit time is measured from UES through LES
- Bolus flow through the esophagus via peristaltic contractions of striated and smooth muscle along the esophageal wall
- Relaxation of LES allows bolus to flow into stomach
Normal swallowing A&;P variations in young
- Higher hyoid & larynx (better protection), less elevation
- Lower velum, shorter pharynx
- Uvula in epiglottis, pocketing valleculae
- Pharyngeal swallow is triggered at anterior faucial arch (bolus flow uninterrupted, no pause)
Children aren’t as vulnerable to aspiration
Normal swallowing A&P variations in older
- Ossification of cartilages & hyoid bone
- Pharyngeal swallow triggered when bolus head reaches middle of tongue base
- 70+ have a lower larynx
- Arthritis in C vertebrae impinge on pharyngeal wall
- “Dippers”
- Delay, residue, penetration
- Reduced hyolaryngeal excursion, plateaus at CP opening
- Reduced CP opening flexibility
Normal swallowing A&P variations in neurologic
- Pharyngeal swallow triggered when bolus head reaches middle of tongue base or when falls into pyriforms
Cranial nerves of swallowing
Sensory/Afferent
Trigeminal V - Sensation anterior 2/3 of tongue
Facial VII - Taste anterior 2/3 of tongue
Hypoglossal XII - Sensation, mucous membranes of pharynx, palate, posterior tongue and tonsils
Vagus X - Mucous membrane of pharynx, larynx, bronchi, lungs, esophagus, stomach
Glossopharyngeal IX - Taste & sensation posterior 1/3 of tongue
Cranial nerves of swallowing
** Motor/efferent**
Trigeminal V - Mastication
Facial VII - Lips, face, salivary glands
Hypoglossal XII - Tongue
Glossopharyngeal IX - pharynx, gag reflex
Vagus X - Trachea, larynx, pharynx, cough reflex
Accessory XI - Uvula, palate, pharyngeal constrictors
What part of the brain controls swallowing?
The brain stem
Possibly cortex??
Central Pattern Generator
Apneic period of swallowing
- During pharyngeal stage
- Lasts about one second
- Increases as volume increases
- Mostly during exhalation (most people swallow at exhalation)
