Degluttition W5 Flashcards
swallowing and slp
slts diagnose and treat adults and children with swallowing impairment
same peripheral nerves supply the muscles involved in speech and swallowing
CNS controls for speech and swallowing quite different
what is mastication and degluttion?
mastication is the process of food preparation in the mouth, chewing
degluttion is the process of swallowing. ingesting food via the mouth, through the pahrynx and into the stomach
whats involved in mastication and deglutition?
facial, lingual, velar, pharyngeal, laryngeal muscles and respiratory coordination
anatomy of swallowing
oral cavity - lips, tongue, teeth, hard palate, soft palate, mandible, the inside lining of the cheeks (buccal cavity)
nasal cavity - velopharyngeal closure
pahrynx - epiglottis, vallecular, pyriform sinus
larynx - hyoid bone, laryngeal vestibule term typically used to include ventricle and vestibule i.e. above vocal folds, vocal folds
what is the esophagus?
muscular mucous lines tube beginning with the cricopharyngeal sphincter and extending down through the diaphragm to the stomach
UES and LES
what are salivary glands
parotid - largest salivary gland 20-25%, lies over tmj, cn ix
sublingual - smallest salivary gland 5-10%, in floor of mouth, cn vii
submandibular - provides majority of saliva 60-65%, medial to mandible in floor of mouth, cn vii
digeestive tract
neurophysiological compexity of mastication and deglutition
very complex task with precise use of 55 pairs of smooth and skeletal muscles supplied by 5 cn controlled by many brain regions
unconscious swallowing takes between 800-1200ms
relatively poor design breathing and swallowing
how do we achieve complex behaviour?
neonates use reflexes for first couple of months
rooting reflex - turn towards anything that strokes their cheek or mouth and search for that object
sucking reflex - protrusion of the tongue repeated forward pumping of the tongue and mandible together to elicit milk
infant vs adult anatomy
soft palate and epiglottis approximate in infants but not adults
infants’ tongue occupies larger space in oral cavity compared to adults
position of larynx more directly under tongue in infants than in adults - decends over first 4 years
why cant we breathe and swallow at same time
what happens beyond reflexes?
dentition ~8 months
helps with retraction of the tongue for mature swallowing
supports mastication muscle development
important for oral structure development - though counteracting the tongue pressue required to transfer food (i.e. holds mandible in place)
hard palate > dental arches
cranial nerves in swallowing
trigeminal v
facial vii
glossopharyngeal ix
vagus x
hypoglossal xii
pharyngeal plexus ix x
ansa cervicalis c1 and c2
phases of swallowing
3 or 4 phases
oral, pharyngeal, esophageal
pre-oral phase
oral phase divided into two, prepatory and transit
oral prepatory phase
mastication
mostly volitional
refers to the processing of the bolus to render it swallowable
involves bolus manipulation, bolus containment - glossopalatal seal
muscles and nerves of motor events of oral-prepatory phase
mandibular muscles - trigeminal nerve - jaw open, jaw lateralisation, bite, stabilise floor of mouth
facial muscles - facial nerve - contains bolus and directs between teeth
intinsic and extrinsic tongue muscles - hypoglossal nerve - bolus manipulation
palatoglossus muscle - pharyngeal plexus - glossopalatal seal
salivary glands - parotid (cn ix), submandibular (cn vii), sublingual (cn vii)
sensory nerves of oral-prepatory phase
tongue - anterior 2/3 sensory cn v, taste cn vii
posterior 1/3 sensory and taste cn ix
oral cavity - cn v and vii
oral phase
propelling of food from the oral cavity into the oropharynx - drop, push
sometimes called oral-transit phase or oral propulsive phase - bolus transportaiton anterior to posterior
typically lasts less than 1 second
muscles and nerves of motor events of oral phase
palatoglossus - glossopalatal seal, pharyngeal plexus
extrinsic and intrinsic tongue muscles - drop and puch extrinsic, squeeze bolus from oral cavity intrinsic, hypoglossal nerve
sensory nerves of oral phase
3 types of input to the central pattern generator
cognitive cortical processing of the food you are ingesting
senspry perception of the bolus characteristics
input from deep muscle receptors in the tongue during drop push
converge on the cpg and elicit the patterned pharyngeal swallow response
pharyngeal phase
basic pattern is under involuntary control but may be modified with volition
rapid sequence of overlapping events including:
- velopharyngeal closure, the soft palate elevated to seal off the nasal cavity. this prevents nasal regurgitation of food and fluid - no airflow for respiration
- levator tensor palatini, superior pahryngeal contrictor, musculus uvulae
- pharyngeal plexus - hyolaryngeal excursion, the hyoid bone and larynx move upward and forward
- effect is two fold changes the configuration os structures to assist laryngeal closure, pulls open cricopharyngeus which relaxes during pharyngeal phase
- abd and mylohyoid v trigem
- geniohyoid and thyrohyoid ansa cervicalis - ues opening, tonic contraction must be terminated to allow passageway of the bolus through the esophagus, vagus and pharyngeal plexus
- pressures on the descending bolus, the tongue, pharyngeal contraction and shortening (Hypoglossal, glossopharyngeal and pharyngeal plexus ix x)
- laryngeal closure, vocal folds move to midline, false vocal folds move to the midline, epiglottis folds over laryngeal aditus, the arytenoid cartilages fold forward to make contact with epiglottis
- trigemnial and ansa cervicalis (hyolaryngeal excursion for epiglottic deflection)
- vagus nerve (instrinsic laryngeal muscles)
sensory nerves of pahryngeal phase
pharynx - pharyngeal plex ix x
larynx and trachea - x, cough reflex
esophageal phase
under involuntary neuromuscular control
food/liquid transportation via a peristaltic wave
normal esophageal transport times 10-20sec
the lower esophageal sphincter relaxes and allows propulsion of the bolus into the stomach
mostly smooth muscle - peristalsis, vagus nerve
issue with pressure systems
components of swallowing do not act alone, deficits in oral phase will have effects on pharyngeal swallow regardless of specific pharyngeal deficits
four valve system
perlman and christensen 1997
swallowing is a single pressure driven event
base of tongue pushes into pharynx; large pressure differential between pharynx and esophagus
leak in the system (ues opening) creates substantial force to pull the bolus into esophagus in order to equalise pressure (fluid mechanics)
dysphagia
disordered swallowing
aspiration
entry of material below the level of the vocal folds
approx 50% of dysphagic patients aspriate
one of the major causes of bounce back admissions to hospital
a leading cause of death in elderly
