Degluttition W5

Question 1

swallowing and slp

Answer 1

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

Question 2

what is mastication and degluttion?

Answer 2

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

Question 3

whats involved in mastication and deglutition?

Answer 3

facial, lingual, velar, pharyngeal, laryngeal muscles and respiratory coordination

Question 4

anatomy of swallowing

Answer 4

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

Question 5

what is the esophagus?

Answer 5

muscular mucous lines tube beginning with the cricopharyngeal sphincter and extending down through the diaphragm to the stomach

UES and LES

Question 6

what are salivary glands

Answer 6

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

Question 7

digeestive tract

Answer 7

Question 8

neurophysiological compexity of mastication and deglutition

Answer 8

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

Question 9

how do we achieve complex behaviour?

Answer 9

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

Question 10

infant vs adult anatomy

Answer 10

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

Question 11

why cant we breathe and swallow at same time

Answer 11

Question 12

what happens beyond reflexes?

Answer 12

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

Question 13

cranial nerves in swallowing

Answer 13

trigeminal v

facial vii

glossopharyngeal ix

vagus x

hypoglossal xii

pharyngeal plexus ix x

ansa cervicalis c1 and c2

Question 14

phases of swallowing

Answer 14

3 or 4 phases

oral, pharyngeal, esophageal

pre-oral phase

oral phase divided into two, prepatory and transit

Question 15

oral prepatory phase

Answer 15

mastication

mostly volitional

refers to the processing of the bolus to render it swallowable

involves bolus manipulation, bolus containment - glossopalatal seal

Question 16

muscles and nerves of motor events of oral-prepatory phase

Answer 16

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)

Question 17

sensory nerves of oral-prepatory phase

Answer 17

tongue - anterior 2/3 sensory cn v, taste cn vii

posterior 1/3 sensory and taste cn ix

oral cavity - cn v and vii

Question 18

oral phase

Answer 18

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

Question 19

muscles and nerves of motor events of oral phase

Answer 19

palatoglossus - glossopalatal seal, pharyngeal plexus

extrinsic and intrinsic tongue muscles - drop and puch extrinsic, squeeze bolus from oral cavity intrinsic, hypoglossal nerve

Question 20

sensory nerves of oral phase

Answer 20

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

Question 21

pharyngeal phase

Answer 21

basic pattern is under involuntary control but may be modified with volition

rapid sequence of overlapping events including:

1. 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
2. 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
3. ues opening, tonic contraction must be terminated to allow passageway of the bolus through the esophagus, vagus and pharyngeal plexus
4. pressures on the descending bolus, the tongue, pharyngeal contraction and shortening (Hypoglossal, glossopharyngeal and pharyngeal plexus ix x)
5. 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)

Question 22

sensory nerves of pahryngeal phase

Answer 22

pharynx - pharyngeal plex ix x

larynx and trachea - x, cough reflex

Question 23

esophageal phase

Answer 23

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

Question 24

issue with pressure systems

Answer 24

components of swallowing do not act alone, deficits in oral phase will have effects on pharyngeal swallow regardless of specific pharyngeal deficits

Question 25

four valve system

Answer 25

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)

Question 26

dysphagia

Answer 26

disordered swallowing

Question 27

aspiration

Answer 27

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