A26 - Pharynx and Gag Reflex Flashcards
what is the pharynx?
space between the base of the cranium and the inferior border of C6 that connects the nose and mouth above to the larynx and oesophagus below
what is the pharynx involved in?
- breathing
- speech
- coughing
- sneezing
- vomiting
- swallowing
- gagging
what is the protective feature of the pharynx?
against aspiration and inhalation of solids/liquids into the lungs
what are the regions of the pharynx?
nasopharynx - behind the nasal cavity at the opening of the pharyngotympanic tube
oropharynx - behind the oral cavity
laryngopharynx - behind the larynx
what makes up the respiratory tract?
nasal cavity
oral cavity
larynx
trachea
what does the oral cavity and the oesophagus make up?
alimentary tract
what are the layers surrounding the retropharyngeal space ?
pharynx > pharyngeal muscle > buccopharyngeal fascia > retropharngeal space > alar fascia > retropharyngeal space > pre-vertebral fascia > pre-vertebral muscle > anterior longitudinal ligament
what are the three circular muscles of the pharynx?
- superior constrictor
- middle constrictor
- inferior constritor
where do the constrictor muscles insert ?
midline raphe
what supplies the majority of the muscles of the pharynx?
CN X - pharyngeal plexus
what does pharyngo-basilar fascia cover ?
internal aspect of the circular muscles
what covers the external surface of the circular muscles?
bucco-pharyngeal fascia
where does the superior constrictor muscle attach ?
- pterygoid hamulus
- pterygomandibular raphe
mylohyoid line
what muscle attaches to the greater horn of the hyoid ?
middle constrictor
where does the inferior constrictor muscle attach?
thyroid cartilage (oblique line) and the cricoid cartilage
what vessels and muscles pass through the “ gateway to the mouth?”
- CN IX
- lingual artery
- stylopharyngeus muscle
where is the “gateway to the mouth” located ?
between the superior and middle constrictor muscle
what is the only muscle supplied by CN IX?
stylopharyngeus
What connects the nasopharynx up to the middle ear?
Pharyngotympanic Tube
what longitudinal muscles insert onto the posetrior border of throid cartilage and elevate pharynx and larynx?
- stylopharyngeus
- palataopharyngeus
- salpingopharyngeus
what nerve supplies the palataopharyngeus
and salpingopharyngeus muscles ?
CN X
what is the space between the base of posteior tongue ?
vallecula
what is the choana?
posterior opening of the nasal cavity
what is important about the piriform fossa ?
located inferior to the epiglottis and if food is stuck in here it can press on laryngeal nerves and affect the voice
What is the elastic cartilage that guards the opening of the larynx?
epiglottis
what tonsils are located in the oropharynx ?
palatine tonsils
where are pharyngeal tonsils located?
nasopharynx
what innervates the pharyngeal plexus ?
motor - mainly CN X
sensory - mainly CN IX
what innervates the mucosa of the nasopharynx ?
CN V2 - anterior and superior auditory tube
CN IX
what innervates the oropharynx ?
CN IX inculdes tonsillar fossa and posteior tongue
what innervates the laryngopharynx?
CN XI - superior eppiglittis
CN X
what stumulates sensory nerve fibres of CN IX and tried to close of the oropharynx ?
gag reflex
what muscles are involved in teh gag reflex?
- constrictors of pharynx (CN X)
- longitudinal muscles of - pharynx (CN IX and X)
- tongue and soft palate
what is the relevance of the gag reflex to dentists ?
- patients with sensitive throats
- recurrent gag reflex can make treatment very difficult
- careful technique, relaxed patient
describe the first stage of swallowing
Food bolus squeezed to back of mouth
Tongue against palate
describe the second stage of swallowing
Nasopharynx closed off
Larynx elevated
Pharynx enlarged to receive bolus
describe the thrid stage of swallowing
Pharyngeal constrictors contract sequentially
Epiglottis deflects bolus
descirbe the fourth stage of swallowing
Bolus moves into oesophagus
