Pharynx Flashcards
What are the pharyngeal muscles?
Outer circular (incomplete ring)
- superior, middle and inferior constrictors (propel food) attached to midline Raphe
- lower horizontal fibres: cricopharyngeus
Inner longitudinal muscles
- stylopharyngeus, palatopharyngeus and salpingopharyngeus (shorten pharynx)
What are the divisions of the pharynx?
Nasopharynx:
- base of skull to soft palate: anterior is nasal cavity (level C1)
- respiratory function: pseudostratified ciliated epithelia + goblet cells
- superior aspect is tonsillar ring (waldeyers ring) form adenoids
- opening of Eustachian tube
Oropharynx:
- soft palate to epiglottis: anterior is oral cavity (level C2-3)
- digestive function: stratified squamous epithelia non K
- location of palatine tonsils
Laryngopharynx:
- epiglottis to cricoid cartilage: anterior is larynx (level C4-6)
- stratified squamous epithelia non K - continuous with oesophagus
How are the pharyngeal muscles innervated?
Pharyngeal plexus of vagus and glossopharyngeal nerves, plus superior cervical ganglion fibres (sympathetic)
SENSORY
- nasopharynx: trigeminal nerve (Opthalmic and maxillary branches)
- oropharynx: glossopharyngeal (CN IX)
- laryngopharynx: hypoglossal (CN XII)
MOTOR
- laryngopharynx: all pharyngeal muscles are vagus (CN X) except stylopharyngeus (CN IX)
What is the blood supply to the pharynx?
External carotid artery
- ascending pharyngeal artery
- lingual artery
- facial artery
- maxillary artery
Drainage via pharyngeal venous plexus to internal jugular vein
Describe the phases of swallowing
Voluntary phase
- bolus to back of pharynx by tongue
Pharyngeal phase
- pressure receptors triggered
- breathing inhibit and larynx rises
- glottis closes and upper oesophageal sphincter opens
Oesophageal phase
- upper third is striated muscle (voluntary)
- lower two thirds smooth muscle under parasympathetic control
- peristaltic wave pushes food to stomach in 9 seconds
- lower oesophageal sphincter opens
What is the gag reflex?
Tests pharyngeal innervation and musculature
- touching back of oropharynx
- afferent: glossopharyngeal CN IX
- efferent: vagus CN X
What are the adenoids?
Lymphoid tissue at junction of roof and posterior nasopharynx
- max size between 3-8yrs then regress
- enlarge with bacterial/viral infections
- may block Eustachian tube by adenoidal enlargement, resulting in otitis media
- enlargement may also cause nasal obstruction, obstructive sleep apnoea and snoring
What are the palatine tonsils?
Lymphoid tissue found within the tonsillar fossa between two arches
- anterior palatoglossal arch and posterior palatopharyngeal arch
- enlarged by viral infections
- lymphoid drainage by jugulo- digastric node (tonsillar and mandible)
What is a tonsillectomy?
Tonsil removal following 5 episodes of inflammation in a year for two consecutive years
- risks of bleeding due to damage to external palatine vein
- internal carotid artery and glossopharyngeal nerve lie lateral to tonsillar fossa
What is quinsy?
Peri tonsillar abscess
- uvula is pushed to once side
- requires drainage of the abscess
How can food obstruction occur?
Food can become lodged in the oropharynx (within the valeculla) or within the laryngopharynx (within the piriform fossa)
