The pharynx and tonsils Flashcards
What is the pharynx?
- 12-14cm long musculomembranous tube
- between nasal cavity and entrance to larynx and oesophagus
- partially surrounded by muscle
What is the function of the pharynx?
has a role in articulation and respiration
What regions is the pharynx divided into?
- nasopharynx
- oropharynx
- laryngopharynx
Where does the nasopharynx extend between?
the nose and soft palate
Where does the oropharynx extend between?
soft palate to tip of epiglottis
Where does the laryngopharynx extend between?
epiglottis to cricoid cartilage
What does the nasopharynx contain?
- pharyngeal tonsil (adenoids)
- opening of auditory tubes
- tubal tonsils
Where does the oropharynx open into the mouth?
through the oropharyngeal isthmus
Where does the oropharynx start?
by the palatoglossal arch
What does the lateral wall of the oropharynx contain?
the palatopharyngeal arch and palatine tonsil
Where is the oropharynx relative to the spine?
level with the bodies of the second, and upper part of third vertebrae
Where is the laryngopharynx?
behind the entire length of the larynx, and is continuous with the oesophagus
What is in the upper part of the anterior wall of the laryngopharynx?
the laryngeal inlet
Where is the laryngopharynx in relation to the spine?
- at rest, extends between 3rd and 6th cervical vertebral body
- during swallow, is elevated considerably by hyoid elevators
What are the types of muscles of the pharynx?
- circular (inner muscles)
- longitudinal (outer muscles)
How do the muscles of the pharynx support peristalsis?
through constriction (circular) and elevation (longitudinal)
What are the circular muscles of the pharynx?
- superior constrictor
- medial constrictor
- inferior constrictor
- cricopharyngeus
What is the function of the circular muscles of the pharynx?
act in sequence from top to bottom to propel bolus through pharynx
What are the longitudinal muscles of the pharynx?
- stylopharyngeus
- palatopharyngeus
- salpingopharyngeus
What CN innervates the stylopharyngeus?
CNIX - glossopharyngeal
What CN innervates the palatopharyngeus?
CNX vagus
What CN innervates the salpingopharyngeus?
CNX vagus
What is the function of the longitudinal muscles of the pharynx?
- elevate the larynx in wallow
- shorten and widen the pharynx in swallow
What innervates the pharynx?
A plexus (fine network of nerves) which runs under the lining (sensory) and muscles (motor) of the pharynx
What is the pharyngeal plexus formed from?
- pharyngeal branches of glossopharyngeal nerve (CNIX)
- pharyngeal branches of vagus nerve (CNX)
- branches from external laryngeal nerve (a branch of vagus)
- sympathetic fibres from superior cervical ganglion
What supplies sensory innervation to the main chunk of the pharynx?
glossopharyngeal nerve - CN IX
What supplies sensory innervation to anterior and superior aspect of nasopharynx?
maxillary nerve - branch V2 of trigeminal nerve CNV
What supplies sensory innervation to inferior aspect of laryngopharynx?
internal branch of superior laryngeal nerve (branch of vagus CNX)
What are the clinical applications of nerve damage to the pharynx?
- damage to nerve supply causes dysphagia
- damage to IX sensory supply = difficulty initiating swallow, absent gag reflex
- damage to motor CNX = difficulty in smooth transit of material from mouth to oesophagus
What are tonsils?
accumulations of lymphoid tissue
What is the purpose of lymphoid tissue?
protects GI and respiratory tracts because lymphocytes produce antibodies in response to bacteria and their toxins
What happens to the tonsils of there is an infection?
they enlarge
What are the main groups of tonsillar tissue?
- palatine tonsils (paired)
- pharyngeal tonsils (the adenoids)
- lingual tonsils
- tubal tonsils (paired)
Where are the palatine tonsils?
between the palatoglossal and palatopharyngeal arches just in the oropharynx
Where are the pharyngeal tonsils?
in the posterior wall of the nasopharynx
Where are the tubal tonsils?
around the entrance to auditory tube but may be very small or not present
Where are the lingual tonsils?
under the mucosa of the posterior third of tongue
What connects the tonsils?
Waldeyers tonsilar ring
What is the difference in tonsil size with age?
tonsils in children are about twice as large as adults - can cause considerable blockage if enlarged
What can enlarged adenoids cause?
- sinusitis, auditory tube dysfunction, middle ear infection, sleep apnoea
- open mouth breathing and hyponasality
What can enlargement of the palatine tonsils cause?
can interfere with soft palate elevation and cause hypernasality
What can pharyngeal and tubal tonsillar enlargement cause?
middle ear infections and glue ear from preventing the auditory tube opening
What is a tonsillectomy used for?
- chronic tonsilitis and complications
- sleep apnoea
