L2 - Flashcards
What features does the pharynx extend to and from
Extends from the base of the skull to the lower border of the cricoid cartilage (C6)
What shape is the pharynx
Funnel shaped
what are the 3 parts of the pharynx
- Nasopharynx (air)
- Oropharynx (air + food)
- Laryngopharynx ( air and food sent in separate directions – food into the oesophagus, air into the larynx)
what is the pharynx continuous with?
The oesophagus
What is above, behind and on each side of the pharynx?
Above: The base of the skull
Behind: The bodies of the 6 upper cervical vertebra –> function to protect the pharynx
On each side:
- Great vessels and nerves of the neck –> Common carotid artery, IJV and vagus n. and others ig
- Styloid process and its associated structures
What are tonsils and what are the types of tonsils?
They are masses of lymphoid tissue (contains immune cells - B cells mainly i think) associated with the pharynx
Types:
- Nasopharyngeal tonsils (Adenoids) –> in roof of nasopharynx
- Palatine tonsils –> behind oropharynx/mouth
- Lingual tonsils –> behind the tongue at the base
Form a ring of defense against pathogens in the mouth
Walls/layers of the pharynx?
From the inside to outside - 5 layers :
1) mucous membrane
2) submucosal coat
3) Pharyngobasilar fascia - lining inside muscles
4) pharyngeal muscles
5) fascia - lining outside the muscles
What is the role of fascia in the pharynx?
It reinforces the larynx wall especially the spaces deficient in muscle (like the gaps thru which different structures leave the pharynx)
Are the pharyngeal musc. striated or unstriated? How many layers? what are they?
Where are the striated muscles arranged in the opp. way?
Striated but no evident voluntary control
- striated musc. arranged in 2 layers
- Outside - circular muscle (OC - remember the shit show cindy loves)
- Inside - longitudinal muscle
In the GIT -
Outside: Longitudinal muscles
Inside: Circular muscles
What are the pharyngeal muscles?
What are their origins?
What are their insertions?
What is their function?
What is their nerve supply?
NERVE SUPPLY –> all by Vagus nerve except stylopharyngeus muscle which is by glossopharyngeal nerve
Longitudinal muscles: Responsible for the elevation of the pharynx during swallowing
– Salpingopharyngeus (Origin - cartilage of Auditory tube/pharyngotympanic tube)
– Palatopharyngeus (origin - aponeurosis of soft Palate)
– Stylopharyngeus (origin - Styloid process)
Insertion (common): wall of pharynx
Circular muscles (3 constrictors): Responsible for constriction of pharynx
– Superior constrictor (Origin - Pterygoid hamulus, pterygomandibular raphe, mandible)
– Middle constrictor (Origin - Hyoid bone)
– Inferior constrictor (Origin - cricoid and thyroid cartilages of larynx)
Insertion (common) : Pharyngeal Raphe
What is the insertion for all the longitudinal musc? and circular muscles?
Longitudinal – wall of the pharynx
Circular (constrictor musc.) – Pharyngeal raphe (median fibrous raphe)
Which muscle has the cartilage of the auditory tube as an origin?
salpingopharyngeus musc.
(origin - auditory tube/pharyngotympanic tube)
Which pharyngeal muscle originates from the hyoid bone?
The middle constrictor muscle
Which muscles originate from cartilages in the pharynx and which cartilages?
Inferior constrictor musc –> cricoid and thyroid cartilages
Salpingopharyngeus musc –> Cartilage of the auditory/pharyngotympanic tube
where does the raphe extend from?
The skull
Which musc is innervated by the glossopharyngeal n. in the pharynx?
The stylopharyngeus
What allows for gaps in the wall of the pharynx?
What reinforces these gaps?
The overlapping of muscles (since they’re stacked like flower pots) allows for gaps in the wall
Allows for structures including nerves and vessels to pass thru
Fascia reinforces these gaps in the wall
Describe the motor and sensory innervation of the pharynx
Mostly thru the pharyngeal plexus (Vagus nerve - CN X and the glossopharyngeal nerve - CN IX)
Motor innervation:
- All by muscles by vagus nerve (CN X) except for the stylopharyngeus musc which is by the glossopharyngeal nerve (CN IX)
Sensory innervation:
- Nasopharynx: Maxillary nerve (V2 - trigeminal nerve)
- Oropharynx: Glossopharyngeal (CN IX)
- Laryngopharynx: Vagus (CN X) via the internal branch of the superior laryngeal nerve
What is the test commonly used for the glossopharyngeal nerve functioning (CN IX)
The gag reflex
- CN IX innervates the oropharynx
- Touch the back of the oropharynx/tongue
- Causes a reflex involving the symetrical elevation of the uvula
Describe the gag reflex pathway and name the nerves it can be used to test
Can be used to test for the glossopharyngeal and the vagus nerves
Reflex Pathway:
AFFERENT: Glossopharyngeal nerve provides sensory and afferent innervation to the posterior third tongue/oropharynx (sends msgs to the brain)
EFFERENT: The vagus nerve provides motor innervation to most of the pharyngeal muscles and palate
Thus msgs sent thru this nerve to elevate uvula
Location of the nasopharynx. oropharynx and laryngopharynx?
naso –> Lies behind the nasal cavity (chonae)
and above the soft palate
Oro –> Lies behind the oral cavity
Extends from the level of the soft palate (roof of mouth) to the upper margin of the epiglottis (cartilage of the larynx)
Laryngo –> Lies posterior to the larynx
Extends from the upper margin of the epiglottis and to the beginning of the oesophagus, anterior to the 6th cervical vertebra
Where does the opening of the pharyngotympanic tube lie?
in the lateral wall of the nasopharynx
alternate names for the auditory tube?
pharyngotympanic tube
eustachian tube
What is the function of the auditory tube?
The pharyngotympanic tube connects the nasopharynx with the middle ear
It thus allows ventilation of the middle ear and also functions to maintain equal air pressure between the outer and middle ear on either side of the eardrum.
Why do airline passengers suck on sweets when their ears get “blocked”?
The actions of yawning or swallowing can open the auditory tube. The muscles of the palate and the pharynx ‘pop open’ the auditory tube.
Describe the mechanism of swallowing
When you swallow -
– The wall of the pharynx is pulled forwards
– the soft palate is elevated
– This blocks the entry between the oropharynx and the nasopharynx –> Thus preventing food from moving into the nasopharynx
– the food then moves down into the laryngopharynx where it is continuous with the oesophagus
What tonsils are located in the nasopharynx?
The adenoid tonsils (pharyngeal tonsils)
- They are located in the roof of the nasopharynx
- They are lymphoid tissue (contain immune cells - act as a defense barrier)
- They atrophy as you age like any other lymphoid tissue
- They are at their max normal size during early childhood
- They are prone to infections during childhood
What happens to lymphoid tissue as you age?
They tend to atrophy – decrease in size
– tonsils are masses of lymphoid tissue that tend to atrophy as you age
when are the adenoids prone to infection? What happens as a result of infection?
During childhood
They may become enlarged as a result of infection
An enlargement of the adenoids may result in:
– blockage of the auditory tube: Leads to middle ear infections
– Blockage of the posterior nasal opening: Leads to mouth breathing and nasal speech
Surgical removal of enlarged adenoids may be required to improve hearing – adenoidectomy
What tonsils are located in the oropharynx? Where are they located specifically?
The palatine tonsils
Located on the lateral walls of the oropharynx
Between the palatoglossal and palatopharyngeal arches on either side of the oropharynx –> these arches are known as ‘the pillars’
what infection commonly occurs at the palatine tonsils?
Tonsilitis due to sore throat infections
what does a surgeon have to be careful of during tonsillectomy?
They have to be careful of a hemorrhage due to rich blood supply here
What is the sensory n supply to the nasopharynx?
Maxillary division of the trigeminal nerve (CN V2)
What is the sensory n supply to the oropharynx?
The glossopharyngeal nerve (CN IX) via the pharyngeal plexus (consists of the vagus and glossopharyngeal nerve branches)
What is the sensory n supply to the laryngopharynx?
The Vagus nerve – by the internal branch of the superior laryngeal branch
what are the branches of the vagus nerve?
Vagus nerve (CN X):
– Pharyngeal branch –> Motor supply to majority of the muscle of pharynx and the soft palate
– Superior Laryngeal branch –> It has internal and external divisions
– Recurrent laryngeal branch
pathway of vagus nerve?
Exits the base of the skull –> Travels thru the carotid sheath –> passes into the root of the neck
pathway of glossopharyngeal nerve?
Exits the base of the skull –> Descends on posterior surface of stylopharyngeus muscle –> passes thru a gap btwn superior and middle constrictors –> reaches the oropharynx and tongue
what is the distribution of the glossopharyngeal nerve?
– general sensation to posterior aspect of tongue and oropharynx
– sensory fibres from the carotid sinus and body
– motor supply to stylopharyngeus
– Parasympathetic fibres to parotid salivary gland
What gland do the parasympathetic fibres of glossopharyngeal supply?
The parotid salivary gland
describe the blood supply of the pharynx
Upper part by branches of the external carotid arteries
[Facial artery (and especially the palatine and tonsillar branches)
Ascending pharyngeal artery
Lingual artery
Maxillary artery]
Lower part by the subclavian arteries
What are the afferent and efferent limbs in the gag reflex?
Aff - Glossopharyngeal - sensory to oropharynx or posterior tongue
Eff - Vagus nerve - motor to a majority of the muscle of the pharynx and palate
A kid is breathing thru their mouth and has a nasaly voice along with a middle ear infection of further inspection. What could be the issue and what can be done?
inflammation of the adenoids – leading to blockage of the eustachian tube (middle ear infection) and also blockage of posterior nasal opening (nasaly voice and mouth breathing)
adenoidectomy
Where is the piriform fossa located?
on either side of the epiglottis at the entrance to the larynx
What is located between ‘the pillars’ ?
palatine tonsils
btwn palatoglossal and palatopharyngeal arches
A patient comes in violently gagging - what could have happened?
a sharp object disloged in piriform recess/fossa such as a fish bone
How can the auditory tube be opened?
by either swallowing or yawning
– muscles of pharynx and palate open the opening of the tube
Another name for the ear drum
tympanic membrane
What can result in a middle ear infection? what is another name for it?
inflammation of adenoids – blockage of auditory tube
Otitis media
Blockage of What can result in mouth breathing and nasal speech?
posterior nasal openings
What is the surgical removal of adenoids? What would it improve?
adenoidectomy
May be required to improve hearing
Improve nasal speech, breathing (no more mouth breathing) and get rid of a middle ear infection if present
How may the pharyngeal plexus be damaged? What can this result in??
Can be damaged due to a brainstem injury or a stroke
May cause a difficulty in swallowing
What happens if the posterior nasal opening is blocked?
Nasal speech and mouth breathing
What might snoring be the result of?
What gap do the stylopharyngeus muscle and glossopharyngeal nerve pass thru?
Between the superior and middle pharyngeal constrictor muscles, the stylopharyngeus muscle and the glossopharyngeal nerve pass through.