Mouth, pharynx, oesophagus Flashcards
Meaning of cervical viscera
internal organs in the neck
3 overall functions of cervical visceral
Respiratory, Endocrine, Alimentary
Structure of the pharynx
Muscular tube from base of skull to oesophagus (C6)
what are the 3 sections of the pharynx?
Nasopharynx, oropharynx, laryngopharynx
Function of pharynx
Digestive and respiratory function. Conducts air. Muscles contract to propel food to oesophagus
Which part of the pharynx is continuous with the nasal cavity?
nasopharynx
Which duct drains into the nasal cavity and then into the nasopharynx?
Nasolacrimal duct (tear ducts drains from corner of eye)
Which structures are closely associated to the nasopharynx?
Opening of auditory tube, tubal tonsils, pharyngeal tonsils (adenoids)
Function of auditory tube
equalises pressure between inner and outer environment (ear pop)
Function of tubal tonsils
lymphatic tissue that protects against pathogens entering via nose and ear
Function of pharyngeal tonsils / adenoids
Protect against pathogens that enter via nose
Location of tubal tonsils
Posterior to opening of auditory tube
Location of pharyngeal tonsils / adenoids
Posterior and superior to nasopharynx
Which tonsils enlarge between the age of 3-8 and regress as immunity develops so that they may not be visible in adults?
Pharyngeal tonsils
Location of oropharynx
From soft palate to base of tongue / epiglottis
Function of epiglottis
Closes like a flap during deglutition to prevent entry of food to larynx and trachea
Name of the two arches/folds that make up the pillars of fauces
Palatoglossal and palatopharyngeal arches/fold
Location of palatoglossal arch
Anterior arch connecting soft palate to lateral sides of tongue
Function of palatoglossal arch
Contains palatoglossus muscle which pulls the soft palate to the tongue when swallowing to prevent the entry of food to nose
Location of palatopharyngeal fold
Posterior fold which connects soft palate to wall of oropharynx. Located more medially that palatoglossal fold
Function of palatopharyngeal fold
Contains palatopharyngeus muscle that tenses soft palate and draws pharynx anteriorly when swallowing
Location of palatine tonsils
in tonsillar fossa which is found between the palatoglossal and palatopharyngeal folds and the tongue
Which tonsils are most affected by a sore throat?
Palatine tonsils
What is the name of the ring of lymphatic tissue found in the soft palate and pharynx?
Waldeyer’s ring
Which tonsils make up Waldeyer’s ring?
Palatine, pharyngeal, tubal, lingual tonsils
Where are the lingual tonsils located?
Posterior third of tongue
Location of laryngopharynx
From epiglottis to the level of cricoid cartilage (which is below the thyroid cartilage)
Which part of the pharynx forms part of the laryngeal inlet?
Laryngopharynx
What is the name of the small depressions on either side of the larynx opening?
Piriform fossa
What is the clinical relevance of the Piriform fossa?
Most common region (70%) of laryngopharyngeal cancer
Which muscles propel food through the pharynx?
Superior constrictor, middle constrictor, inferior constrictor muscles
Which directions do pharyngeal constrictor muscles run in?
circularly on the outside, longitudinally on the inside
Arrangement of pharyngeal constrictor muscles
Like stacked glasses
Mode of action of pharyngeal constrictor muscles
contract sequentially from superior to inferior in order to propel food to oesophagus via peristalsis
Which nerve innervates the pharyngeal constrictor muscles?
Pharyngeal plexus and the pharyngeal branch of the vagus nerve (CN X)
Location of superior constrictor
Base of skull and mylohyoid (muscle that form floor of mouth)
Where does the middle constrictor originate from?
Hyoid bone
What is the hyoid bone?
U-shaped bone in anterior neck not attached to other bones, only ligaments and muscle attachment.
Where does the inferior constrictor originate from?
From the cricoid cartilage and thyroid cartilage in the larynx
What are the motor nerves that supply muscles of the pharynx?
Vagus (CN X) except stylopharyngeus (CN IX - glossopharyngeal nerve) and one tensor (veli palatini CN V - trigeminal nerve)
What is the main sensory nerve of the pharynx?
Glossopharyngeal nerve (CN IX)
What is the main structure innervating the pharynx?
Pharyngeal plexus (made of glossopharyngeal CN IX, vagus CN X, maxillary CNII nerves)
Name of posterior attachment of pharyngeal constrictors
Pharyngeal raphe
What is otitis media?
Middle ear infection in which auditory tube becomes blocked an inflamed. More common in children as they have a shorter auditory tube.
Which tonsils are most commonly affected by tonsilitis?
Palatine tonsils
Cause of tonsillitis
bacterial or viral infection
Damage to which structures must be avoided during a tonsillectomy?
External palatine vein, tonsillar artery, internal carotid artery, glossopharyngeal nerve (CN IX)
What is the oesophagus?
A 20-25cm muscular tube connecting the pharynx to the stomach
Location of oesophagus
Lies in the neck, thorax and abdomen posterior to the trachea and heart.
Which structure can impact the size of the oesophagus?
The trachea - as it expands during inhalation the oesophagus can become compressed
At which point does the oesophagus pierce the diaphragm?
Oesophageal hiatus (about tenth thoracic vertebrae)
Name of sphincters in the oesophagus
Upper oesophageal sphincter and lower oesophageal sphincter (prevent back flow of bolus)
What makes up the upper oesophageal sphincter?
Fibres from inferior constrictor muscle and skeletal muscle (despite being involuntary)
Which feature of the lower oesophageal sphincter supports its function/physiology?
Angle at which oesophagus connects to stomach
Alternative names of the lower oesophageal sphincter
Gastroesophageal sphincter, cardiac sphincter
layers of the oesophagus
non-keratinised stratified squamous epithelium, lamina propria, muscularis mucosae, submucosa (containing submucosal glands), muscularis propria
Why is the oesophageal epithelium stratified, squamous and non-keratinised?
Stays moist to lubricate movement of food. Multiple layers protect against mechanical damage
Function of muscularis mucosae
Enhances nutrient supply and aids secretion via small movements
Structure of muscularis propria
Inner circular layer, outer longitudinal layer of muscle
What are the muscle types in the oesophagus?
Transitions from skeletal in upper third, to mixed in middle, smooth in lower third
Which glands are found in the submucosa of the oesophagus?
Mucus secreting glands
Clinical relevance of dysfunction of the lower oesophageal sphincter?
Can cause Gastro-oesophageal reflux disease (GORD)
What can GORD result in?
Metaplasia, Barrett’s oesophagus, dysplasia, oesophageal cancer
What is metaplasia?
abrupt change in epithelium type
What is Barrett’s oesophagus?
When oesophageal epithelium changes from stratified squamous to simple columnar epithelium
What is dysplasia?
abnormal cell growth resulting in unequal cell size, excess pigment and higher mitotic figures. Dysplasia increases the risk of oesophageal carcinoma.
2 roles of deglutition
moves food to stomach and prevents entry to airway
Oral phase of deglutition
Food is moved posteriorly to pharyngeal surface of tongue approaching oropharynx. Liquid remains infront of pillars before being swallowed.
Pharyngeal phase of deglutition
The bolus moves from the oropharynx to the laryngopharynx via contraction of 3 constrictor muscles. Soft palate rises, epiglottis is depressed (closes), vocal cords contract using pharyngeal constrictors. Prevents entry to larynx. UOS relaxes to allow passage into oesophagus.
Oesophageal phase of deglutition
UOS constricts pushing bolus down. Peristalsis as oesophagus constricts above the bolus and dilates and shortens below it. LOS relaxes - angle allows controlled movement into cardia.
What is dysphagia?
Difficulty swallowing
Causes of dysphasia
Neuromuscular disease of the constrictor muscles (MS, stroke). Obstruction from srictures (scarring from chronic inflammation), tumours, developmental abnormality e.g. fistula.
3 possible tracheo-oesophageal fistula
- lower oesophagus connects with trachea instead of upper oesophagus
- oesophagus forms in two parts from the pharynx and the stomach but don’t meet
- oesophagus connected to trachea - food passes into trachea causing choking, swollen abdomen, blue, frothing at mouth.
Fistula definition
Abnormal connection between 2 epithelial lined hollowed organs e.g. blood vessels, intestines
