Functions of the mouth and oesophagus Flashcards
What are the simple functions of the mouth and oropharynx?
What is the simple function of the oesophagus?
Mastication - increases SA for digestion
Intitiation of carbohydrate and fat metabolism
Lubrication
Conduit - connection between mouth and stomach
Which enzymes are secreted by the salivary glands?
amylase and lipase
The main components of saliva are mucous and fluid. It also contains IgA, lysozyme and lactoferrin. What are the functiosn of these three lesser components?
Antibacterial function:
- IgA - antibodies bind to pathogenic antigen
- Lactoferrin - binds to iron and is bactericidal
- Lysozyme - attack bacterial cell walls –> cell lysis
What are the 2 cell types of salivary glands and what do they do?
acinar cells - enzymes
ductal cells - mucous, secrete water and electrolytes
Describe the type of saliva produced by each salivary gland. Which salivary gland produces saliva in the greatest volume?
Parotid - serous, water
Submandibular - mixed, slightly viscous
Sublingual - mucous, very viscous
greatest volume = submandibular
What are the 3 functions of saliva?
lubrication
hydration - oral mucosa, keeps cells alive
cytoprotection - protects cells from damage
What is the function of salivary duct cells?
Modify the secretion of acinar cells
Make saliva hypotonic and alkaline
Why is it important that saliva is alkaline? x2
Protects teeth from bacterial acid
Neutralises gastric acid that refluxes into the oesophagus
What is Sjogrens’s syndrome?
Who does it most commonly affect?
Which other disease is it associated with?
Autoimmune attack of salivary glands which results in dry mouth (xerostomia) and eyes.
Commonly affects women, associated with rheumatoid arthritis
How is mumps associated with the salivary glands?
It is associated with orchitis. What is this?
Parotitis - inflammation/infection of parotid gland
Associated with orchitis - inflammation of the testicles
Prodrome of headache and fever
What is the parasympathetic innervation of each salivary gland?
Parotid - glossopharyngeal, otic ganglion
Submandibular - hypoglossal, submandibular ganglion
Sublingual - hypoglossal, submandibular ganglion
What is the sympathetic innervation of the salivary glands and what does it result in?
Thoracic sympathetics –> superior cervical ganglion
Sympathetic innervation stimulates vasoconstriction and thick mucous secretion
What are the 4 phases to swallowing?
oral preparatory phase - mastication/manipulation
oral phase - tongue propels food posteriorly –> pharyngeal swallow is triggered
pharyngeal phase - pharyngeal swallow, closure of glottis, cessation of breathing, relaxation of UOS
oesophageal phase - peristalsis carries bolus to stomach
What 4 cranial nerves make up the swallowing centre in the medulla/
trigeminal (V)
glossopharyngeal (IX)
vagus (X)
hypoglossal (XII)
What are the symptoms/signs of pseudobulbar palsy and bulbar palsy?
dysphagia
altered speech
loss of gap reflex –> frequent aspiration
What is the difference between pseudobulbar palsy and bulbar palsy, in terms of upper or lower motor neurone, anatomical site and causes?
Pseudobulbar
- UMN i.e. preganglionic
- cerebral cortex fibres pass to medulla via corticobulbar pathway
- CVA of cerebral cortex, head injury, MS, high brain stem tumour
Bulbar
- LMN i.e. postganglionic
- LMN of CN IX, X, XI, XII
- CVA of medulla, MN disease, guillain-barre, polio, glioma of brain stem
In terms of the layers of the oesphagus, what layers does it contain and what does it lack? What is the implication of this lack of layers?
Contains mucos, 2 layers of muscle
No serosa, no mesentery
No tough coating like rest of GI tract so oesophageal tutors are very aggressive
Describe in terms of embryology how tracheooesophageal fistulas and oeosophageal atresia occur?
The trachea develops as lungs bugs from the oesophagus
Fistulas - abnormal connection between trachea and oesophagus
Atresia - disconnection of upper and lower oesophagus
What are the 2 physiological and 3 anatomical mechanisms that promote gastro-oesophageal sphincter competence?
Physiological - LOS tone - intra-abdominal length of oesophagus, protected from changes in IA pressure Anatomical - crural sling - acute angle of His - mucosal rossette
What are the causes of GORD?
obesity
hiatus hernia
drugs that lower LOS tone (antichollinergic, beta agonist, benzodiazepines)
pregnancy
Zollinger-Ellison syndrome (gastrin secreting tumour)
What are the potential chronological outcomes of GORD?
oesophagitis
barrett’s metaplasia
oesphageal adenocarcinoma
What is the treatment for GORD?
- conservative
- medical
- surgical
Conservative - weight loss, diet, alcohol, raise head of bef
Medical - PPI’s, H2 blockers, antacids, alginates (gaviscon)
Surgical - fundoplication, repair hiatus hernia, vagotomy (historic)
Define metaplasia.
change of epithelial cell type in response to environmental stress
In Barret’s metaplasia what is the epithelial cell type change?
Squamous –> columnar
What are the two types of oesophageal cancers and what are their causes?
Squamous cell carcinoma - alcohol, tobacco, strictures, alchalasia
Adenocarcinoma - GORD
What is achalasia?
What is the treatment?
Failure of LOS to relax, caused by loss of myenteric plexus at LOS
Botox injections at LOS, oesophageal dilation, Hellers myotomy
What is a pharyngeal pouch?
What is its cause?
Treatment?
posterior defect between cricopharyngeus and inferior constrictor
Causes: traction diverticulum, trumpet players
What can cause an oesophageal rupture?
What are the clinical features?
Treatment/
endoscopy, trauma, vomiting
chest ppain, subcutaneous emphysema, sepsis, pleural effusion
Consecrative with chest drainage, surgery
What are oesophageal varies?
What causes them?
What are the possible complications?
Treatment?
- dilated submucosal veins in lower oesophagus
- due to portal hypertension, and others
- bleeding
- beta blockers, nitrates decrease portal pressure, liver transplant,
