Functions of the mouth and oesophagus

Question 1

What are the simple functions of the mouth and oropharynx?

What is the simple function of the oesophagus?

Answer 1

Mastication - increases SA for digestion
Intitiation of carbohydrate and fat metabolism
Lubrication

Conduit - connection between mouth and stomach

Question 2

Which enzymes are secreted by the salivary glands?

Answer 2

amylase and lipase

Question 3

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?

Answer 3

Antibacterial function:

• IgA - antibodies bind to pathogenic antigen
• Lactoferrin - binds to iron and is bactericidal
• Lysozyme - attack bacterial cell walls –> cell lysis

Question 4

What are the 2 cell types of salivary glands and what do they do?

Answer 4

acinar cells - enzymes

ductal cells - mucous, secrete water and electrolytes

Question 5

Describe the type of saliva produced by each salivary gland. Which salivary gland produces saliva in the greatest volume?

Answer 5

Parotid - serous, water
Submandibular - mixed, slightly viscous
Sublingual - mucous, very viscous

greatest volume = submandibular

Question 6

What are the 3 functions of saliva?

Answer 6

lubrication
hydration - oral mucosa, keeps cells alive
cytoprotection - protects cells from damage

Question 7

What is the function of salivary duct cells?

Answer 7

Modify the secretion of acinar cells

Make saliva hypotonic and alkaline

Question 8

Why is it important that saliva is alkaline? x2

Answer 8

Protects teeth from bacterial acid

Neutralises gastric acid that refluxes into the oesophagus

Question 9

What is Sjogrens’s syndrome?
Who does it most commonly affect?
Which other disease is it associated with?

Answer 9

Autoimmune attack of salivary glands which results in dry mouth (xerostomia) and eyes.
Commonly affects women, associated with rheumatoid arthritis

Question 10

How is mumps associated with the salivary glands?

It is associated with orchitis. What is this?

Answer 10

Parotitis - inflammation/infection of parotid gland
Associated with orchitis - inflammation of the testicles
Prodrome of headache and fever

Question 11

What is the parasympathetic innervation of each salivary gland?

Answer 11

Parotid - glossopharyngeal, otic ganglion
Submandibular - hypoglossal, submandibular ganglion
Sublingual - hypoglossal, submandibular ganglion

Question 12

What is the sympathetic innervation of the salivary glands and what does it result in?

Answer 12

Thoracic sympathetics –> superior cervical ganglion

Sympathetic innervation stimulates vasoconstriction and thick mucous secretion

Question 13

What are the 4 phases to swallowing?

Answer 13

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

Question 14

What 4 cranial nerves make up the swallowing centre in the medulla/

Answer 14

trigeminal (V)
glossopharyngeal (IX)
vagus (X)
hypoglossal (XII)

Question 15

What are the symptoms/signs of pseudobulbar palsy and bulbar palsy?

Answer 15

dysphagia
altered speech
loss of gap reflex –> frequent aspiration

Question 16

What is the difference between pseudobulbar palsy and bulbar palsy, in terms of upper or lower motor neurone, anatomical site and causes?

Answer 16

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

Question 17

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?

Answer 17

Contains mucos, 2 layers of muscle
No serosa, no mesentery
No tough coating like rest of GI tract so oesophageal tutors are very aggressive

Question 18

Describe in terms of embryology how tracheooesophageal fistulas and oeosophageal atresia occur?

Answer 18

The trachea develops as lungs bugs from the oesophagus
Fistulas - abnormal connection between trachea and oesophagus
Atresia - disconnection of upper and lower oesophagus

Question 19

What are the 2 physiological and 3 anatomical mechanisms that promote gastro-oesophageal sphincter competence?

Answer 19

Physiological
- LOS tone
- intra-abdominal length of oesophagus, protected from changes in IA pressure
Anatomical
- crural sling
- acute angle of His
- mucosal rossette

Question 20

What are the causes of GORD?

Answer 20

obesity
hiatus hernia
drugs that lower LOS tone (antichollinergic, beta agonist, benzodiazepines)
pregnancy
Zollinger-Ellison syndrome (gastrin secreting tumour)

Question 21

What are the potential chronological outcomes of GORD?

Answer 21

oesophagitis
barrett’s metaplasia
oesphageal adenocarcinoma

Question 22

What is the treatment for GORD?

• conservative
• medical
• surgical

Answer 22

Conservative - weight loss, diet, alcohol, raise head of bef
Medical - PPI’s, H2 blockers, antacids, alginates (gaviscon)
Surgical - fundoplication, repair hiatus hernia, vagotomy (historic)

Question 23

Define metaplasia.

Answer 23

change of epithelial cell type in response to environmental stress

Question 24

In Barret’s metaplasia what is the epithelial cell type change?

Answer 24

Squamous –> columnar

Question 25

What are the two types of oesophageal cancers and what are their causes?

Answer 25

Squamous cell carcinoma - alcohol, tobacco, strictures, alchalasia
Adenocarcinoma - GORD

Question 26

What is achalasia?

What is the treatment?

Answer 26

Failure of LOS to relax, caused by loss of myenteric plexus at LOS
Botox injections at LOS, oesophageal dilation, Hellers myotomy

Question 27

What is a pharyngeal pouch?
What is its cause?
Treatment?

Answer 27

posterior defect between cricopharyngeus and inferior constrictor
Causes: traction diverticulum, trumpet players

Question 28

What can cause an oesophageal rupture?
What are the clinical features?
Treatment/

Answer 28

endoscopy, trauma, vomiting
chest ppain, subcutaneous emphysema, sepsis, pleural effusion
Consecrative with chest drainage, surgery

Question 29

What are oesophageal varies?
What causes them?
What are the possible complications?
Treatment?

Answer 29

• dilated submucosal veins in lower oesophagus
• due to portal hypertension, and others
• bleeding
• beta blockers, nitrates decrease portal pressure, liver transplant,