Functions of the Mouth & Oesophagus Flashcards
Define digestion.
The conversion of dietary nutrients into a form that the small intestine can absorb.
What is the function of mastication?
To increase surface area for digestion.
Which enzymes initiate carbohydrate and fat metabolism?
Salivary amylase and lipase.
List the names of all of the salivary glands.
1 - Parotid (and accessory parotid).
2 - Sublingual.
3 - Submandibular.
List 3 secretions of salivary glands that serve antibacterial functions.
1 - IgA.
2 - Lysozymes.
3 - Lactoferrin.
What is the function of acinar cells in salivary glands?
To produce enzymes.
What is the function of ductal cells in salivary glands?
1 - To produce mucus (goblet cells).
2 - To secrete water and electrolytes.
Give the % of total secretion represented by the parotid, submandibular and sublingual glands.
Parotid - 20%
Submandibular - 70%
Sublingual - 10%
How are the secretions of the parotid gland conveyed to the mouth?
Through the parotid duct.
Are the secretions of the parotid gland serous, mucous or mixed?
Serous.
Are the secretions of the submandibular gland serous, mucous or mixed?
Mixed
Are the secretions of the sublingual gland serous, mucous or mixed?
Mucous
How does lactoferrin work?
Lactoferrin binds iron, limiting the amount of ions available for microorganisms’ metabolism.
Why is saliva hypotonic and alkaline?
Because salivary duct cells extract Na+ and Cl- from the blood and secrete K+ and HCO3-.
List 2 advantages of saliva being alkaline.
1 - Protects teeth from bacterial acids.
2 - Neutralises gastric acid that refluxes into the oesophagus.
What is Sjögren’s syndrome?
Who is most commonly affected?
What is the syndrome associated with?
- An autoimmune attack of salivary and tear glands which results in dry mouth and eyes.
- Commonly affects women and is associated with rheumatoid arthritis.
What is parotitis?
- Inflammation of a parotid gland.
- Associated with mumps.
In which ganglion does the facial nerve synapse with the post-synaptic counterpart that is responsible for the stimulation of the submandibular and sublingual glands?
The submandibular ganglion.
In which ganglion does the glossopharyngeal nerve synapse with the post-synaptic counterpart that is responsible for the sitmulation of the parotid gland only?
The otic ganglion.
In which ganglion do thoracic sympathetics synapse with the post-synaptic counterparts that are responsible for the sitmulation of all salivary glands?
The superior cervical ganglion.
What is xerostomia?
Dry mouth resulting from reduced or absent saliva flow.
What are the 4 phases of swallowing?
1 - Oral preparatory phase.
2 - Oral phase.
3 - Pharyngeal phase.
4 - Oesophageal phase.
Describe the oral preparatory phase of swallowing.
Food is masticated in the mouth to reduce to a consistency which can be swallowed.
Describe the oral phase of swallowing.
The tongue propels the bolus posteriorly until the pharyngeal phase is triggered.
Describe the pharyngeal phase of swallowing.
The bolus is transported through the pharynx with:
- Coordinated closure of the glottis via movement of the epiglottis.
- Cessation of breathing.
- Relaxation of the upper oesophageal sphincter.
Describe the oesophageal phase of swallowing.
Oesophageal peristalsis carries the bolus from the upper oesophageal sphincter through the oesophagus to the lower oesophageal sphincter.
Which 4 cranial nerves compose the swallowing centre in the medulla oblongata?
1 - Trigeminal nerve (V)
2 - Glossopharyngeal nerve (IX)
3 - Vagus nerve (X)
4 - Hypoglossal nerve (XII)
Is pseudobulbar palsy a result of damage to an upper or lower motoneurone?
Upper.
Is bulbar palsy a result of damage to an upper or lower motoneurone?
Lower.
List 3 symptoms of pseudobulbar and bulbar palsy.
1 - Difficulty in swallowing.
2 - Altered speech.
3 - Loss of gag reflex, can lead to aspiration of food / fluid into the trachea.
Briefly summarise the embryological development of the trachea.
- The trachea develops as lung buds from the oesophagus.
- As the trachea matures it comes to lie anterior to the oesophagus.
List 2 congenital problems of the trachea.
1 - Tracheoesophageal fistula (abnormal passageway between the trachea and oesophagus).
2 - Oesophageal atresia.
What is GORD?
- Gastro-oesophageal reflux disease.
- Chronic symptoms of mucosal damage produced by the abnormal reflux in the oesophagus.
List 5 causes of GORD.
1 - Obesity.
2 - Hiatus hernia (part of the stomach slides or rolls up to the chest).
3 - Drugs that lower tone at lower oesophageal sphincter.
- Anti cholinergic.
- Beta agonists.
- Benzodiazepenes.
4 - Pregnancy.
5 - Zollimger Ellison syndrome.
- Gastrin secreting tumour.
List 6 symptoms of GORD.
1 - Heartburn.
2 - Regurgitation.
3 - Dysphagia (swallowing difficulties).
4 - Cough.
5 - Hoarsness (change in voice).
6 - Chronic earache.
List 2 diagnostic methods that can be used to diagnose GORD.
1 - 24 pH monitoring (defines reflux).
2 - Contrast swallow (demonstrates reflux).
List 4 conservative treatments for GORD.
1 - Weight loss.
2 - Avoid food / alcohol close to bed time.
3 - Decrease alcohol.
4 - Raise head of bed 20-30cm.
List 4 medical treatments for GORD.
1 - Proton pump inhibitors (decrease acid).
2 - H2 blockers (decrease acid).
3 - Antacids (increase pH).
4 - Alginates, e.g. Gaviscon (coat mucosa).
List 3 surgical treatments for GORD.
1 - Fundoplication (upper curve of the stomach (the fundus) is wrapped around the oesophagus and sewn in place).
2 - Repair hiatus hernia.
3 - Vagotomy (removal of all or part of the vagus nerve).
What is Barrett’s metaplasia?
A change of epithelial type in the oesophagus in response to environmental stress.
Name a cause of Barrett’s metaplasia.
GORD.
- 10% of GORD patients develop BM.
Name a complication of Barrett’s metaplasia.
Oesophageal adenocarcinoma.
What is an adenocarcinoma?
What is an adenoma?
What is a carcinoma?
- An adenocarcinoma is a malignant adenoma.
- An adenoma is a benign tumour of glandular tissue.
- A carcinoma is a tumour of epithelial tissue.
How does Barrett’s metaplasia change the epithelium lining the oesophagus?
Changes from stratified squamous epithelium to columnar epithelium.
What is achalasia?
- A motor disorder of the oesophagus, causing a loss of myenteric plexus at the lower oesophageal sphincter.
- This causes the lower oesophageal sphincter to relax poorly.
List 4 symptoms of achalasia.
1 - Dysphagia.
2 - Regurgitation.
3 - Chest discomfort.
4 - Halitosis (bad breath).
List 3 treatments for achalasia.
1 - Botox injection at the lower oesophageal sphincter.
2 - Oesophageal dilation.
3 - Surgery (Heller myotomy).
- Muscles of the lower oesophageal sphincter are cut.
What is a pharyngeal pouch?
A posterior defect between the cricopharygeus and the inferior constrictor (Killian’s dehisence).
List 3 symptoms of pharyngeal pouch.
1 - Dysphagia.
2 - Regurgitation.
2 - Halitosis.
List 4 causes of oesophageal rupture.
1 - Endoscopy.
2 - Trauma.
3 - Vomiting.
4 - Boerhaave’s syndrome (a spontaneous perforation of the esophagus that results from a sudden increase in intraesophageal pressure combined with negative intrathoracic pressure).
List 4 symptoms of oesophageal rupture.
1 - Chest pain.
2 - Subcutaneous emphysema (air trapped under the skin).
3 - Sepsis.
4 - Pleural effusion.
What are oesophageal varices?
Extremely dilated sub-mucosal veins in the lower third of the oesophagus
What causes oesophageal varices?
Pre-Hepatic:
- Portal hypertension.
- Portal vein thrombosis.
- External compression of portal vein by tumours.
Post-Hepatic:
- Right heart failure.
- Budd-Chiari syndrome (occlusion of the hepatic veins that drain the liver).
- Also cirrhosis.
List 3 complications of portal hypertension.
1 - Variceal bleeding.
2 - Ascites (accumulation of protein-containing (ascitic) fluid within the abdomen).
3 - Encephalopathy (brain damage).
List 2 medical therapies for oesophageal varices.
What are their effects?
Suggest a surgical therapy.
1 - Beta blockers.
2 - Nitrates.
Both decrease portal pressure.
Liver transplant as a surgical therapy.
