Anatomy Of Salivation + Swallowing Flashcards
Functions of saliva
- lubrication
- maintenance of oral hygiene
- early stages of digestion
- protection from infection
- taste
- (transmission of infection)
What is the composition of saliva?
- mostly water
- hypotonic
- rich in potassium + bicarbonate
- mucin: helps with lubrication
- amylase
- lingual lipase
- immune proteins e.g. IgA, lysozyme, lactoferrin
Where is amylase secreted form?
Salivary glands
Where is lingual lipase secreted from?
Lingual glands
What is xerostomia?
Dry mouth
What are the teeth from front to back?
- central incisor
- lateral incisor
- canine
- first + second premolar
- first, second + third(wisdom) molar
What is the maximum number of teeth an adult can have?
32
(28 + 4 wisdom teeth)
What is the inner surface on the gum called?
Lingual surface of gum
What is the outer surface of the gum called?
Buccle surface of gum
What type of glands are salivary glands?
Exocrine gland
Where does the parotid gland enter the mouth?
Penetrate buccinator opposite 2nd upper molar tooth
What are the types of salivary glands?
- parotid
- sublingual
- submandibular
Where is the sublingual gland?
Below the tongue
Where is the submandibular gland?
Below the mandible
Why do you get a dry mouth when youre anxious?
Sympathetic nervous system causes vasoconstriction of vessels > decreases of saliva
How do you image the salivary glands?
Sialography
What are the phases of swallowing?
Oral preparatory phase
Pharyngeal phase
Oesophageal phase
Define bolus
Food in mouth ready to be swallowed
Outline the oral preparatory phase
- voluntary
- pushes bolus towards pharynx (back of mouth)
- once bolus touches pharyngeal wall, pharyngeal phase begins
When does the pharyngeal phase of swallowing begin?
Once bolus touches pharyngeal wall
Outline the pharyngeal phase
- involuntary
- soft palate seals off nasopharynx
- pharyngeal constrictors push bolus down
- larynx elevates + closes epiglottis
- vocal cords adduct + breathing stops temporarily
- opening of upper oesophageal sphincter
Outline the oesophageal phase
- involuntary
- closure of upper oesophageal sphincter
- peristaltic waves moves bolus down
Outline the neural control of swallowing + gag reflex
Mechanoreceptors => innervated by glossopharyngeal nerve => medulla => vagus nerve => pharyngeal constrictors
What is the sensory component of the swallow reflex?
Glossopharyngeal nerve
What nerve innervates most of the muscles in the swallow reflex?
Vagus nerve
What is dysphagia?
Difficulty swallowing
Where are there narrowings in the oesophagus?
- junction of oesophagus with pharynx
- crossed by arch of aorta
- compressed by left main bronchus
- passes through diaphragm
What prevents gastro-oesophageal reflux?
- mucosal rosette
- acute angle of entry of oesophagus
- lower oesophageal sphincter
What is barrett oesophagus?
- Reversible change (metaplasia) of stratified squamous epithelia into gastric columnar
- due to repeated exposure of gastric contents
. - risk of adenocarcinoma due to increased risk of dysplasia
What is the tonicity of salvia at average flow rates?
Hypotonic
How does the tonicity of saliva change as flow rates increase and why?
- at higher flow rates, saliva becomes less hypotonic
- as the flow rate increases the contact time with initially isotonic solution is less > less modification of the composition (removal of Na+ and Cl-) occurs
What happens to the conc. of bicarbonate ions at higher flow rates of salvia?
Increases
(unlike others)
Location of the parotid gland
- in front of ear
- below zygomatic arch
- massester muscle is anterior
- lower border: inferior border of mandible
How much saliva is produced by each gland?
Submandibular 70%
Parotid 25%
Sublingual 5%
Composition of saliva from the parotid gland
How does this affect staining?
Serous
Lots of enzymes
25% of saliva
Darker
Composition of saliva from the sublingual gland
How does this affect staining?
Mucous
Less enzyme
5% of saliva
Lighter staining
Composition of saliva from the submandibular gland
How does this affect staining?
Serous + mucous
Mix of dark + light staining
What is the tonicity of intial saliva?
Isotonic
When is saliva the most hypotonic?
At rest/low flow rates
Increased contact time with ductal cells
Nerve supply to the salivary glands
Glossopharyngeal nerve - parotid
Facial nerve - sublingual + submandibular
What is mumps?
Viral infection of the parotid glands
What is Sjögren’s syndrome?
Autoimmune disease of the salivary glands
What is sialoliths?
Calcified salivary stones
Most commonly in the submandibular gland
Is it harder to swallow fluids or solids if a patient has problems with coordination swallowing?
Harder to swallow fluids
Is it harder to swallow fluids or solids if a patient has a blockage?
Harder to swallow solids
Liquids can pass around the blockage
Causes of dysphasia due to problems coordinating swallowing
- cerebrovascular accident
- stroke
- Parkinson’s disease
- multiple sclerosis
Cause of dysphagia due to a blockage
- fibrous rings
- oesophageal cancer
- achalasia
What is achalasia?
Failure of lower oesophageal sphincter to relax
Difference in mucous + serous cell staining
Mucous - lighter
Serous - darker (more proteins)
What salivary gland is most commonly affected with stones and why?
Submandibular gland
Higher conc. of calcium in saliva
