Anatony Of Salivation And Swallowing Flashcards
What is the composition of saliva
- Mostly water
- Hypotonic (depending on flow rate)
- Rich in potassium and bicarbonate (pH slightly acidic to ~8)
- Mucins help with lubrication
- Amylase (secreted by salivary glands) • Lingual lipase (secreted by lingual glands)
- Contains a diversity of immune proteins (e.g. IgA, lysozyme, lactoferrin)
- See Mark Hamilton’s video for more detail on saliva production
What are some functions of saliva
Lubricaion of oral cavity
Surface tension eg keeping dentures in
Moisten dry foods, make food easier to make into a bonus
Immune proteins - lysozymes - Jimmunen properties
Versatile solvent. Foods have different properties - presents different food molecules to different receptors
Saliva - a root whereby infections can spread -
Rabies virus gets to brain and make rabid animals wasn’t to bite others to spread it
What is xerostomia
Dry mouth
Oral hygiene?
Sell function of saliva
Dryness of mouth leads to inflammation of tongue - redness, swelling, soreness
Bad breath. Bc no saliva minimising growth of bacteria
Describe the basic topography of the salivary glands
Largest salivary gland is parotid ground under ear
Duct of the parotid gland comes past biccinator nad opposite top second molar - mucosal flappy on inner surface of cheek
Sublingual gland, sit above mylohyoid,
Submandibular gland just in front of angle of mandible. -
Submandibular duct drains just off the midline
Sublingual has multiple ducts that drain more laterally than submandibular
Calcium salts can form stones in the salivary glands, can lead to pain, transientt swelling of the salivary gland,
Describe teh neural control of salivary glands
Complex regulation of salivary secretion:
• Primarily neural (autonomic)
• Parasympathetic is main driver (increases production)
• Sympathetic also stimulates secretion of small amounts of saliva, but also causes vasoconstriction
• Which drugs might have dry
mouth as a side effect?
Parotid - glossopharyngeal nerve
Sublingual and submandibular - facial nerve
Give an overview of swallowing
• Oral preparatory phase (0-7.4) • Voluntary • Pushes bolus towards pharynx • Once bolus touches pharyngeal wall, pharyngeal phase begins
• Pharyngeal phase (7.4-7.6)
• Involuntary
• Soft palate seals off nasopharynx - so bits of food not up in nasal cavity
• Pharyngeal constrictors (muscular walls of pharynx) push bolus
downwards
• Larynx elevates, closing epiglottis
• Vocal cords adduct (protecting airway) and breathing temporarily ceases
• Opening of the upper oesophageal sphincter
• Oesophageal phase (7.6 onwards) • Involuntary • Closure of the upper oesophageal sphincter • Peristaltic wave carries bolus downwards into oesophagus
How do babies swallow
Babies are neurologically immature
Swallowing frflex imamture - risk of aspiration
Not as issue if breast milk is aspirated
Nasopharanxy up - milk goes around epiglottis - directs amount it into oesophagus. Epiglottis acts as a diversion
Cannot speak with epiglottis up in nasopharynx,.
Larynx descends when babies start to make more noises
This is a safe system
Scribe the neural control of swallowing and the gag reflex
Mechanoreceptors Glossopharyngeal nerve Medulla Vagus nerve Pharyngeal constrictors
Problems with any of these structures can les to problems with swallowing reflexswallow
What are the 4 narrowings of the oesophagus
Most of oesophagus is in the thorax,some in abdomen and neck,
4 major narrowing
1) junction of oesophagus with pharynx - sphincter
2) where oesophagus is crossed by arch of the aorta
3) where oesophagus is compressed by left main bronchus
4) at the oesophageal hiatus (passes diaphragm @ T10)
Also heart can compress oesophagus - can lead to dysphasia - left atrium can directly compress it
How is gastro oesophageal reflux prevented
- Functional sphincter formed from smooth muscle of distal oesophagus
- Diaphragm
- Intra-abdominal oesophagus which gets compressed when intra- abdominal pressure rises
- Mucosal ‘rosette’ at cardia
- Acute angle of entry of oesophagus
