6. Anatomy Of Salivation And Swallowing Flashcards
What is the composition of saliva?
Mostly water.
Is hypotonic compared to blood.
Rich in potassium and bicarbonate (making pH normally slightly alkaline, although can be slightly acidic).
Mucins to help with lubrication.
Amylase.
Lingual lipase (secreted by lingual glands).
Diversity of immune proteins eg IgA, lysozyme, lactoferrin.
Give 3 functions of saliva?
Lubrication for speech.
Moisture to allow eating.
Lysozyme kills bacteria.
Preserves dental health - protects against cavities.
What is xerostomia?
Dry mouth.
What is a patient with xerostomia more susceptible to?
Oral cavities.
Oral thrush and other infections.
Bad breath.
Dysphagia.
What salivary gland is found overlying the masseter muscle?
Parotid gland.
What salivary gland sits above the mylohyoid muscle?
Sublingual gland
What salivary gland sits mostly below the mylohyoid muscle?
Submandibular gland.
What muscle forms the floor of the mouth?
Mylohyoid.
Which salivary glad has multiple ducts that open more laterally into the mouth?
Sublingual gland.
Which salivary gland has one duct that opens medially into the mouth?
Submandibular gland.
Which cranial nerve supplies the submandibular and sublingual salivary glands?
Facial nerve.
Which cranial nerve innervates the parotid salivary gland?
Glossopharyngeal nerve.
What division of the autonomic nervous system is the main driver for salivary secretion?
Parasympathetic.
What affect does the sympathetic nervous system have on salivary secretion?
Stimulates secretion of small amounts of saliva, but also causes vasoconstriction.
Which drugs cause xerostomia as a side effect?
Drugs with antimuscarinic (inhibit ACh production) affects - as inhibits parasympathetics.
Why does mumps cause such severe pain at the parotid gland?
Causes swelling and inflammation inside gland. Gland has dense, thick fibrous capsule which doesn’t stretch, so when inflammation occurs, causes pain.
What type of imaging would you use to check for a stone blocking the parotid duct?
Parotid sialography.
What happens in the oral preparatory phase of swallowing?
This phase is voluntary.
Pushes bolus towards the pharynx.
Once the bolus touches the pharyngeal wall, the pharyngeal phase begins.
What happens in the pharyngeal phase of swallowing?
This phase in involuntary.
The soft palate seals off the nasopharynx.
Pharyngeal constrictors push the bolus downwards.
The larynx elevates, closing the epiglottis.
Vocal cords adduct to protect the airway and breathing temporarily ceases.
The upper oesophageal sphincter opens.
What happens in the oesophageal phase of swallowing?
This phase is involuntary.
The upper oesophageal sphincter closes.
A peristaltic wave carries the bolus downwards into the oesophagus.
How is it possible for a baby to feed and breath at the same time?
Difference in the junction between the epiglottis and the uvula. Epiglottis projects upwards into the nasopharynx, and diverts the milk laterally down towards the oesophagus.
What anatomical change to the location of the epiglottis allows the development of speech in a baby?
As the neck grows and elongates, the epiglottis is pulled downwards, allowing the development of speech.
Describe the neural control of swallowing and the gag reflex
Mechanoreceptors detect the formation of a bolus, glossopharyngeal nerve takes signal to the medulla which contains the control circuit for swallowing. Signal then travels down the vagus nerve to the pharyngeal constrictors which contract and push the bolus inferiorly.
What determines if a person swallows or gags?
Psychological context.
