6 Salivation and Swallowing Flashcards
What are the components that make up saliva?
- Water (mostly) (hypotonic)
- Potassium and bicarbonate (pH alkaline-protect teeth)
- Mucins (make up mucus) (glycoproteins)
- Amylase
- Lingual lipase (secreted by lingual glands)
- Immune proteins (IgA, lysozyme, lactoferrin)
- Lactoferrin- sequesters iron- helps prevent infection
What are the functions of saliva?
- Hydrate food- form bolus
- Moisten mouth- enable us to speak
- Solvent- dissolve flavour molecules
- Begin process of digestion
- Prevent infection
What is xerostomia?
Dry mouth- insufficient saliva production
Name some consequences (symptomatic) of having xerostomia.
- Loss of all functions of saliva (see flashcard 2)
- Dental cavities
- Bad breath- overgrowth of bacteria
- Ulcers- mucosa not moist
What are some causes of xerostomia?
- Side effect of drugs eg antidepressants
- Blocked nose- breathing through mouth
- Radiotherapy to head
- Salivary gland removal
- ANYTHING REDUCING PARASYMPATHETIC INNERVATION
Label glands 1-3:
How would you clinically examine the sublingual glands?
Compress finger and thumb- in mouth and under chin
What muscle does the parotid duct pierce through?
Buccinator
Where do the sublingual and submandibular ducts open in the floor of the mouth? (lateral or medial)
- Sublingual: laterally
- Submandibular: medially
How is salivary secretion regulated?
Autonomic (primarily)
- Parasympathetic (main driver)
- Stimulate salivary
- Sympathetic
- Stimulate small amount of secretion
- BUT cause vasoconstriction if too well stimulated
Which nerves supply the salivary glands with parasympathetic input?
- 9th Cranial: Glossopharyngeal nerve
- Parotids
- 7th Cranial: Facial nerve
- Sublingual and submandibular
What is the diagnosis? Why is this condition so painful?
Mumps- inflamed parotid glands
Painful: Parotid gland has tight capsule surrounding it
Capsule innervated by trigeminal- sensory innervation- very sensitive to stretch
What is parotid sialography?
(Sialo=salivary glands)
Contrast study to parotid gland
What symptoms might be caused by stones in the parotid gland/duct?
Pain on eating/anticipating eating/swelling of parotid gland on anticipation of eating
Name the 3 phases of swallowing:
- Oral preparatory phase
- Pharyngeal phase
- Oesophageal phase
Become less voluntary
Describe the first phase of swallowing (oral preparatory). (3)
- Voluntary
- Pushes bolus down towards pharynx
- Phase ends once bolus touches pharyngeal wall (initiates swallowing reflex)
- Hypoglossal nerve XII- muscles of tongue
Describe the second phase of swallowing (pharyngeal). (7)
- Involuntary
- Soft palette elevates, seals off nasopharynx
- Pharyngeal sphincters push bolus down
- Larynx elevates (suprahyoids), closes epiglottis and moves anteriorly, to open oesophagus
- Vocal cords adduct- protect airway
- Phrenic nerve switches off- temporarily cease breathing
- Open upper oesophageal sphincter
Tongue against hard palate- food can’t reenter mouth
Involves CNs V3, VII, IX, X, XII
Describe the third phase of swallowing (oesophageal). ()
- Involuntary
- Closure of upper oesophageal sphincter
- Peristaltic wave carries bolus downwards into oesophagus
How is swallowing controlled neurally? (reflex arc) (5)
- Mechanoreceptors in pharygeal wall- detect presence of bolus
- Glossopharyngeal nerve
- Medulla
- Vagus nerve
- Pharyngeal constrictors
At what age does the hyperactive gag reflex begin to be inhibited (baby can be given food) ?
6 months
What is dysphagia?
Difficulty swallowing
What is important to remember when looking after stroke patients with regards to their swallowing?
May have dysphagia (difficulty swallowing)
Need to check that it is safe before giving water/food
May need to be nil by mouth
If given water- enters trachea may cause pneumonia
What is shown here in the oesophagus? How might this patient present?
Presentation:
Solid food will stick in oesophagus
Drink will pass fine
At what points does the oesophagus narrow? (4)
- Junction of esophagus with pharynx
- Where esophagus crossed by arch of aorta
- Where esophagus compressed by left main bronchus
- At esophageal hiatus (piercing diaphragm)
What is the first line of treatment for a bolus stuck at the junction of the esophagus and the pharynx?
Drug designed to relax wall of oesophagus
(Then esophagoscapy)
What structures in the GI tract prevent gastro-oesophageal reflux?
- Lower oseophageal sphincter (muscle contraction is due to diaphragm)
- Flap valve formed due to oesophagus entering stomach at oblique angle
