6 - Salivation Flashcards
What are the main components of saliva?
- Water
- IgA
- Lysozymes
- Lactoferrin (stop bacteria getting iron so stops infection)
- Amylase
- Lingual lipase (from lingual glands)
- Kellirein (enzyme to make bradykinin)
- K+ and Bicarbonate so slightly alkaline
- Mucins (lubrication)
Is saliva hyper/hypo/isotonic?
When it is first made it is isotonic to plasma the becomes hypotonic in the duct. How hypotonic depends on the flow rate
What are some of the functions of saliva?
- Initiate digestion
- Maintain oral hygeine from infections
- Solvent for flavour
- Speak
- Hydrate food to make bolus
- Help to speak by lubricating
What is xerostomia, why may it occur and what issues can it cause?
- Reduced flow of saliva in the oral cavity.
- Could be due to drug side effects, e.g antidepressants, mouth breathing, salivary gland removal
- May lead to dental cavities, ulcers, halitosis
Where are the three pairs of salivary glands?
What is the neural control of the salivary glands?
- Autonomic (mainly parasympathetic)
- Low levels of parasympathetic means little salivation and dry mouth
- High levels of sympathetic causes vasoconstriction and off
What is this diagnosis, why is it painful and how would you investigate the function of the gland involved?
- Mumps
- Stretched capsule which is innervated by trigeminal nerve and when stretched feel the pain
What would a patient with a parotid gland blockage by a calcification present with?
- Pain and swelling particularly on eating
- May feel bit of gristle and pain goes as stone comes out
What are the phases of swallowing and what occurs in each?
- Oral: voluntary, bolus pushed back on pharyngeal wall and when it touches pharyngeal phase starts
- Pharyngeal: involuntary, bolus moved from oral cavity to beginning of oesophagus. Soft palate seals off nasopharynx. Pharyngeal constrictors push bolus down. Larynx elevates by suprahyoids, closing epiglottis. Vocal cords adduct and upper oesophageal sphincter opens
- Oesophageal: Involuntary, closure of upper oesophageal sphincter to stop reflux, rapid peristaltic wave carries bolus into stomach
What are the main changes as you go down the oesophagus in swallowing?
- Less voluntary
- Skeletal to smooth muscle
How does the body protect the airway and nasal cavity during swallowing?
- Nasal cavity: soft palate elevates
- Respiratory: adduction of vocal cords and larynx elevation to close epiglottis
How does a baby swallow and breath at the same time?
- Short necks so their epiglottis is as far up as the nasopharynx. Epiglottis acts as a divider for milk to go around so can do both.
- Can’t speak when like this. As babys neck grows the epiglottis moves down
- Obligate nose breathing
What nerves are involved in the gag and swallow reflex?
If a patient is suffering with dysphagia due to issues with their upper oesophagus, what can they usually not take in?
- Liquids as they tend to aspirate it
- Need to check if stroke patient can swallow as their pharyngeal constrictor muscles will be damaged along with their facial muscles
If there is an obstruction in the lower oesophagus, e.g a malignancy, what may a patient complain of?
- Difficulty swallowing solids, not liquids
- Dysphagia can be neural or physically obstructive
Where are the narrowings in the oesophagus and what are the importance of these locations?
Bolus can get stuck in these locations
How is gastro-oesophageal reflux prevented?
- Oesophagus enters the stomach at an oblique angle forming a flap valve so when pressure rises in stomach this valve closes.
- Also diaphragm acts as a sphincter as well as smooth muscle forming lower oesophageal sphincter
- Mucosal rosette at cardia
What is gastrooesophageal reflux disease and what can it lead to?
- Lower oesophageal sphincter fails.
- Heartburn and can lead to metaplasia and Barrett’s oesophagus
Which salivary gland forms the most saliva?
Submandibular
How is saliva synthesised in its gland?
- High flow rate less ion exchange apart from HCO3- which is secreted more
- Saliva high in K, HCO3,
- Na and Cl removed
- Na/K ATPase and Cl pump on opposite side of ductal cell
What are some clinical signs in a patient with poor saliva production and what broad class of drugs can decrease saliva production?
- Halitosis
- Xerostomia
- Thrush
- Ulcers and Infections
- Anticholinergics and SSRIs: inhibit parasympathetics
What phase of swallowing is there a risk of aspiration?
Pharyngeal - stopped by vocal cords adducting and superior hyoid lifting larynx up and loses epiglottis
This man reports lethargy, why may this be?
- Reduced calorific intake
- Tumour burden
How is gastrin release stimulated and what effects does it have once released?
- Vagus nerve releases Ach causing GRP to be released and presence of peptides
- Both cause gastrin to be released from G cells
- Stimulates pepsinogen release from chief cells and HCl release from parietal
How is gastric acid secretion inhibited?
- Somatostatin
- Low pH of stomach
- Reduced distension of stomach so loss of vagal stimulation
Where is pain from a peptic ulcer referred to and why?
- Foregut structure so innervated by greater splanchnic nerve T5-T9
- Visceral pain so reffered to epigastric area
What medication can be used to treat peptic ulcer disease?
- PPI
- H2 anatagonists
- Protectants: coat ulcer to protect from enzymes and acids so has time to heal
What are the stages of fat absorption?
