Lecture 6- Swallowing and saliva Flashcards
Function of saliva
lubrication
protection
digestion
lubrication
- Mucus content
- Essential for swallowing
- Good for speech
protection
- Protection from hot drinks and food
- Cools it down
- When we are about to be sick we will saliva to protect against acidic environments
- Good for our teeth
- Buffers acid
- Washes away debris stuck in teeth
- Antibacterial
antibacterial qualities of saliave
- Lysozymes
- Lactoferrin- reduces iron availability for bacteria
- IgA
- Digestion
- Salivary amylase- carbs
- Goes down into stomach and the food buffers the acidic stomach long enough for it to cause some digestion in the stomach
- Lingual lipase- fat digestion
- Can survive acidic environment of stomach and proximal part of the small intestine
3 main salivary glands
parotid
sublingual
submandibular
parotid gland location
paired x2)
- in front of the ear
- Below the zygomatic arch
- posterior to masseter muscle
- inferior border is the inferior border of the mandible
sublingual location
lie under hte tongue
submandibular
sits below the mandible
type of slavia produced by parotid gland
serous with lots of enzymes
type of saliva produce by submandibular
- produces the most saliva (70%)
- Produces a mixed saliva
- Serous
- Mucous
type of saliva produced by sublingual
mucous (produces the least)
which gland contributes the most saliva
submandibular (70%)
which gland produces the least saliva
sublingual (5%)
parotid produces how much of the total saliva
255
exocrine structure of salivary gland
- Acinus is where the salvia is produced
- ductal region where the saliva is made more hyotonic
describe how saliva is produced
- Acinus is where the saliva is produced
- Isotonic with plasma
- Isotonic solution passes out of the acinus due to myoacinus epithelial cells which contract the acinus to move saliva into the duct
- Once in the ductal region , ductal cells use transporters to move Na+ and Cl- out of the solution and K+ and HCO3- into the solution
- Producing a hypotonic solution near the end of the duct (removal of ions >secretion)
The amount of modification (more or less hypotonic)by the ductal cells depends on how quickly the saliva is moving through the ductal system
- Basal level- most hypotonic solution
- When eating the solution moves through much quicker, less contact with ductal cells- smallest change to the tonicity of the isotonic solution (more secretion of HCO3- when active saliva production
What is secreted into the ductal lumen of the salivary gland and what is absorbed by the ductal cells
sodium and chloride are absorbed from the isotonic saliva produced in the acinus
K+ and HCO3- is secreted into the saliva before it leaves the duct
MORE HYPOTONIC SOLUTION
Nerve supply to salivary glands
*
- Completely autonomic
- Parasympathetic and sympathetic control
- Sympathetic control of salivary glands
Less watery (why we get a dry mouth in the ‘fight and flight’ as opposed to ‘rest and digest’
- Parasympathetic control of salivary glands
- Glossopharyngeal – parotid
- Facial nerve
- Submandibular and sublingual
disease of the salivary gland
xerostomia= not enough saliva
xerostomia= not enough saliva causes
- Medications
- Autoimmune
- Sjogren’s syndrome (dry, swollen and painful salivary glands)
- Dementia
- Radiotherapy
- Dehydration
signs and symptoms of xerostomia
-
Infections
- Viral- mumps
- Bacterial
- Tooth decay
- Halitosis (bad breath)
-
Salivary stones
- ‘Sialoliths’- calcified
- Most common location= submandibular gland which is attached to the mouth by Wharton’s duct can be very painful when producing saliva e.g. before you eat
3 phases of swallowing
oral phase
pharyngeal phase
oesophageal phase
outline the oral phase
Voluntary
- 2 stages:
- Preparing the bolus
- Chewing
- Move bolus to oropharynx
- We use the tongue to move the olus up against the hard palate and then slowly move it backwards towards the oropharynx
- As soon as the bolus touches the oropharynx a reflex sets in which moves swallowing into the pharyngeal phase
2. Pharyngeal phase
- INVOLUTNARY- reflex
- Takes place in less than 1 second (0.2 seconds)
- Soft palate raises up and seals off the nasopharynx
- Pharyngeal constrictors start to push the bolus downwards
- Larynx elevates which closes the epiglottis- stops aspiration
-
Vocal cords adduct further protection of airway
- Breathes ceases
- Upper oesophageal sphincter relaxes and opens
3. Oesophageal phase
- INVOLUNTARY
- Closure of upper oesophageal sphincter to stop air in GI tract
- Rapid peristalsis in oesophagus
Difficulty in swallowing
- Dysphagia
dysphagia can be caused by
If there is any problems in coordinating swallowing
Physical blockage to passe of food
If there is any problems in coordinating swallowing:
- Ineffective swallow
- Dribble
- Material entering resp tract
- Coughing
- Choking
- Pneumonia
Any disease process which may disturb the nerves supplying the upper GI tract may affect swallowing
- Stroke
- Parkinson’s
- Multiple sclerosis
Swallowing fluids is harder than solids
Need tighter control since can go in all directions
Use thickener
2) Physical blockage to passe of food
- Fluid easier to passes easier than food
-
Causes
- Fibrous rings- repeated scaring from reflux
- Oesophageal cancer
- Progressive dysphagia as the mass grows
- (red flag)
- Achalasia (lower oesophageal sphincter failures to relax)
