GI 3 - Salivation + Swallowing Flashcards
What are the functions of saliva?
- Protects oral cavity (keeps mucosa wet and neutralises bacterial acid)
- Moistens and lubricates food
- Begins digestion (enzymes)
- Solvent for taste molecules
- Can be involved in the transfer of disease
- Allows structures to pass over each other smoothly, for phonation
Approx. how much saliva do we produce per day?
1.5 L
What percentage of total saliva production is produced by each gland?
~ 70% Submandibular gland
~ 25% Parotid gland
~ 5% Sublingual gland
Name the 3 salivary glands:
1) Submandibular gland
2) Sublingual gland
3) Parotid gland
Do the salivary glands secrete serous or mucous fluids?
Parotid = serous Submandibular = seous + mucous Sublingual = mucous
List the constituents of saliva:
- Water
- Mucins
- Alpha-Amylase
- Lingual lipase
- Electrolytes
- Kallikrein
- Immune proteins (IgA, Lyzozyme, Lactoferrin)
Name the 2 cell types responsible for saliva production:
- Acinar cells
- Ductal cells
When saliva leaves the acinus into the duct of the gland, is it hypotonic, isotonic, or hypertonic to plasma?
ISOTONIC
When saliva leaves the duct of the salivary gland, is it hypotonic, isotonic or hypertonic to plasma? Why?
HYPOTONIC
- Ductal cells remove Na+ and Cl- from saliva
- Tight junctions between ductal cells prevent movement of water
= Less ions = hypotonic
Saliva contains Kallikrein. How does this protease increase the blood flow to the salivary glands?
It produces bradykinin, which causes vasodilation allowing an increase in blood flow
How does saliva change at high flow rates (when stimulated by parasympathetic fibres)?
- Becomes more isotonic
- More alkaline
- Higher enzyme content
The parasympathetic fibres to the salivary glands hitch-hike on cranial nerves to reach their destination. Which cranial nerves are involved?
Submandibular + Sublingual = CN VII (Chorda Tympani)
Parotid = CN IX Glossopharyngeal
Are the salivary glands stimulated by parasympathetic or sympathetic fibres?
Parasympathetic fibres
How can otitis media lead to a dry mouth?
- Otitis media may damage Chorda tympani nerve which runs through the middle ear.
- Chorda tympani contains the parasympathetic nerve fibres which stimulate the submandibular and sublingual salivary glands
What is xerostomia? What can it be caused by?
Dry mouth
- Medications - antidepressants, antihistamines
- Anxiety
- Chemo- + Radiotherapy
- Sjogrens autoimmune disease
- Dehydration