Lecture 8: Saliva

Question 1

What are the three main functions of saliva?

Answer 1

• lubrication: due to mucus content, facilitates swallowing and speaking
• protection: against hot drinks, being sick, washes away debris in our teeth, antibacterial: lysozymes/lactoferrin
• digestion: contains salivary amylase, lingual lipase

Question 2

What is the function of lactoferrin?

Answer 2

Collates iron

- some bacteria require iron to multiply, so this reduces iron availability

Question 3

What are the 3 main salivary glands?

Answer 3

• paired parotid glands (25% of saliva, serous, lots of enzymes), lying in front of the ear, and below the zygomatic arch, masseter muscle is anterior, inferior border is the mandible
• paired sublingual glands(5% of saliva, mucous, less enzymes), lie underneath tongue
• submandibular gland (70% of saliva, mixed serous and mucous), lies underneath the mandible

Question 4

What type of glands are salivary glands?

Answer 4

Exocrine

-duct which leads into an epithelial lined structure (mouth)

Question 5

Where is the initial saliva produced?

Answer 5

• acinar cells in the acinus (berry shape)
• myoepithelial cells to contract acinar cells and saliva out
• saliva here is isotonic with plasma
• once the saliva enters the ductal cell region, these cells contain transporters which move sodium and chloride ions out of the solution, and the ducts are relatively impermeable to water, producing a hypotonic solution= DUCTAL MODIFICATION

Question 6

What ions are secreted out from the ductal cells into the saliva?

Answer 6

-K+
-HCO3-
But this secretion, is less than the amount of sodium/chloride removed, so we still end with a hypotonic solution

Question 7

When do we produce the most hypotonic solution of saliva?

Answer 7

At rest
-low flow rate
-increased contact time with ductal cells
(whereas when we eat we produce saliva quickly, so there is a high flow rate, less contact time with the ductal cells, least modification)

Question 8

What ion is secreted more at high flow rates?

Answer 8

HCO3-

-more secreted during active saliva production

Question 9

What is the nerve supply to the salivary glands?

Answer 9

Autonomic control, parasympathetic and sympathetic
Sympathetic: blood vessel constriction, saliva produced is less watery
Parasympathetic: via glossopharyngeal nerve to parotid gland, and branches of the facial nerve for the submandibular and sublingual glands

Question 10

What is xerostomia?

Answer 10

Not enough saliva produced, which can lead to infections, tooth decay, halitosis (chronic bad breath)
Causes:
-medication
-autoimmune
-demetia
-radiotherapy
-dehydration

Question 11

What are some infections associated with the salivary glands?

Answer 11

Viral: mumps (parotid gland),

Question 12

What are some autoimmune conditions associated with the salivary glands?

Answer 12

Sjogrens: dry mouth, swollen and painful salivary glands

Question 13

What are sialoliths?

Answer 13

Salivary stones, calcified

• occur in glands, but more likely in the ducts
• submandibular gland is most commonly affected, joins to the mouth via Whartons Duct
• so there is pain when you try and produce saliva