Salivary Secretions

Question 1

What is lactoferrin?

Answer 1

Iron collator that removes iron from the mouth, which then prevents bacteria growing as they require iron

Question 2

What is Xerostomia?

Answer 2

A condition of which symptoms include a dry mouth and an increased number of cavities, due to a reduced amount of salvia. Usually a system of a condition such as radiation to the head in cancer.

Question 3

What are the 3 major salivary glands?

Answer 3

• Submandibular (70% sero-mucin)
• Parotid (25% serous)
• Sublingual (5% mucin)

Question 4

How much saliva is secretion in a day?

Answer 4

1,500mL/day

Question 5

What is serous?

Answer 5

A watery solution containing high amounts of proteins secreted from serous cells

Question 6

What is mucin?

Answer 6

Glycoproteins that are highly viscous and secreted from mucin cells

Question 7

What are acini?

Answer 7

Clusters of epithelial cells

Question 8

What is a salivon?

Answer 8

Salivary duct, which is a blind end acinus, made up of acinar cells. They secrete primary secretions

Question 9

What are myoepithelial cells?

Answer 9

Cells that surround the epithelial cells, which contain smooth muscle which contract/relax influencing the rate of the secretion

Question 10

What are the main constituents of saliva?

Answer 10

Water, electrolytes and enzymes

• Na+ and Cl- are lower in the saliva than the plasma
• K+ and HCO3- are higher in the saliva than plasma

Question 11

As saliva moves through the ductal system, secondary modification occurs, during the stage, what happens to the ionic composition?

Answer 11

Na+ and Cl- are reabsorbed from the duct

K+ and HCO3- are secreted back into the duct, to a lesser extent that the reabsorption Na+ and Cl-

Question 12

What is expected as ions leave the duct?

Answer 12

Water would follow by osmosis

Question 13

Why is it more more difficult for water to follow ions by osmosis in the ductal system and how is this solved?

Answer 13

Ductal epithelium has a low water permeability making it more difficult for water to follow. So during secondary modification, the solution becomes hypotonic, so has lots of water but a low electrolyte concentration

Question 14

What happens to the composition of saliva at low flow rates?

Answer 14

More time available for reabsorption/secretion, saliva is hypotonic

Question 15

What happens to the composition of salvia at high flow rates?

Answer 15

Less time available for reabsorption/secretion - composition approaches primary secretion, more similar to plasma

Question 16

What nervous is dominant in saliva secretion?

Answer 16

Parasympathetic, the saliva tends to be waterier

Question 17

Mechanism behind parasympathetic control

Answer 17

Parasympathetic control uses the NT ACh acting on the muscarinic receptors, this controls the myoepithelial cells increasing saliva flow rate. VIP is released, which causes vasodilation and increases blood flow and oxygen delivery to the salivary glands, increasing secretion.

Question 18

Mechanism behind sympathetic control

Answer 18

Sympathetic control uses the NT, A and NA acting on adrenoceptors, contract myoepithelial cells to decrease saliva flow rate.

Question 19

What does the cephalic reflex do to saliva production?

Answer 19

The thought of food stimulates the secretion of saliva via the ANS

Question 20

What inputs from the salvia centre increase secretions?

Answer 20

Smell, tactile, chewing and taste

Question 21

What inputs from the saliva centre decrease secretions?

Answer 21

Fear, mental effort and dehydration

Question 22

What is siaolithiasis?

Answer 22

Calcified mass in the salivary gland. Majority cause no symptoms but larger can cause pain and discomfort by interfering with the flow of saliva. Antibiotics and analgesic treatment, siaendoscopy, basket retrieval and salivary lithotrisy

Question 23

What id sialaddenitis?

Answer 23

Infection of the salivary gland, causes by virus/bacteria. Parotid/submandibular gland most commonly affected. Pain, tenderness, swelling.
Treatment include antibiotics, fluid hydration and electrolyte management

Question 24

What is Siogren’s syndrome?

Answer 24

Long term autoimmune disease in which the moisture producing glands of the body are affected. Combination of genetic factors with an environmental trigger, cause unclear. Dry mouth, dry eyes, dry skin and tiredness.

Question 25

Which is the largest of the salivary structures?

Answer 25

Parotid glands - secretes a fairly watery saliva, other 2 secreted a more viscid saliva

Question 26

Where are other small salivary glands located?

Answer 26

Covering the palate, buccal areas, lips and tongue

Question 27

What is the origin of salivary glands?

Answer 27

Ectoderm layer

Question 28

What is the blood supply to the salivary glands?

Answer 28

Distributed by branches for the external carotid artery. The direction of arterial blood flow within the substance of each salivary gland is opposite to the direction of he flowing saliva. Arterioles break up around each acini to form capillaries