Salvia and Glands

Question 1

What are the functions of salvia

Answer 1

Lubricant for mastication, swallowing and speech

Oral hygiene
- wash
- immunity - antibacterial/antiviral/antifungal
- buffer

Digestive enzyme
- aqueous solution necessary for taste

Question 2

Why does the oral pH need to be maintained at pH 7.2

Answer 2

Bicarbonate/carbonate buffer system for rapid neutralisation of acids

Question 3

What is the flow rate of salvia

Answer 3

0.3-7mL per minute

Question 4

What is the daily secretion of saliva

Answer 4

800-1500mL in adults from major and minor glands

Question 5

What is the role of serous secretion

Answer 5

alpha amylase

starch digestion

Question 6

What is the role of mucus secretion

Answer 6

Mucins for lubrication of mucosal surface

Question 7

How does saliva contribute to oral health

Answer 7

Lubrication - mucous coat

Mechanical cleaning - flow

Buffering salts - neutralise acid

Remineralisation - Ca2+ and PO43-

Defensive and digestive function - proteins

Question 8

How does the defence system work in saliva

Answer 8

Mucosa - physical barrier

Palatine tonsils - lymphocytes subsets and dendritic cells - immune surveillance and resistance to infection

Salivary glands - saliva washes away food particles bacteria or viruses might use for metabolic support

Question 9

Does oral mucosa and glands have a high or low blood flow rate

Answer 9

High

Question 10

What is whole salvia compromised of

Answer 10

Salivary gland secretions

Blood

Oral tissues

Microorganisms

Food remnants

Question 11

Describe the structure of salivary glands

Answer 11

Composed of two morphologically and distinct epithelial tissue

Acinar cells around
Ducts - collect to form large duct entering the mouth

Equipped with channels and transporters in the apical and basolateral membranes enabling transport of fluid and electrolytes

Question 12

What are intralobular ducts divided into

Answer 12

Intercalated

Striated

Question 13

Describe intercalated intralobular ducts

Answer 13

Short narrow duct segments with cuboidal cells that connect acini to larger striated ducts

Question 14

Describe striated ducts

Answer 14

Striated like a thick lawn

Major site for reabsorption of NaCl

Question 15

Describe the histology of striated ducts

Answer 15

Appear straited at the basal end

Basal membrane is highly folded into microvilli for active transport of HCO3 against the concentration gradient

Microvilli filled with mitochondria for energy to facilitate active transport

Question 16

What is the composition of primary saliva

Answer 16

NaCl rich isotonic plasma-like fluid secreted by acini

Question 17

What is the role of the epithelium of the duct

Answer 17

Does not allow any water movement so final saliva becomes hypotonic

Question 18

What are the three pairs of major salivary glands

What percentage of salivary flow do these equate to

Answer 18

Parotid
Submandibular
Sublingual

80%

Question 19

What are the minor salivary glands

What % of salivary flow do these equate to

Answer 19

Submucosa of oral mucosa - lips, cheeks, hard and soft palate, tongue

20%

Question 20

What is the histology of parotid glands

Answer 20

Entirely serous acini with ducts interspersed

Question 21

Describe the course of the submandibular duct (Wharton’s duct)

Answer 21

Begins in superficial lobe

Wraps round free posterior border of mylohyoid

Runs along the floor of mouth

Empties into oral cavity at sublingual papillae

Question 22

Describe the histology of submandibular glands

Answer 22

Mixed gland with some serous and mucous acini

Some serous acini arranged as a crescent-shaped groups of glandular cells at the bases of mucous acini referred to as serous demilunes

Question 23

Describe the histology of the sublingual gland

Answer 23

Variable size with mixed acini - mainly mucous

No large duct - drains into submandibular

(Wharton’s) duct and/or small ducts that pierce oral mucosa on the floor of the mouth

Question 24

Where are minor salivary glands found

Answer 24

Concentrated in buccal labial, palatal and lingual regions

Also found at-
- superior pole of tonsils (Weber’s glands)
- tonsillar pillars
- base of tongue (von Ebner’s glands - underlying circumvallate papillae)

Question 25

What is the histology of minor salivary glands

Answer 25

All mucous expect serous glands of von Ebner

Lack a branching network of draining ducts - each salivary unit has own simple duct