Salvia and Glands Flashcards
What are the functions of salvia
Lubricant for mastication, swallowing and speech
Oral hygiene
- wash
- immunity - antibacterial/antiviral/antifungal
- buffer
Digestive enzyme
- aqueous solution necessary for taste
Why does the oral pH need to be maintained at pH 7.2
Bicarbonate/carbonate buffer system for rapid neutralisation of acids
What is the flow rate of salvia
0.3-7mL per minute
What is the daily secretion of saliva
800-1500mL in adults from major and minor glands
What is the role of serous secretion
alpha amylase
starch digestion
What is the role of mucus secretion
Mucins for lubrication of mucosal surface
How does saliva contribute to oral health
Lubrication - mucous coat
Mechanical cleaning - flow
Buffering salts - neutralise acid
Remineralisation - Ca2+ and PO43-
Defensive and digestive function - proteins
How does the defence system work in saliva
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
Does oral mucosa and glands have a high or low blood flow rate
High
What is whole salvia compromised of
Salivary gland secretions
Blood
Oral tissues
Microorganisms
Food remnants
Describe the structure of salivary glands
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
What are intralobular ducts divided into
Intercalated
Striated
Describe intercalated intralobular ducts
Short narrow duct segments with cuboidal cells that connect acini to larger striated ducts
Describe striated ducts
Striated like a thick lawn
Major site for reabsorption of NaCl
Describe the histology of striated ducts
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
What is the composition of primary saliva
NaCl rich isotonic plasma-like fluid secreted by acini
What is the role of the epithelium of the duct
Does not allow any water movement so final saliva becomes hypotonic
What are the three pairs of major salivary glands
What percentage of salivary flow do these equate to
Parotid
Submandibular
Sublingual
80%
What are the minor salivary glands
What % of salivary flow do these equate to
Submucosa of oral mucosa - lips, cheeks, hard and soft palate, tongue
20%
What is the histology of parotid glands
Entirely serous acini with ducts interspersed
Describe the course of the submandibular duct (Wharton’s duct)
Begins in superficial lobe
Wraps round free posterior border of mylohyoid
Runs along the floor of mouth
Empties into oral cavity at sublingual papillae
Describe the histology of submandibular glands
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
Describe the histology of the sublingual gland
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
Where are minor salivary glands found
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)
