Lecture 6 Flashcards
T/F Saliva moderates bacterial growth and facilitates pellicle formation.
True
What is a pellicle?
A protective organic layer formed on the surface layer of enamel
What two minerals are provided by saliva to newly erupted teeth?
Calcium and phosphorus
T/F Saliva is a hypertonic solution of 97-99.5% water.
FALSE. It is a HYPOtonic solution of 97-99.5% water.
What is lingual lipase activated by in the saliva?
Stomach acid
What does lactoferrin do in the saliva?
Chelates iron necessary for bacterial growth
What does IgA antibody do in the saliva?
IgA neutralizes bacteria and viruses
What does SLPI stand for?
Secretory leukocyte protease inhibitor?
Which antibacterial agent in the saliva is thought to be potent against HIV?
SLPI “slippy”
What do histatins do in the oral cavity?
Aid in oral cavity wound healing and have antifungal properties
How much saliva is produced daily?
1 to 1.5 Liters
Food stimulates taste receptors that send signals to which part of the brain, that in turn stimulates saliva?
The medulla and pons of the brainstem
What kind of innervation do salivary glands have?
Autonomic Innervation
Parasympathetic stimulation (rest and digest) of salivary glands produces what kind of saliva?
Thin, serous saliva in large volumes
Sympathetic (nervous or upset) stimulation of salivary glands produces what kind of saliva?
Thicker saliva, with more mucus in small volumes
Why does the Sjogren’s syndrome cause xerostomia?
Lymphocytes invade and destroy glandular epithelium of salivary glands.
What is xerostomia treated with?
Parasympathomimetic drugs like pilocarpine
Most salivary glands are ________ salivary glands.
Minor
Major salivary glands are _______ (intrinsic/extrinsic)
extrinsic
Which type of salivary glands continuously produce small amounts of saliva?
Minor salivary glands
Major salivary glands produce ______ amounts of saliva in response to neural stimulation.
large
About how many minor salivary glands are located throughout the oral cavity?
600-1000
Which parts of the oral cavity do not have minor salivary glands?
Gingiva and anterior hard palate
Most minor salivary glands are ______ (mucous/serous)
mucus
Which minor salivary glands are serous and where are they located?
Ebner’s glands in the tongue that surround circumvallate lamina
What are the three paired major salivary glands?
Parotid, submandibular, and sublingual
What are major glands composed of?
Clusters of glandular acini
How are major glands connected to the oral epithelium?
They are connected to the oral epithelium by a branching system of ducts
T/F Major salivary glands can respond to mechanical or chemical stimulation of sensory nerve endings in the oral mucosa that act through autonomic efferent neurons.
True
Which major salivary gland produces the most volume of saliva?
Submandibular gland produces 70%
What is the name of the submandibular duct?
Wharton’s duct
Which salivary gland is located in the temporal region of the head? What percentage of saliva does it produce?
Parotid gland produces 25%
What is the name of the parotid duct?
Stensen’s duct
Which salivary gland has one major duct and many small ducts that enter individually into the oral cavity? What are the names of these ducts?
Sublingual gland. The main duct is called Bartholin’s duct and the small ones are call rivian ducts or ducts of Rivinus
Which gland produces serous saliva?
Parotid
What kind of enzymes and proteins are in serous saliva?
Enzymes: Amylase, peroxidase, lysozymeProteins: Lactoferrin and IgA
Which gland is mixed, mostly serous-secreting?
Submandibular
Which gland is mixed, mostly mucus producing?
Sublingual
What is an acinus?
A cluster of cells arranged in a sphere with a hollow lumen in the center
What shape are cell of secretory acini?
Polygonal
The central lumen of an acinus first flows in an _______ duct and then into a ________
intercalated; striated
What kind of epithelium are intercalated duct cells?
Simple cuboidal epithelium that may become columnar as it approaches the striated duct
What ind of epithelium can striated duct cells be?
Tall cuboidal or columnar and may be arranged in either a simple or stratified epithelium
Serous cells are ________ shaped with a ______ basal end and a _______ apical end.
Pyramidal; broad; narrow
Serous cells have a well developed rough ________ reticulum
endoplasmic
Secretory granules produced by serous cells are located in which part of the cytoplasm?
Apical region near the lumen
Why does the nucleus of mucous cells tend to be pressed up against the basal surface?
Because it is crowded by so many mucus vesicles.
What kinds of cells surround the periphery of the acinus?
Myoepithelial cells
Does the mucous acinus readily stain under most routine histologic preparations
No it is very difficult to stain and therefore it appears paler than serous acinus
What shape do serous cells take on after being histologically fixed and processed?
Demilune or half-moon
Why do serous cells become demilune?
Adjacent mucous cells swell and force the serous cells out
Myoepithelial cells are similar to what type of muscle? Where are they derived from?
Similar to smooth muscle but are derived from epithelia (muscle is usually derived from mesoderm)
What mechanical role do myoepithelial cells play within acini?
Weakly contractile, they help to expel saliva from acini and shorten and widen the intercalated ducts
What chemical role do myoepithelial cells play within acini?
They produce signal molecules necessary for maintaining acinar cell polarity
What is a salivon?
The basic secretory unit of salivary glands
What are the four major parts of a salivon?
AcinusIntercalated ductStriated ductExcretory duct
Where is primary saliva formed?
The acinus and intercalated ducts
What kind of concentration does primary saliva possess?
Isotonic
What kind of concentration does final saliva possess?
Hypotonic
How does final saliva become hypotonic?
Mainly by reabsorption of Na+ and Cl- ions as it passes through the striated and excretory ducts
By what mechanism do organic components of saliva get outside of the saliva producing cells and into the acinus?
Exocytosis through the apical membrane
What neurotransmitter/hormone mediates the exocytosis of secretory cells? By which branch of autonomic innervation is it mediated?
Mediated by norepinephrine from sympathetic innervation through beta-adrenergic receptors
How is water and electrolyte secretion mediated in the formation of saliva?
It is mediated through acetylcholine from parasympathetic innervation.
What receptors does acetycholine bind to to activate transport of electrolytes with water?
Muscarinic cholinergic and alpha-adrenergic receptors.
What transmembrane structures do electrolytes with water pass through?
Aquaporin and tight junctions
What is the role of salivary gland epithelial cells in getting IgA into the acinus lumen?
Salivary gland epithelial cells secrete a glycoprotein secretory component that binds IgA. Bound IgA is internalized and carried through the epithelia cell to the apical plasma membrane and released into the lumen
Where is Salivary IgA synthesized?
In plasma cells in the CT around the secretory acini
How is bound IgA internalized into the epithelial cells?
By receptor-mediated endocytosis
Myoepithelial cells are found on what two parts of the salivon?
Acini and intercalated ducts
Which salivary duct adds lysozymes and lactoferrin?
Intercalated duct
The intercalated duct is simple ________ epithelium.
cuboidal
How does the striated duct make the saliva hypotonic?
By reabsorbing Na+ and Cl- from primary secretions
What does the striated duct secrete into the saliva?
Buffering bicarbonate (HCO3-)
Which duct connects the salivon directly to the oral cavity?
Excretory duct
The excretory duct may been as a simple ______ epithelium that transitions to simple ______ and often to peusostratified or ________ columnar epithelium near the opening of the duct
cuboidal; columnar; stratified
Why would fast production of saliva be more salty?
If saliva moves too fast through the saliva, then it will not have enough time for the ducts to remove salts
