salivary glands

what are the three pairs of major salivary glands

• parotid

• submandibular

• sublingual

the three sets of the major salivary glands produce __% of the saliva volume

90%

what are the three pairs of major salivary glands

• parotid

• submandibular

• sublingual

the three sets of the major salivary glands produce __% of the saliva volume

90%

saliva is a complex fluid with multiple functions, like: (5)

• wetting

• lubricating

• digestive

• mineralization

• protective

which major salivary gland is most active during stimulation

parotid

which major salivary gland is most active during non-stimulated times

submandibular

do the parotid glands produce mostly serous or mucous secretions

serous

the parotid gland only produces __% of daily saliva volume

20%

which major salivary gland will include SIgA in their salivary secretions

parotid

do the submandibular glands primarily produce serous or mucous secretions

more serous than mucous

the submandibular glands produce __% of daily saliva volume

65% → MOST

do the sublingual glands primarily produce serous or mucous secretions

mix of mucous and serous saliva

the sublingual glands produce __% of daily saliva volume

5%

when looking histologically at a cross section of a salivary gland, there will be…

numerous lobules within each of the lobes

what is surrounding the lobes of a salivary gland

a capsule made up of connective tissue that is rich in collagen

what separates the lobes within a salivary gland

connective tissue septa (is continuous w the capsule)

what runs within the connective tissue septa

blood vessels, nerves, and excretory ducts

salivary glands are composed of a capsule surrounding a branched duct system ending in…

• acini

• compound acinar gland

• or tubules

______ (serous/mucous) acinus and ________ (serous/mucous) tubules will drain into the ____________ (striated/intercalated) ducts, and this will then drain into the __________ (striated/intercalated) duct

serous acinus and mucous tubules will drain into the intercalated ducts, and this will then drain into the striated duct

what are serous demilune

are artifacts created from incorrect preparation of the slide → ARE FAKE

how do serous cells present histologically

• stain darker than mucous cells

• pyramidal in shape

• broad based attached to basal lamina

• narrow apical end towards lumen

• polarized cell

• protein secreting cells

• round nuclei

what do serous cells secrete

a watery fluid w proteins and an alpha-amylase

what is the funx of alpha-amylase

will digest dietary starch into maltose

how do mucous cells present histologically

• are much lighter (compared to serous cells)

• pyramidal in shape

• have a flattened nuclei

• polarized cell

what do mucous cell secrete

a very mucus-rich secretion → mucin that is stored in large, light-colored vesicles

what does it mean to be a polarized cells

nuclei at one end (basal end) and secretory at the other end

are myoepithelial cells present in serous or mucous cells

serous cells ONLY

where specifically are myoepithelial cells

• present between serous cells and their basal lamina in the serous acini as branched basket cells

• along intercalated ducts

explain the origin of myoepithelial cells

are around the intercalated ducts resemble smooth muscle cells → are ectodermal in origin

what composes the duct system

• intercalated ducts

• striated ducts

intercalated ducts and striated ducts are the ___________________ ducts

intralobular ducts

what does intralobular duct mean

a duct located within a lobule of the salivary gland

characteristics of intercalated ducts

• lining of cuboidal epithelial cells

• act as stem cells for both secretory end piece cells and for the ductal cells

characteristics of striated ducts

• connect to several intercalated ducts

• are striated caused by infoldings of the basal plasma membrane for ion transport

in what duct is where the saliva composition changes

striated

excretory ducts are…

• interlobular

• have their own stem cells

are intercalated duct cells polar or nonpolar

nonpolar

intercalated duct cells are ___________ (small/big) in diameter and drain individual __________ units

small in diameter; secretory units

intercalated duct cells are responsible for the synthesis and secretion of…

lysozyme and lactoferrin

funx of lysozyme

normal protective type of enzyme

funx of lactoferrin

will slow bacteria growth: act as chelating agent, will bind to nutrient molecules on surface of oral cavity and make them unavailable to bacteria

what is the source of salivary gland stem cells

intercalated duct cells

?

intercalated duct cells

where are striated duct cells mainly found

in parotid and submandibular glands

are striated duct cells polar or nonpolar

polar

striated duct cells are have a striated appearance in basal plasma membrane w many…

mitochondria

striated duct cells predominate role

in assembly and transcytosis of SIgA

?

striated duct cells

characteristics of excretory ducts (4)

• are passive conducting tubes

• maybe pseudostratified to stratified

• contain both goblet cells and stem cells

• bilayered

?

excretory ducts

the parotid gland has the highest amount of ____ of all salivary glands

amylase

what gland is this

parotid gland

the submandibular gland is a mix of serous and mucous cells, which dominates

70% of the ducts end in serous acini and and 30% mucous acini (size will make it look like 50/50)

the submandibular and sublingual gland contains branched _____________ gland composed of serous and mucous cells

tubuloacinar gland

which gland is this

submandibular gland

the sublingual salivary gland is predominantly a mucous or serous salivary gland

predominantly mucous

which gland is this

sublingual gland

which gland is this

sublingual gland

what are the three minor salivary glands

• mucous

• serous

• mixed

what are the mucous salivary glands

• palatine glands

• posterior lingual glands

what are the serous salivary glands

glands of von ebner

what are the mixed salivary glands

• anterior lingual glands

• buccal glands

• labial glands

there are __________ (#) minor salivary glands in the oral cavity

600-1,000

what and where is the new salivary gland that scientist have discovered

tubarial glands → located near the tus tubarius, superior to the eustachian tube

is the tubarial gland a minor or major salivary gland

minor, even though its size is huge

funx of the tubarial glands

assists in swallowing

is the tubarial salivary gland primarily mucous or serous

primarily mucous glands w minor serous output

the tubarial salivary gland is quite large, so what makes it a minor gland

the location in the submucosa, the diffuse nature of the glandular tissue, and the lack of a capsule

which glands are predominant in mucous secretions

minor salivary glands: 10% of salivary excretion but 70% of the mucous secretion

characteristics of minor salivary glands

• have shorter excretory ducts

• have poorly developed intercalated and striated ducts

• are NOT surrounded by a connective tissue capsule

where are glands of von ebner located

posterolingual in the tongue

where do the secretions from the glands of von ebner go

are released in areas w significant # of taste buds → near the troughs and clefts of circumvallate and foliate papillae

do the glands of von ebner secrete serous or mucous saliva

serous fluid w digestive enzymes and other proteins

funx of the secretions from the glands of von ebner

to assist in the perception of taste

glands of von ebner can be associated w what other glands

webers glands, also posterolingual in the tongue

what does webers glands secrete in comparison to glands of von ebner

• webers: mucous glands

• VE: serous

what are the 6 steps of salivary gland development

1. bud formation

2. cord growth

3. branching of cords

4. lobule formation

5. canalization of cords

6. cytodifferentiation

what is hypohidrotic ectodermal dysplasia

the abnormal development of structures including the skin, hair, nails, teeth and sweat glands; 63% have reduced salivation

what is the only other location that would support development of salivary glands from oral ectoderm

mesenchyme from urogenital ridge

does epithelium or mesenchyme dictate the morphogenic structure

mesenchyme

does epithelium or mesenchyme dictate the product that is secreted from the gland

epithelium

what are the four important signaling pathways and growth factors for salivary gland development

• ectodysplasin A (EDA)

• sonic hedgehog

• FGF→ Fgf8/Fgf10

• EGF

what is EDA

important in BUD FORMATION, branching morphogenesis, and histodifferentiation

in mice, what would happen if there was a mutation in EDA

lack minor salivary glands

what is sonic hedgehog

• epithelial cell proliferation, survival and differentiation

• important in embryonic submandibular salivary gland growth and branching morphogenesis

what would happen if there was no sonic hedgehog

fail to progress beyond “early pseudoglandular stage”

what is FGF

• stimulates secretion of collagen- cleft formation

• lobule formation

• capsule formation for major glands

• important for branching to occur → elongation

what is EGF

stimulates epithelial proliferation and differentiation

what two way can lead to hypohidrotic ectodermal dysplasia

• deficient EDA being made by mesenchymal cells

• deficient receptors being made by epithelial cells

what week of development is bud formation happening

late week 4

what is happening in bud formation

• submandibular glands

  • EDAr expressed in epithelium

  • EDA expressed by ectomesenchyme and epithelium

what week of development is cord growth happening

early week 5

what is happening in cord growth

bud growing into ECM bc of FGF from ECM

origin of parotid gland epithelial cells

ectodermal origin

origin of submandibular and sublingual gland epithelial cells

endodermal origin

what is happening during branching of cords in salivary gland development

• clefts develop in the bud forming 2/or more buds

• growth factors Shh and TGFb from mesenchyme result in clefts from changes in epithelial cell shape

why is the ECM important for cleft formation during the branching of cords stage of salivary gland development

ECM has fibronectin and collagen III (reticular fibers) → non-muscle myosin

what is happening during lobule formation of salivary gland development

• repeated branching and budding along major branches of the cord stimulated by FGF and EGF

• E-cadherin → acinar formation

why is E-cadherin important in acinar formation

will hold the structure of the clefts in place as these will eventually become serous or mucous cells

_______________ is a requirement in branching morphogenesis

fibronectin

what components are important for branching and lobule formation to occur: (5)

• collagen III→ cleft formation

• fibronectin → cleft formation

• collagen IV→ branching, acinar morphogenesis

• proteoglycans→ branching

• laminins→ basement membrane assembly