Salivary glands

major salivary glands (3)

-parotid

-submandibular

-sublingual

How much saliva do the major salivary glands produce

90%

Functions of saliva (5)

- wetting

- lubricating

- digestive

- mineralization

- protective

What does the parotid gland secrete?

- produces a serous (watery) secretion

what percentage of the daily saliva volume is produced from the parotid gland

20 %

What is included in the secretion from the parotid gland

-SIgA

-defense chemicals

what percentage of the daily saliva volume is produced from the submandibular glands

65 %

what does the sublingual gland predominantly produce

-mucous saliva

what percentage of the daily saliva volume is produced from the sublingual gland

5 %

What does the submandibular gland secrete

-mixed serous and mucous secretion

What is the capsule of connective tissue of the salivary gland made up of? What is it continuous with?

-collagen fibers

-continuous with the connective tissue septa

What runs within the connective tissue septa

-blood vessels

-nerves

-excretory gland

What glands are mostly being activated when we are eating

parotid gland

Salivary gland structure

-composed of lobules within lobes

if salivary glands end in compound acinar glands, what do they secret

serous

if salivary glands end in tubules what do they secrete

mucous

serous cells secretion

-produce watery secretion with proteins

-alpha amylase

What secretes alpha amylase

serous cells

function of alpha amylase

digest dietary starch into maltose

shape of serous cells

-pyramidal

serous cell nucleolus shape? Polarized or non-polarized cells?

-round

-polarized cells

compound acinar gland

made of serous-secreting cells that dump into intercalated duct

Mucous cell shape

pyramid

mucous cell nuclei shape?

polarized or non-polarized cells?

-flattened nuclei

-polarized cell (nuclei near basal end)

What do mucous cells produce and where is it stored?

-mucus-rich secretion (mucin) stored in large light-colored vesicles

where are myoepithelial cells present

- in the serous acini (between serous cells and their basal lamina) as branched “basket cells”

-also along intercalated duct (spindle shaped)

what covers the acini and intercalated ducts surface area

myoepithelial cells

origin of myoepithelial cells around the intercalated duct

ectoderm (but resemble smooth muscle)

where does the Duct system of the salivary gland empty into

-empties into intercalated duct which flows into striated duct

Function of intercalated duct

-lining of cuboidal epithelial cells

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

Both ducts (striated and intercalated) of the salivary gland are _______ ducts

intralobular

What are striated ducts connected to

-connected to several intercalated ducts

Why are striated ducts striated

-caused by infoldings of the basal plasma membrane (for ion transport)

excretory ducts are _____ and have their own stem cells

interlobular

polar or nonpolar: intercalated duct cells

nonpolar

what cell? small diameter and drain individual secretory units

intercalated duct cell

what do intercalated duct cells synthesize and secrete

-lysozyme

-lactoferrin

what is the source of salivary gland stem cells

intercalated duct cells

Where are striated duct cells mainly found

-parotid and submandibular glands

polarized or nonpolarized: striated duct cells

polarized

role of striated duct cells

-assembly and transcytosis of SIgA

What two cells do excretory ducts contain

-goblet cells

-stem cells

what type of epithelium is found in excretory ducts

-pseudostratified to stratified

What is the parotid gland composed of

100% serous acini

What gland has the highest amount of amylase

parotid gland

When is saliva secreted from the parotid gland

-during eating (stimulated saliva)

When is the saliva mainly produced from the submandibular salivary gland

-mostly resting saliva

functions of the serous cells in the submandibular salivary gland

-secrete lysozyme to kill bacteria

When is the saliva of the sublingual salivary gland mainly produced

-resting saliva

what glands are branched tubuloacinar glands

all major salivary glands

Mucous minor salivary glands (2)

-palatine glands

-posterior lingual glands

serous minor salivary gland

glands of von ebner

Mixed minor salivary glands (3)

-anterior lingual glands

-buccal glands

-labial glands

New salivary gland that was discovered in 2020

-tubarial gland (minor salivary gland- mainly mucous gland)

function of tubarial gland

assist in swallowing

Where are minor salivary glands found

-submucosa

minor salivary glands produce 70% of _______ secretion

mucous

When is saliva produced in the minor salivary gland

Important contributors to unstimulated or resting saliva

are minor salivary glands surrounded by a connective tissue capsule

no

location of glands of von ebner

posterolingual in the tongue

Where are glands of von ebner secretions released

-in areas with significant numbers of taste buds

what do Von ebner glands secrete

-serous fluid with digestive enzymes and other proteins which assist in the perception of taste

what are von ebner glands associated with

-webers glands (mucous gland)

salivary gland development (6 steps )

1. bud formation (Eda)

2. cord growth (FGF)

3. branching of cords (sonic hedgehog)

4. lobule formation (EGF/FGF)

5. canalization of cords

6. cytodifferentiation: formation of acini

Differences between facial exocrine glands and exocrine glands located elsewhere in the body

-ectomesenchyme reacts differently than mesenchyme

-less reciprocal induction signals received from ectomesenchyme

-higher degree of epithelial interactions in salivary glands

teeth and sweat glands have less reciprocal induction signals, instead they are more affected by _________

hypohidrotic ectodermal dysplasia

oral ectoderm derived organs (2)

-tooth

-salivary glands

What regulated the morphogenetic (shape) events of various ectodermal organs

mesenchyme

what determines if a gland with be mucous or serous

epithelial cells

what cell is important in bud formation during salivary gland development

ectodysplasin A (Eda)

function of sonic hedgehog

-epithelial cell proliferation, survival and differentiation

what is important in Embryonic submandibular salivary gland cord growth and branching morphogenesis

sonic Hedgehog

FGF funciton

-stimulates secretion of collagen- cleft formation

EGF function

stimulates epithelial proliferation and differentiation

what is important for branching to occur in the salivary gland development

FGF

What is defective in hypohidrotic ectodermal dysplasia

-Eda (bud formation)

-FGF (cord growth)

salivary gland development:

What simulates bud formation?

-stimulated by Eda from ECM on epithelium

salivary gland development stage: oral epithelium form a bud growing into ECM

bud formation

salivary gland development stage? bud growing into ECM because of FGF from ECM

cord growth

origin of parotid gland epithelium

ectoderm

origin of submandibular and sublingual glands epithelium

-endoderm

salivary gland development stage? clefts develop in the bud forming two or more bud

-branching of cords

What growth factors result in clefts from changes in epithelial cell shape

-Shh

-TGFb

what role does fibronectin and collagen III play in the branching of cords

-cleft formation

salivary gland development stage:

result of repeated branching and budding along major branches of the cord

What is this stimulated by?

lobule formation

-FGF, EGF

salivary gland development: lobule formation: what is important in acinar formation

E-cadherin

________ is a requirement in branching morphogenesis

fibronectin

collagen III funciton in development

cleft formation

fibronectin function in development

cleft formation

collagen IV funciton of development

-branching (acinar morphogenesis)

proteoglycans function of development

-branching

laminins function of development

Basement membrane assembly

- Lumen formation

- FGFR signaling

- Acinar formation

How can branching be inhibited

-treatment of collagenase --> no clefts form

How to block the formation of terminal end buds

-using antibodies to block collagen IV

What do all ducts form before?

the formation of

acinar cells and secretory granules.

what stem cells undergo cell proliferation? What do they differentiate into?

cells of the bulb region

-differentiate into acinar cells and ductal cells

what cells arise from the stem cells of the terminal bulbs

-myoepithelial cells

important growth factors of minor salivary glands

-Eda

-sonic hedgehog (Shh)

-FGF

mutations of minor salivary glands cause

-hypohidrotic ectodermal dysplasia

unconditional reflexes of saliva production

-gustatory stimulus (taste)

-masticatory stimulus (chewing)

-olfactory stimulus (smelling)