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The doctor started the lecture talking about how important is the previous

lecture ( oral muscosa) and said that there 's going to be 20% of the final

exams questions on that topic .And here we start the lecture entitled

Salivary glands , please read it carefully as many slides are not required .

Salivary glands :

Salivary glands are: -

_ compounds ,which means more than one tubule entering the main duct

(it's not simple that consists of one duct )

- Tubuloacinar , we have tubules and acini (singular :acinus ) ; these are

the areas where saliva is synthesized (saliva is synthesized in acinus and

secreted into ducts )

-Merocrine, because only the secretion of the cells is released (y3ne we

dont have any material from blood that comes into saliva , thats why we

call saliva as marocrine secretion )

-Exocrine , secretion into a free surface (opposite to endocrine ;secretion

into blood )

Physiology:

we will not mention it as we are going to discuss it in details in oral

physiology .

classification of salivary glands :

we classify salivary glands due to size into :Major and Minor glands .

_Major salivary glands :Parotid ,Submandibular ,Sublingual . (wealready learnt about that in anatomy )

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** just to remember quickly : the parasympathetic

activity of the parotid gland from glossopharyngeal nerve .

but the parasympathetic activity of both Submandibular and

Sublingual glands is from facial nerve through chorda

tympanie . (thats not important )

_minor salivary glands :

They are scattered throughout oral mucosa .

Labial, buccal, palatoglossal, palatal, and lingual mucosae ; all have

salivary glands ,

Its notpresent in in the gingival (important note ) , and also its not

present in the mid palatine propria ( middle area in the hard palate ) .(Important information for fifth year mshan ma erasebna sani khamse :P )

Acoording to secretion we classify glands to : mucous , serous and mixed

.

If the secretion was mucoid( ) then its mucous .

If there secretion was watery ()then its serous .

If mixed ( ) then its mixed . (serous and mucous at the same

time )

Saliva & fuction of saliva :

We will not discuss saliva as we are going to dicuss it in physio .

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Sali ary glands :

The mai ti e element in the sali ary gland : any sali ary gland has

t main elements : glandular secret ry tissue ( the gland itsel ) & the

surrounding connecti e tissue .

The glandular connecti e tissue is called parenchyma , and it s ectodermal

in origin (y3ne da2eman el gland aselha invagination mn el epithelium el

5areje )

*** Remember: All major and minor salivary glands originate from oral

mucosa ::

Invagination duct form the gland .

And also the supporting connective tissue here in this picture we see theparenchyma ( the yellow color with blue , this is the glandular part , but

the whole structure is surrounded by a connective tissue ( the supporting

connective tissue )

The supporting is called strome ,and this is mesodermalin origin (not

ectodermal ).

-From macro to microscopic level: we have:

Glands divided into a number of lobes each lobe is a

number oflobules each lobule we find a number of secretory

units called Acini (singular:acinus ) .

-The secretory units in the salivary glands :

These are A grape-li e cluster of parenchymal cells around a lumen

( ) .

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There are three types of acini : serous , mucous and mi ed (mucous

covered with serous ) .

So when we have mi ed acini , the cells that are related to lumen are :

mucous ; and from outside :serous ( we callit serous semiluned (

) .

In addition to that we have cells that are called myoepithelial cells that

are located around acini . these cells function in squeezing the contents (

here saliva is formed and it s collected in lumen so we need a big cellto

contract and squeeze saliva and getitinside ) .7these are contractile cells

with several processes ,,, also called basket cells .

The duct system :

We have : - Acinus lumen:the place where cells secrete directly and anumber of lumens empty in an Intercalated duct and a number of

intercalated ducts empty in Striated duct .

Acinus lumen Intercalated duct Striated

duct .

These are called intra-lobular (located within the lobule ) .

The collecting ducts are located between lobules that s why collecting

ducts are usually surrounded by connective tissue .

*The inter-lobular system is inert, the composition of saliva doesn't

change as soon as it arrives in the collecting duct .

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As long as saliva is in the lumen , in the intercalated duct , in the striated

duct ; the composition of saliva can change ,we can have addition or

absorbtion of electrolytes , proteins . Etc .

Strome :

Is a connective tissue that surround the salivary gland , it's mesenchymal

in origin .

From Macro-to-Microscopic levels :

Capsule inter lobar (spaces between lobes ) interlobular

(spaces between lobules ) inter acinus (between acini ) .

As any connective tissue it contains : collagen fibers , fibroblasts and fatcells .

*remember that fat cells increase with age .

For example : in foreinsic we found only salivary gland that belongs to a

dead person and we want to know his age ; we take it and examine the

amount of fat cells , if we found many fat cells then the person is old and

if we find less he is young .

Synthesis of saliva :

Synthesis of saliva is active (it needs energy ) , thats why its not a blood

ultra filtrate (saliva isn't filtrated blood , its synthesis is active process and

needs energy ) .

_serous cells , they actually secrete Watery proteinaceous fluid contains

Amylase . amylase is an important enzyme that digests starch into

dissacharide .

_mucous cells , contains Proteins linked to a greater amount ofcarbohyrates

_ Plasma cells ,secrete IgA immunoglobulin A for protection .

Secretion of saliva :

we will not be asked about it as it is oral physiology topic .

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we need to know the difference between serous cells and mucous cells

, if we see serous cell , how can we know that this is a serous or

mucous cell ?

In light microscopy : serous cells are basophilic ( they stain dark )

Mucous cells , pale (almost white ) as they contain

carbohydrates

Second , serous cells contain round prominent nucleus .

in mucous cells ,flattened .

ONLY those thing are required to distinguish between them

SLIDE 14 this picture wasnt discuused .

, dont worry about it .Myoepithelial Cells

we have to know one function of it : to squeeze the content ofJust

acinus to empty the content of acinus into intercalated and striated

ducts .

intercalated ducts :The

.Drainage from several acini.

_ Compressed between the acini : because they are thin and small .

_contain Cuboidal epithelial cells : one single layer .

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Prominent nuclei

In Parotid, they are long, narrow, and branching .

(important , at least one question ):Striated ducts

_Larger and longer than ICD ._ Simple columnar epithelium surround with one layer of cells .

_Cells have large centrally-located nuclei : nuclei located in the

middle of the cell .

Called striated because the basal surfaces of the cell have many

folding , the folding produce striations .

_ the luminal part also the cell membrane has folding and

microvilli to increase the surface area for secretion and absorption .

_cells are attached by desmosomes .

_at the level of striated ducts we have much of the change in the

composition of saliva .

Collecting ducts :

Collecting ducts are bilayered .

**** how can we distinguish between collecting ducts and striated??

e around the duct and ifif you dont see connective tissu Rule :

you only see one single layer this is striated .

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if you see more than one layer and see much connective tissue

around the duct its collecting .

its bilayered epithelium , luminar part is columnar epithelium layer

and basal part is cuboidal .

the collecting ducts approach to the surface of oralmucosa it becomes more than two layers , the bigger itis , the more connective tissue it has .

so Terminated as stratified epithelium to merge with the oralmucosa.

:Parotid gland

its the largest gland and it contains serous acini .

Parotid gland only gives watery secretion it doesnt produce mucous .

* so in the exam if there are glands , and in the glands all the acini arebasophilic (purple in colour ) know that this is a parotid gland , its

possible that it is von ebners gland .

*the white parts here are fat cells .

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Submandibular gland :

We see light cells and dark cells so its mixed , if theres more mucous its

submandibular .

Intercalated ducts are short and difficult to locate_

Striated ducts are long and obvious

Although submandibular glands are mixed there is more mucous

than serous .

Sublingual glands :

Are mixed and have more mucous than serous (most of the cells

are light in colour )

They lacks striated ducts .

Minor salivary glands :: are primarily mucous .

As you go posteriorly there is a tendancy for the glands to become

mucous ,

In the picture orange areas glands are mucous , blue area such as

:tip of the tongue , lips , cheeks are mixed glands .

We have the only serous minor salivary gland which von ebnergland which is associated with circumvallate papilla .

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FINALLY : WISH YOU ALL GOOD LUCK AND SORRY FORANY

MISTAKE!!!!,

Watch your thoughts; they become words.

Watch your words; they become actions.

Watch your actions; they become habits.

Watch your habits; they become character.

Watch your character; it becomes your destiny. ;)

Special thanks to my brother saif who helped me a lot , and thanks to my

friends too

wish you all good luck in your exams