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SALIVARY GLANDSBY: SHRIKANT PATEL112CONTENTSINTRODUCTION OF GLANDSSALIVAPROPERTIESCOMPOSITIONFUNCTIONFORMATIONSECRETIONCOTROL OF SECRETIONCLASSIFICATIONDEVELOPMENT

34STRUCTURE OF TERMINAL UNITDUCTAL SYSTEMCONNECTIV TISSUEMAJOR SALIVARY GLANDMINOR SALIVARY GLANDSALIVARY AS DIAGNOSTIC TOOLCONCLUSIONREFRENCES

5GLANDSAglandis anorganin an animal's body that synthesizes a substance for release of substances such ashormones, often into the bloodstream(endocrine gland) or into cavities inside the body or its outer surface (exocrine gland).

Glands are composed of epithelial cells specialized to synthesize and secrete special products.

Glandular epithelium consist of single cells or group of cells specialized for secretion.

67EXOCRINE GLANDS: Develop as downgrowths of an epithelial membrane and secrete onto its surface through their ducts

ENDOCRINE GLANDS : Develop in a similar way but lack ducts because they lose their connection with the surface epithelium, they release their secretory products close to the external surface of thin-walled blood vessels these products enter the blood stream.

8EXOCRINE GLANDS FURTHER CLASSIFIED :1) NUMBER OF CELLS:A) UNICELLULARB) MULTICELLULAR2) BASIS OF STRUCTURE OF DUCTAL SYSTEM:A) SIMPLEB) COMPOUNDC) TUBULAR3) BASIS OF SECRETORY PORTION:A) TUBULARB) ACINARC) TUBULOACINAR4) TYPE OF SECRETION:A) SEROUSB) MUCOUSC) MIXED5) MECHANISM OF SECRETION:A) MEROCRINEB) APOCRINEC) HOLOCRINE9UNICELLULAR: single cells interspersed among other epithelial cells of different function. Simplest in structure.

MULTICELLULAR: Occurs as many adjacent secretory cells within the epithelium (surface mucous cells of stomach); or as complex glands with ducts.

SIMPLE GLAND: single unbranched duct, which may be straight or coiled. EG: SWEAT GLANDS

COMPOUND GLANDS : branched duct system leading from a number of secretory unit. EG: FOUND IN LIVER AND PANCREASE

10TUBULAR GLANDS: Secretory units are shaped like tubules.ACINAR GLANDS: Secretory units are more round like berry or grape.TUBULOALVEOLAR GLANDS: Glands contain both tubular and alveolar secretory units. EG: SUBMANDIBULAR SALIVARY GLAND

11APOCRINE SECRETION: Is the mechanism whereby both the secretory products and a portion of apical secretory cells cytoplasm are pinched off and released.Example: mammary gland. However, the idea of apocrine secretion is no longer useful, and almost all the glands once described as apocrine are now considered to be merocrinE

HOLOCRINE SECRETION the entire cell disintegrates to secrete its substances (e.g., sebaceous glands)

MEROCRINE GLANDS cells secrete their substances byexocytosis (e.g., mucous and serous glands). Also called "eccrine".

SALIVARY GLANDS:

The salivary gland are a group of the compound exocrine gland secreting saliva.

Salivary glands are either absent or very rudimentary in animals living in water 12

oral cavity fills with considerable amounts of liquid upon opening of the jaws.

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Parasitic jawless vertebrates that feed by boring into the flesh of various species of bony fishes to suck their blood.

lampreys have a sucking mouth that does not let water get into the oral cavity.

14They are compound gland as they have more than one tubule entering the main duct.

The duct is the passage that allows the saliva to flow directly in to the anatomic location where the secretion is to be used.

They have numerous ducts associated with in them hence they are called exocrine gland.

15The architectural arrangement of the salivary gland is tubuloacinar, where acini are the secretary units.

The tubuloacinar units are merocrine as they release only the secretion of the cell from the secreting unit.

Basic functional unit of a salivary gland, Irrespective of size and location is made up of epithelial secretory cells namely serous and mucous cells and central lumen.

16SALIVA

The salivary glands are the groups of the exocrine glands secreting saliva.

Saliva has one meaning clear liquid secreted into the mouth by the salivary glands and mucous glands of the mouth which moistens and form coating around the teeth and mucosa and starts digestion of starches.

DORLAND Saliva is a clear, alkaline, somewhat viscid secretion from the parotid, submandibular, sublingual & smaller mucous glands of the mouth..STEDMEN Saliva is a clear, tasteless odorless, slightly acidic, viscous fluid consisting of secretions from the parotid, submandibular & mucous glands of the oral cavity.

17Saliva Acini

Ductal System Oral cavityThe system is a bilayer

1) Internal luminal layer - Acini & Ductal epitelium

2) external reserve layer - myoepithelium & reserve cells

Saliva serves multiple and important functions.Three major gland: Parotid SubmandibularSublingual glands. 600-1,000 minor salivary glands 18 Volume : 800 to 1500 ml secreted per day. Approx 1 ml/ minute.

Contribution from each Salivary Glands 1)Parotid Glands - 25% 2)Submandibular Glands 70% 3)Sublingual 5%

Reaction : Acidic pH 6.0 to 7.0

Specific Gravity : 1.002-1.012

Tonocity : Hypotonic to Plasma

PROPERTIES OF SALIVA19COMPOSITION20

SALIVAORGANIC SUBSTANCESINORGANIC SUBSTANCEGASES21 ORGANIC:1.PROTIEN:AmylaseLysozymeGlycoprotein'sIgATraces of blood proteinsAlbumin,IgM,IgGTransferrinLipoproteins

2.NITROGENOUS CONSTITUENTS:Amino acidsUreaUric acidAmmoniaCreatinStatherin

3.GLUCOSE

4.BLOOD GROUP SUBSTANCES A, B, O.

5.VITAMINS- WATER SOLUBLE

6.LIPIDS : Cholesterol, fatty acids, tri gycerides, phospholipids.

7.Enymes :Acid phosphataseEsterase's, Lysozyme

8.Other organic compounds:CitratesNitrates

9.Anti bacterialProteins:LysozymeSialoperoxidaseLactoferrin

99% WATER1 % SOLID22INORGANIC SUBSTANCES:sodium calciumpotassiumbicarbonatebromidechloridefluoridephosphate

GASES:

OxygenCarbon dioxideNitrogen

Normally glucose is absent in the saliva but, it is found during diabetes mellitus.

23Salivary Functions

24LubricationProtect oral mucosaModulation ofOral floraRetention of dentureBuffering actionDigestion of foodMedium ofVarious enzyme25FORMATION AND SECRETIONSecretion of each Major salivary glands is Different.

Parotid Gland Watery Serous Saliva Rich in Amylase.

Submandibular Gland Mixed Saliva.

Sublingual Gland Viscous mixed saliva.26Salivary Secretion is a 2 Stage process: 1st Stage Acini and intercalated ducts.

Primary saliva isotonic fluid

It contains oraganic components and all of the water.

2nd Stage Salivary Ducts.

Primary saliva is reabsorbed and secretion of electrolytes.

Final saliva is hypotonic.27MACRO MOLECULAR COMPONENTSAbundant rough endoplasmic reticulum and golgi complex.

RER is placed basal & lateral to the cell nucleus.

Ribosomes consist of RNA & PROTEIN. Ribosomes Nucleus by way of m RNA encoded message

Protein have a NH2 terminal extension of 16 - 30 amino acids called SIGNAL SEQUENCE.

Signal sequence is attached to membrane of RER.

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29Signal are recognized by RER with the help of certain proteins & crosses the RER membrane along with the growing polypeptide chain.Single peptidase, a proteolytic enzyme removes the signal sequence and protein newly synthesised reaches the cisternal space of RER.From here by small vesicles protein is transferred to golgi complex, here they undergo modification followed by condensation & packing into secretory granules.Golgi complex is attached to RER by budding vesicles at end of RER.

30Golgi complex : cis or convex face & trans or concave face.Buddy vesicles enter through cis face fuse with the golgi saccules .Protein migrate from cis - trance face.Packed into vacuoles.Vacuoles are know as condensing vacuoles, 2) pale secretory granules 3) immature granules.

31Thetransport mechanism is not yet clear; However a number of hypotheses currently exist. VESICULAR transport mechanism was favoured but nowevidence is coming to light to support CISTERNAL MATURATION. The two proposed models may actually work in conjunction with each other, rather than being mutually exclusive. This is sometimes referred to as thecombinedmodel.

32Immature granules are connected to the smooth membrane of the trance face.Immature granule increase in size and density to become mature.These granules are stored in the cytoplasm until they receive any secretory stimulus.Granule membrane fuse with the cell membrane at the luminal surface & contents are released into the lumen by the process of EXOCYTOSIS .SYMPATHETIC NEUROTRANSMITTER NOREPINEPHRINE

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34PRIMARY SECRETION {AT ACINI LEVEL}

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SECONDARY SECRETION{AT STRIATED DUCT LEVEL}ATP36Final electrolyte compostion rate of salivary flow.

At high flow rates saliva: in Na+ and Cl- concentration K+ concentraction

At low flow rates opposite direction.

REGULATED BY :

1) AUTONOMIC NERVOUS SYSTEM2) MINERALOCORTICOIDS

Sympathetic innervations Ducts

37REGULATION OF SALIVARY SECRETIONControlled mainly by Parasympathetic nerve signals.

Superior and Inferior Salivatory Nuclei in the brain stem.

Located at the juncture of the Medulla and the pons.

Exited by the tactile stimuli from tongue and other areas of mouth.

38Nerve supply : i)Parasymapathetic for parotid

Preganglionic Fibers aries from the inferior salivatory Nucleus in upper part of medulla oblongata

Tympanic branch of the Glossopharyngeal nerveTympanic PlexusLesser Petrosal nerve End in otic ganglion

Reach Gland Passing through Auricotemporal Branch in the Mand division of trigeminal nerve.

39 Parasymapathetic Fibers to submandibular & sublingual

Arise from the Superior Salivatory Nucleus Situated in Pons

The preganglionic fibers pass through Nervous intermedius WrisbergGeniculate GanglionMotor fibers of the Facial nerveChorda tympani Branch of Facial NerveLingual branch of trigeminal nervejoin to ganglion near gland40SYMAPATHETIC FIBERS

Arise from lateral horns 1st and 2nd thoracic segments of spinal cord.

Fibers leave the cord through Anterior Nerve Roots End in Superior Cervical Ganglion of Symapathetic chain.Travel along the Surfaces of Blood Vessels Salivary Glands41Functions of Nerve Fibers :

PARASYMPATHETIC :Secrete profuse and watery saliva.Amount of Organic constituents is less.Activate the acinar cells and Dilate the Blood Vessels of Salivary Gland.

SYMPATHETIC :Stimulation causes less secretion.Thick and rich in Mucus.Activate the Acinar Cells and cause Vasoconstriction.42CLASSIFICATIONAccording to Size.

According to Branching of Ducts.

According to Damage of Secreting Cells.

According to Secretion.

43BASED ON SIZE MajorMinorParotidSubmandibularSublingual1) Lingual mucus glands.2) Lingual serous glands.3) Buccal glands.4) Labial glands.5) Palatal glands.According to Branching of DuctsSimple Non-Branching Minor Glands.

Compound Racemose Major Glands.

44According to Damage of Secreting CellsApocrine Glands.- Glandular secretion - Free end of secreting cell is cast off along with the secretory produts accumulated.

2) Holocrine Glands.- Glandular Secretion Entire Secretory cell laden along with its Secretory Products is Cast off.

3) Merocrine Glands.- Discharge only the secretory products. Leave the secretory cell intact.

45ACCORDING TO SECRETION

SEROUSSerous Cell Thin & Watery SalivaParotid gland & Lingual SerousMUCUSMucus CellsThick & Viscous Saliva.Lingual Mucus & Buccal glandsMIXEDBoth Serous & Mucus CellsSubmanidubular, Sublingual & Labial glands.46DEVELOPEMENT OF GLAND

Parotid gland first to form during 4 6 weeks

Submandibular gland 6 weeks

Sublingual gland 8 12 weeks

All salivary gland develop similarly as initial discrete thickening of the epithelium of the stomodeum.

47Although its not clear parotid gland is believed to develop from oral ectoderm where as submandibular and sublingual are believed to develop from endodermal or ectodermal germ layers.

In absence of a general endodermal marker, it is difficult to conclude either way.

However, the endoderm is clearly capable of supporting salivary gland development given that minor salivary glands developing in the tongue, including von Ebners glands.

Despite this controversy, major salivary glands are widely regarded as ectodermal organs.

48All ectodermal organs originate from two adjacent tissues of distinct embryonic origin, (1) the epithelium (2) the mesenchyme.

Development proceeds through constant, sequential and reciprocal interactions between these two tissues translated at the molecular level by signalling molecules.

ORAL EPITHELIUM is derived from the first branchial arch.

MESENCHYMAL CELLS derived from the cranial neural crest, a migratory cell population that detaches from the embryonic neural epithelium.

49The epithelial compartment give rise to the

secretory end pieces of the salivary glands.

2) extensive network of ducts leading the salivary secretions into the oral cavity.

3) myoepithelial cells.

The mesenchymal compartment will produce the capsule surrounding the gland.

5051Taking the e.g. of submandibular gland developmentIdentification of the submandibular gland in 13 mm embryo as an out growth of the floor of oral cavity at lingulogingival groove.

An epithelial thickening appears in floor of mouth at the back of the first mandibular molar, adjacent to the developing tongue.

This thickening develops at the bottom of the alveolo-lingual sulcus, a gutter-like groove that forms in the floor of the mouth as the result of the upward growth of the tongue rudiment.

This early stage is known as the PRE BUD STAGE.

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Importantly SMG dont develop where their major excretory ducts open.Later epithelial thickening invaginates in the underlying mesenchyme of the first branchial arch. Sustained epithelial proliferation in a downward direction leads to the formation of a thick solid epithelial stalk terminated by a bulge constituting the INITIAL BUD STAGE of SMG development.

mesenchymal cells condense around the SMG primordium. This well-defined mass of connective tissue represents the capsular rudiment of the gland. The initial bud,surrounded by condensed mesenchyme, will form the parenchyma of the SMG, whereas the main excretory duct of this gland is formed by closure, in a rostral direction, of the alveolo-lingual sulcus.

53Recently in the rat submandibular gland development two basement membrane components i.e. 1) laminin & 2) type IV collegen are synthesized by the cell of glandular epithelium.Basal lamina help in primary lobe branchingType IV collegen in out growth.A thick layer of extracellular matrix (ECM) separates the epithelial and mesenchymal compartments of the salivary gland primordium. This layer, called basement membrane, is secreted partly by epithelial cells, partly by surrounding mesenchymal cells and amongst other functions primarily serves to anchor the epithelium to the underlying connective tissue. ECM is not only found in the basement membrane, but also in the interstitial matrix between cells of the connective tissue of the developing salivary gland.

54Mitosis is seen in inner cells only and rarely in outer layers.In later stage a series of morphogenetic changes, collectively referred to as branching morphogenesis, occurs in the developing salivary gland turning an initial single epithelial bud into an array of epithelial branches that will eventually differentiate into a network of ducts, each terminating in a secretory end piece.The period is called the PSEUDOGLANDULAR STAGE.

55During this phase, small invaginations or clefts form in the distal part of the initial epithelial bud, which deepen and separate the bud into usually two or three parts. This parting process establishes branch points end bud clefting is followed by outgrowth of epithelial branches (stalks) & new subsequent cleft formation in newly formed distal bud.Eventually this leads to the formation of an increasingly forger and complex tree.This parting process establishes branch points end bud clefting is followed by outgrowth of epithelial branches (stalks) & new subsequent cleft formation in newly formed distal bud.Eventually this leads to the formation of an increasingly forger and complex tree.

56Mesenchymal cells become looser, separated by extracellular matrix.Members of fibroblast growth factor protein family and their receptor along with transforming growth factor B, play a major role.Development of lumen within the branched epithelium occurs first in the distal end of the main cords, than in the proximal , finally in the central portion.Lumina is formed within the duct before they develop within the terminal buds.lumen formation may involve apoptosis of centrally located cells in the cell cords.With the formation of lumina in the terminal bulbs, further clefting occurs in the surrounding cells.

57 Terminal bulb is divided into a number of subunits called terminal tubules.The epithelium in terminal tubules consists of two layers of cells.The cells of inner layer eventually differentiate into the secretory cells of mature gland, mucous or serous, depending on the specific gland.cells of outer layer form the contractile myoepithelial cells that are present around the secretory end pieces and intercalate ducts.As epithelial components increases in size and number, the associated mesenchyme ( connective tissue ) is diminished.Thicker partitions of the connective tissuedivide the gland into lobes and lobules.

STRUCTURE OF TERMINAL SECRETORY UNITS The acini made up of epithelial secretory cells, namely serous and mucous cell n myoepithelial cells.

The cells rest on basement membrane.They are arranged in single layer.

The intercellular spaces of the apical end of the cells are separated from the lumen by the junctional complexes .

The junctional complexes hold the cells together in an acinus and regulate the permeability.

The myoepithelial cells are located on the surface of the acini.

Central lumen have star shaped morphology.The lumen via fine series of the tubes which get together to form ductal system.

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59Cells in Terminal secretory end piece: 1) Serous cells

2) Mucous cells

3) Myoepithelial cells.

60 Pyramidal in shape with broad baseand narrow apex

Spherical nucleus

Deep eosinophillic secretory granules are present.

The basal cytoplasm contain numerous cistrenae of endoplasmic reticulum. Golgi apparatus located apical or lateral to the nucleus.61

SEROUS CELLS

62 In electron microscope the immature granules appear paler in density as compared to electron dense granules.

Large number in resting call than stimulated cell

In stimulated cell they are depleted into the lumen through exocytosis.

Granules discharge through break in plasmalemma.

More microvilli in luminal plasmalemma

63MUCOUS CELLMUCOUS CELLS

The mucous secretion differ from that of the serous in two different ways: Little or no enzymatic activity Lubrication and protection of the oral tissue.

In electron microscope the granules appear swollen, their membrane are disrupted, and fused with one another.

Small granules form at the trans face of the golgi apparatus increase in size & join the rest of the granules in the apical cytoplasm.

Secretion of the mucous droplets occurs by EXOCYTOSIS.

When a single droplet is discharged its limiting membrane appear separating the droplet from lumen.

Separating membrane may then fragment, being lost with discharge of mucous or the droplet may be discharge with the membrane .

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MYOEPITHELIAL CELLS:

Conctractile cells found in relation to terminal Secretory end pieces and intercalated ducts.

Occupy space between the basal lamina and duct cells. Similar to smooth muscle cell but derived from epithelium.

STELLATE SHAPE numerous branching processes extended from the cell body to surround and embrace the end piece.

The process are filled with ACTIN and soluble MYOSIN.

In intercalated ducts FUSIFORM shape & elongated with few short processes.

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68 The processes in the acini lie in the gutter, hence the outline of the acini appears smooth, but in intercalated duct the processes runs longitudinally on the surface creating a bulge, hence k\a BASKET CELL

Ctyokeratin intermediate filament and contractile actin filaments.

In Intercalated ducts they have a fusiform shape with fewer processes & oriented length wise along the duct.

DUCTAL SYSTEMINTERCALATED DUCTSTRIATED DUCTTERMINAL DUCTS69

70INTERCALATED DUCT CELL

Simple cuboidal epithelium.

The Diameter SMALLER & lumen LARGER than end pieces.

Length of the duct is variable In major n minor salivary gland.

RER basal in position with apical Golgi regions.

A few small SECRETORY GRANULES in the apical cytoplasm.

7172 Few short MICROVILLI projecting into the lumen.

Adjacent cells junctional complexes & desmosomes.

Due to small size & lack of distinctive features, intercalated ducts are difficult to identify in routine histological sections.

LYSOZYME and LACTOFERRIN are secreted by this cells.

Undifferentiated cells may proliferate & undergo differentiation to replace damaged or dying cells in the end pieces and striated ducts.

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LIGHT MICROGRAPH OF BRANCHING INTERCALATED DUCT ( ARROWHEADS) JOINING SEVERAL SEROUS AND PIECES IN THE HUMAN SUBMANDIBULAR GLAND.

THE DUCT CELLS ARE LOW CUBOIDAL AND LIGHTLY STAINED WITH HEMATOXYLIN AND EOSIN74STRIATED DUCT CELL : Receive saliva from intercalated ducts. LARGEST PORTION Main ductal components located intra lobular . Tall columnar cells with centrally place nucleus & pale, acidophilic cytoplasm. Diameter is greater than secretory end pieces & lumen is larger than secretory end pieces and intercalated ducts. Basal lamina encloses the duct, and a capillary plexus is present in connective tissue.

75 Modify the primary saliva by reabsorption and secretion of electrolytes.76 Basal cell have nucleus located lower than other cells

Apical cytoplasm contains small secretory granules and electron lucent vesicles.

lysosomes and peroxisomes , and deposits of glycogen.

Prominent golgi regions - BASALLY

Adjacent cell joined by desmosomes & junctional complex but lack gap junctions.

Basal end have prominent striations due to numerous elongated mitochondria in narrow cytoplasmic partition, separated by highly infolded & inter digited basolateral cell membrane.

77 Are located in the connective tissue septa between extralobular or intralobular location.

Larger in diameter than striated ducts and have pseudostratified epithelium with columnar cells and small basal cells.

A large excretory duct is surrounded by dense connective tissue.

In smaller excretory duct the structure of the columnar cell is similar to that in striated ducts.

78TERMINAL EXCREATORY DUCT79 Tufts ( caveolated cells or brush ) cells, with long siff microvillai and apical vesicles are thought to be the receptor of some type of cell. Nerve endings are found adjacent to this cells Lymphocytes and macrophages are present. Dendritic cells or antigen presenting cells are present.

Light micrography of excretory duct of the human salivary gland

Small excretory duct in the interlobular connective tissue. The duct epithelium is pseudostratified, with tall columnar cells and few basal cells. Numerous capillaries and venules ( arrow head ) are present around the duct

A large excretory duct is surrounded by dense connective tissue . Pseudostratified epithelium contains several mucous gob let cells.80CONNECTIVE TISSUE

Surrounding capsule Demarcates the gland from adjacent structures.

Cells present are:1) Fibroblasts 5) Plasma cells2) Macrophages 6) Adipose cells3) Dendritic cells 7) Granulocytes4) Mast cells 8) Lymphocytes

Extracellular components :# Collagen# Proteoglycan# Elastic fibre# Glycoprotein

transcystosis Plama cells Immunoglobulins IgA, IgM, IgG

IgA as dimer complexed + j chain.

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82

1= retromandibular vein,2= external carotid artery,3= facial artery and vein,4= lingual artery and vein,5= external carotid artery,6= internal jugular vein,7= external jugular vein.BLOOD SUPPLYARTERY

SMALL ARTERY & ARTERIOLES

FOLLOW THE PATH OF EXCRETORY DUCTS

CAPILLARIES

AROUND THE SECRETORY END PIECES & STRIATED DUCTS

CAPILLARY PLEXUS

83 Venous returns follows the artery supply.

Arteriovenous anastomosis occurs in some gland.

As blood flow increases duing secretion , more blood is diverted through these anastomoses, resulting in increased venous and capillary pressures.

The resulting increases in fluid filtration across the capillary endothelim provides the fluid necessary to maintain secretion.

84MAJOR SALIVARY GLANDPAROTID GLANDSUBMANDIBULAR GLANDSUBLINGUAL GLAND85PAROTID GLAND

PAROTID GLAND

Para = around ; otic = ear

Parotid region Contains

Largest Serous Salivary Gland

Queen of the Face the facial nerve.

weighs about 20 to 30 gm.

86Situated below the External Acoustic meatus.

Between the Ramus of the Mandible & SternoCleidomastoid.

Anteriorly the Gland overlaps the Masseter muscle.

POSITION87SURFACE MARKINGS

Marked by joining Four Points

a) At the upper border of the head of the mandible.

b) Just above the centre of the masseter muscle.

c) Postero-inferior to the angle of the mandible

d) Upper part of the anterior border of the mastoid process.

88 Three sided Pyramid.

Apex of pyramid directed Downwards.

Four Surfaces :a) Superiorb) Superficialc) Antero-mediald) Postero-medial

Separeted by 3 borders: i) Anterior ii)Posterior iii) Medial

EXTERNAL FEATURES 8989 A)Superior Surface:

Forms the upper end of the gland.Small and concave.Related to : i) cartilaginous part of the external acoustic meatus.ii) Post surface of TMJ.iii) Superficial temporal vessels.iv) Auriculotemporal nerve.

9091 b) ANTEROMEDIAL SURFACE:

Related to :1) The Masseter2) Lateral surface of the TMJ3) Post border of ramus of mandible4) Medial Pterygoid5)Emerging Branches of the Facial Nerve

921)The mastoid process, with the sternocleidomastoid & the post bellly of the digastric.

2)Styloid Process with strutures attached to it.

3)External carotid artery enters the gland

4)Internal carotid artery lie deep to Styloid process.

c)POSTERO MEDIAL SURFACE:93

94LYMPHATIC DRAINAGE:

Lymphatic drainage is unique in the Parotid with Paraparotid and Intraparotid nodes.

The Paraparotid nodes are more numerous and drain the temporal region, scalp, and auricle.

The Intraparotid nodes drain the posterior nasopharynx, soft palate, and ear.

The Parotid lymphatics drain into the superficial and deep cervical lymph nodes.

95 PAROTID DUCT

JANURARY 10 1638On this date, the Danish geologist and anatomistNicolaus Steno(also known as Niels Steensen, or Stensen) was born.

During medical studies in Amsterdam, Steno discovered Stensens duct, which provides saliva from the parotid gland to the mouth.

96PATH OF PAROTID DUCT

97HISTOLOGYSecretory end pieces are all serous.Pyramidically spherical shaped acinar cells.Spherical & basally situated nucleus.Basal cytoplasam stains with basophilic dyes & granules by acidophilic dyes.Fat cells spaces often seen.Intercalated duct are long and numerous & lined by cuboidal epithelium and have lumina larger than of acini.Nuclei of myoepithelial cell may be present at basal surface of cells.Striated ducts are numerous and appears acidophilic, round, or elongate d tubules.

98Duct consists of simple columnar epithelium, with round, centrally placed nuclei.Faint striation representing the infolded basal cell membrane and mitochondria, may be visible below the nucleus.

Nuclei of myoepithelial cell may be present at basal surface of cells.

Striated ducts are numerous and appears acidophilic, round, or elongate d tubules.99

100

Situated in the Ant Part of the Digastric Triangle.Size of walnut Roughly J- SHAPED. Indented by the Post border of Mylohyoid which divide into Larger Part Superficial to muscle & small Part lying deep to Muscle. Weighs abt 8-10 gm WHARTONS DUCT 40 mm SUBMANDIBULAR SALIVARY GLAND

101Marked by an oval area Over the posterior half of the Base of the Mandible including posterior Border of the ramus.Submandibular region extends 1.5 cm above the baseBelow the Greater Cornu of the Hyoid Bone

SURFACE MARKING102Superficial Part :- Part fills the Digastric triangle.Extends upwards deep to the mandible up to the Mylohyoid line.3 surfaces --- Inferior ,Lateral, Medial

Enclosed between 2 layers of deep cervical fascia.SUPERFICIAL LAYER OF FASCIA covers inferior surface of the gland attached to base of mandibleDeep Layer Covers medial surface of the gland attached to mylohyoid lines of the mandible.

103Relations :

A)Inferior Surface is covered by Skin PlatysmaCervical Branch of Facial NerveDeep FasciaFacial VeinSubmandibular Lymph Nodes .

104B) Lateral SurfaceRelated to :Submandibular fossa on the mandible.Insertion of medial Pterygoid.Facial Artery

105C) Medial Surface

Anterior Part Related to mylohyoid muscles, nerves and vessels.ii) Middle part Hyoglossus Styloglossus Lingual nerve Submandibular ganglion Hypoglossal nerveiii) Posterior part Styloglossus Stylohyoid ligament Wall of pharynx.

106Deep Part : - Small in sizeLies deep to MylohyoidSuperficial to the Hyoglossus and Styloglossus. Posteriorly Continues with Superficial Part round the Post Border of Mylohyoid.Anteriorly Extends upto the posterior end of the Sublingual Gland.

107 Known as Whartons Duct Thin walled. Emerges at the ant end of the Deep part

Opening into the mouth at side of the frenum linguae. It had been previously described by Alessandro Achillini (1463- 1512) in 1500, but was rediscovered by Wharton in 1656. The duct is about 5 cm

SUBMANDIBULAR DUCT THOMAS WHARTON1614 - 1673108PATH OF DUCT

Open on the Floor of the mouth Sides of the Frenulum of the tongueEmerges at the ant end of the Deep partRuns forward on the HyoglossusB/w the lingual and the Hypoglossal nerve109ARTERIAL SUPPLY: The facial artery. Submental artery. Partly by the lingual artery and External jugular artery.

VENOUS DRAINAGE The venous drainage : - Anterior facial vein, -The venae comitantes of facial artery -The vein close to the Whartons duct (the hilum vein) -Seldom drained to external jugular vein and other veins

110HISTOLOGYContains serous end pieces and mucous tubules capped with seous demilunes: hence mixed glandSerous to mucous secretory end pieces vary in ratio but serous cells significantly outnumber the mucous cells.Serous end pieces are similar to that found in the parotid gland.Mucous secretory cells are filled with pale staining secretory material and little cytoplasm is avaliable.111Nucleus is compressed against the basal cell membrane and contain densely stained chromatin.Lummina of mucous tubules are larger than serous end pieces.Serous demilune cells are similar in structure to the serous end pieces and discharge their secretion into intercellular canaliculli.Intercalated and striated ducts are less numerous than in parotid but structurally similar.

112113 Smallest of the Three GlandsAlmond shaped weighs abt 3 to 4 gms15 ducts emerge from the glandsMost open Directly in the mouthFew join Submandibular Duct

SUBLINGUAL SALIVARY GLANDS

114Caspar Bartholin the Younger (secundus)Born1655Died1738

115HISTOLOGYIt is mixed gland but mucous secretory cells predominate.Mucous secretory and serous demilunes resemble those of mandibular gland.Serous end pieces are rare and appear as demilunes.Intercalated ducts are short and difficult to recognize.Intralobular ducts are fewer in numbeer than in parotid or submandibular glands.Some ducts lack the characteristic feature of infolded basolateral membranes.

116117 MINOR SALIVARY GLANDS In addition to the three pair of large salivary glands several smaller gland are located throughout the oral cavity. They are found throughout the oral cavity, except in the anterior part of the hard palate and gingiva and anterior two third of the dorsum of the tongue. There are 600 1000 minor salivary glands lying in oral cavity and oropharynx. They are predominantly mucous gland except for the lingual serous gland ( VON EBNERS GLAND )

118

Located in submucosa below the epithelium of the oral cavity , the saliva secreted reaches the oral cavity through short ducts that connect the gland to the surface epithelium1191201.Lingual glands:Can be divided into several groups:Anterior lingual gland ( gland of Blandin & Nuhn)Posterior lingual mucous glandPosterior lingual serous gland ( VON EBNERS GLAND )ANTERIOR region MUCOUS in characterPOSTERIOR region MIXED in character

1211) ANTERIOR LINGUAL GLAND:Duct open on the ventral surface of tongue near the lingual frenum.2) POSTERIOR MUCOUS GLAND:Located lateral and posterior to the vallate papillae and in association with lingual tonsils.Purely mucous in character and their duct open on the dorsal surface of tongue.1223) POSTERIOR SEROUS GLAND: Group of serous gland located between the muscle fibres of the tongue below the vallate papilla. Their ducts open into the trough of the vallate papillae and at the rudimentory foliate papillae on the side of the tongue.

1232. Labial and buccal gland :Gland of lip and cheek have been describe as mixed, consisting of the mucous tubules with serous demilunes.Ultrastrcture studies have revealed the presence of mucous cells.1243. Glossopalatine glands:Pure mucous glandPrincipally localized to the region of the isthmus in the glossopalatine fold but may extend from the posterior extension of the sublingual gland to the gland of soft palate.

4. Palatine gland:Pure mucous varietyConsists of several hundred glandular aggregates in the lamina propria of the posterolateral region of the hard palate & in the submucosa of the soft palate and uvula.125HISTOLOGY OF MINOR SALIVARY GLAND Consists of aggregates of secretory end pieces and ducts, locates in submucosa or between muscle fibre of tongue. Duct usually open on the mucosal surface. Intercalated duct are poorly developed , and larger duct may lack infolded basolateral membreane Von ebners gland are serous in character . Their secretion are released in region with significant numbers of taste buds, specifically , the trough surrounding the vallate papillae and the cleft between the vallate papillae.126 Secrete digestive enzymes and protein. Play role in taste process. Fluid secretion is thought to cleanse the tough and prepare the taste receptor for a new stimulus. Minor salivary gland are rich in mucin, antibacteriol protein, and secretory immunoglobulins. They have continous slow secretory activity and thus have important role in protecting and moistening the oral mucosa, especially at night when major salivary gland are mostly inactive.127

HISTOLOGY OF MINOR SALIVARY GLAND

128Clinical aspectsAGE:With age generalized loss of parenchymal tissue occurs.Lost cells are often replace by adipose tissue.Decrease production of salivaSome studies suggested that unstimuated salivary secretion is in normal range but decrease in volume of saliva in stimulated stage.

DISEASES:

1.DEVELOPMENTAL DISORDERS a)Abberant salivary gland b)Aplasia & hypoplasia c)Accessory salivary duct d)Xerostomia 2.OBSTRUCTIVE DISORDERS a)mucus extravasation phenomenon b)mucus retention cyst b)sialolithiasis

1293.INFECTIOUS DISEASESBACTERIAL a)Acute bacterial parotitis b)Chronic bacterial parotitis c)Acute bacterial submandibular sialadenitis d)Chronic bacterial submandibular sialadenitis e)Cat-scratch diseasesVIRAL a)Mumps b)HIV

4.IDIOPATHIC DISEASES a)Necrotizing sialometaplasia b)Cheilitis glandularis

5.AUTOIMMUNE DISEASES a)Beningn lymphoepithelial lesion b)Sjogrens sydrome c)Sarcoidosis

130XEROSTOMIA: Also known as dry mouth is the often clinincal often.Loss of salivary function or reduction in volume of saliva lead to feeling of dryness in mouth .Side effect of medication taken for other problems.Destruction of the salivary gland tissue is another common cause.After radiation therapyChemotherapy.Sjogrens syndrome: by invasion of lymphocytes into the gland and destruction of epithelial cells.131It leads to dryness of oral tissue and loss of protective effect of saliva buffers, proteins, and mucins.Oral tissue are more susceptible to caries, especially near the gingival margin.Speech, eating, and swallowing mbecomes difficult and painful.Temporary relief is achieved by sipping of water and artificial saliva.Drugs like pilocarpine can be used.132 DIAGNOSTIC APPLICATIONS OF SALIVA FOR SYSTEMIC DISEASES

Collection of saliva Whole saliva can be collected non-invasively. No special equipment is needed

Saliva can be collected with or without stimulation.

Stimulated saliva is collected by masticatory action (i.e., from a subject chewing on paraffin) or by gustatory stimulation (i.e., application of citric acid on the subject's tongue; Mandel, 1993).

133Unstimulated saliva is collected without exogenous gustatory, masticatory, or mechanical stimulation. The best two ways{draining method the spitting tube method (Navazesh, 1993).

Unstimulated saliva is not possible ,normal human salivary gland dosent secrete saliva without stimulation -saliva as an analytical tool in toxicology-KARIN M. HOLD et all

134HEREDITARY DISEASES

1) CYSTIC FIBROSIS (CF) which is considered a generalized exocrinopathy.

Saliva of patients contains increased calcium levels (Mandel et al., 1967; Blomfield et al., 1976; Mangos and Donnelly, 1981}

Elevated levels of sodium and a decrease in flow rate were reported for glands in patients with cystic fibrosis. (Wiesman et al., 1972}.

1352)21-HYDROXYLASE DEFICIENCY it is an inherited disorder which leads to congenital adrenal hyperplasia

Early morning salivary levels of 17-hydroxyprogesterone (17-OHP) were reported to be an excellent screening test for the diagnosis of non-classic 21-hydroxylase deficiency, since the salivary levels accurately reflected serum levels of 17-OHP.

136AUTOIMMUNE DISEASESSJGREN'S SYNDROME is an autoimmune exocrinopathy

Predominantly CD4+ T-cells in the salivary gland parenchyma (Daniels, 1984; Daniels and Fox, 1992)

A low resting flow rate and abnormally low stimulated flow rate of whole saliva are also indicators of Sjogrens syndrome. (Sreebny and Zhu,1996)

137 VIRAL DISEASES

Acute hepatitis A (HAV) and hepatitis B (HBV) were diagnosed based on the presence of IgM antibodies in saliva.

used for determining immunization and detecting infection with measles, mumps, and rubella (Friedman, 1982; Perry et al., 1993; Brown et al., 1994)

PCR-based identification of virus in saliva is a useful method for the early detection of HSV-1 reactivation in patients with Bell's palsy. (Furuta et al., 1998).

It was suggested that detection of IgA antibody to HIV in saliva may, therefore, be a prognostic indicator for the progression of HIV infection (Matsuda et al., 1993).

138SALIVA AS DIAGNOSTIC TOOL IN ORAL CANCER:139The most definitive procedure for oral cancer diagnosis is a scalpel biopsy, followed by the careful histopathological evaluation by a qualified pathologist. For this to be an effective procedure, it requires three consecutive events: a visit to the dentist/physicians office, the biopsy by the licensed health care provider, and a pathologists evaluation. Microscopic investigation results often are confimed too late for the cancer to treat in early stage.Despite the advance treatment and diagnostic tool invention the death rate of oral squamous cell car inoma remains the same ar before and is consider as worst among all cancer.

140The use of saliva in oral cancer is still in its infancy. Its use begun with thew report bl lio et. Al. in 2000 that exon 4 of codon 63 is mutated in salivary DNA of oral cancer patients.Five of 27 control subjects (18.5 percent) had similar mutations in their p53 gene. El-Naggar et al. in 2001 demonstrated genetic heterogeneity in saliva from patients with oral squamous carcinomas and suggested the use of epithelial cells in saliva from patients with head and neck squamous tumorigenesis for genetic analysis. 141More recently Jiang et al. reported the increase of mitochondrial DNA content in the saliva of head and neck cancer patients.319 distict protein in human whole saliva was identified using shot gun proteomics.IL-8 and thioredoxin which can discriminate slaiva of oral cancer from contrrol group have been discovered.IL-8 is significantly increasing in saliva of oral cancer patient.

142CONCLUSIONSCIENCE AND THE FUTUREThe functional value of saliva has long been thought to outweigh its diagnostic possibilities.

Recent evidence regarding saliva as a diagnostic tool for diseases such as HIV, various forms of cancer, diabetes, arthritis and heart disease has shown that much more information is contained in saliva than was previously thought

With the abundance of information that may be contained within, saliva might play an even greater role in peoples daily lives than it does today.

Scientists are transitioning from viewing saliva as a diagnostic outcast in comparison with blood or urine to viewing it as a valuable biofluid.

143The advantages of using salivary testing for diagnostic purposes are - its containment of highly diagnostic disease biomarkers. -its non invasivenature . -ability to obtain quick and reliable results.

The NIDCR initiatives and current research efforts are closing the gap rapidly between the use of saliva and other bio fluids (blood, urine, cerebrospinal fluid) for disease diagnostics.

It may well turn out that, similar to the finding that saliva is more accurate than blood in detecting oral cancer , saliva will outperform other biomedia in the diagnosis of other diseases as well

144Refrences :

Textbook of histology-WHEATERSHuman Anatomy -Vol 3 ; - B D CHAURASIAOral Histology 6th Ed.- A.R TEN CATE Text Book of Oral Pathology 5th Edition SHAFERTextbook of histology-WHEATERS ANATOMY AND PHYSIOLOGY OF THE SALIVARY GLANDS SOURCE: UTMB, Dept. of Otolaryngology DATE: January 24, 2001 Resident Physician: Frederick S. Rosen, MD Salivary diagnostics powered by nanotechnologies, proteomics and genomics David T. Wong, DMD, DMSc.

145ALWAYS THANKS TO GOD, FOR WHAT ALL WE HAVE

Serous cells are specialised for the synthesis, storage and secretion of proteins. The most prominent feature of the serous cell is the accumulation of secretory granules in the apical cytoplasm.