digestive system phki [compatibility mode]

8/8/2019 Digestive System Phki [Compatibility Mode]

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FUNCTIONFUNCTION Ingestion: oral cavityIngestion: oral cavity

Fragmentation: oral cavity, stomachFragmentation: oral cavity, stomach

Digestion: oral cavity, stomach, smallDigestion: oral cavity, stomach, small

n es nen es ne Absorption: small intestineAbsorption: small intestine

Elimination:Elimination: anal canalanal canal


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COMPONENT:COMPONENT:COMPONENT:COMPONENT:COMPONENT:COMPONENT:COMPONENT:COMPONENT:

Oral cavity

Digestive (alimentary) canal: pharynx esophagus

small intestine: duodenum, jejunum, ileum

large intestine: caecum, appendix, colon,rectum, anal canal

Glands: pancreas

liver


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ORAL CAVITYORAL CAVITYORAL CAVITYORAL CAVITY

Devided into two smaller cavity:

- Vestibule: the space between lips, cheeks andteeth

- Oral cavity proper: is bounded by the teethexternally, the floor of mouth inferiorly, and thehard and soft palates superiorly

Oral cavity is lined with stratified nonkeratinizedsquamous epithelium

Accessories organs: teeth, tongue, salivary gland


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TEETHTEETHTEETHTEETHTEETHTEETHTEETHTEETH

The anatomical features of a tooth include:

- the free enamel crown- the cervix (neck)

- the root

-

- the pulp cavity

- the apical forament

Teeth are composed of three calcified tissues thatis enamelenamelenamelenamel, dentin,dentin,dentin,dentin, and cementum,cementum,cementum,cementum, and a looseconnective tissue, the pulp.pulp.pulp.pulp.


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HUMAN TOOTHHUMAN TOOTHHUMAN TOOTHHUMAN TOOTHHUMAN TOOTHHUMAN TOOTHHUMAN TOOTHHUMAN TOOTH


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Stratified squamous epithelium

lamina propria


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groove

taste buds

lamina propria

glands of

taste buds

Stratified squamous

epithelium

Von Ebner

Circumvallate papilla Folliate papilla


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SALIVARY GLANDSALIVARY GLANDSALIVARY GLANDSALIVARY GLANDSALIVARY GLANDSALIVARY GLANDSALIVARY GLANDSALIVARY GLAND

Salivary glands secrete salivasalivasalivasaliva. Saliva aids digestionby: (1) moistening food for enzyme action and taste;

(2) lubricating the bolus for swallowing; and (3)

initiating starch conversion into simple sugar by itsprincipal enzyme, amylaseamylaseamylaseamylase.

,

located below the external ears

Submandibular glandsSubmandibular glandsSubmandibular glandsSubmandibular glands: are located under shelter

of each side of mandible in the floor of the mouth

Sublingual glandsSublingual glandsSublingual glandsSublingual glands: is located under the mucousmembrane of the tongue, near the midline of the

floor of the mouth.


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PAROTID GLAND

serous acini

salivary duct


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SUBMANDIBULAR GLAND

Connective tissue septa

lobuli

acini

Intralobular ducts


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SUBLINGUAL GLANDSUBLINGUAL GLANDSUBLINGUAL GLANDSUBLINGUAL GLAND

interlobular duct

connective tissue septa

lobuli

Intralobular ducts


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ALIMENTARY CANALALIMENTARY CANALALIMENTARY CANALALIMENTARY CANAL


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GENERAL HISTOLOGICAL STRUCTUREGENERAL HISTOLOGICAL STRUCTUREGENERAL HISTOLOGICAL STRUCTUREGENERAL HISTOLOGICAL STRUCTURE

The wall of alimentary canal consist of

four layers (tunics), from withinoutwards they are:

,

sub mucosa,

muscularis external, and

serosa or adventitia.


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MucosaMucosaMucosaMucosa, consist of:

- epithelium- lamina propria: an area of loose connective tissue

containing glands and components of circulatorysystem

- muscularis mucosa: a thin longitudinal or circularsmooth muscle

Sub mucosaSub mucosaSub mucosaSub mucosa: connective tissue zone containing

glands, blood vessels, lymphatics, and nervesMuscularis externaMuscularis externaMuscularis externaMuscularis externa: consist of two prominent layers of

smooth muscle, the inner layer is circular, the outeris longitudinal

Serosa or adventitiaSerosa or adventitiaSerosa or adventitiaSerosa or adventitia: consist of loose connectivetissue, largely of collagenous and elastic fiber; fatcells, vessels, and nerves.


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PharynxPharynxPharynxPharynxPharynxPharynxPharynxPharynx

The pharynx is fibromuscular tube extending fromthe base of the skull to the lower level of the larynx,as intersection of the respiratory and digestivesystem

The pharynx has three region:- the upper part is nasopharynxnasopharynxnasopharynxnasopharynx,

- the middle part it oropharynxoropharynxoropharynxoropharynx, and

- the lower part is laryngopharynxlaryngopharynxlaryngopharynxlaryngopharynx.


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EsophagusEsophagusEsophagusEsophagusEsophagusEsophagusEsophagusEsophagus

MucosaMucosaMucosaMucosa- epithelium a stratified squamous nonkeratinstratified squamous nonkeratinstratified squamous nonkeratinstratified squamous nonkeratin----

inizedinizedinizedinized epithelium

- lamina propria contain esophageal cardiac

glands producing mucus- muscularis mucosa is composed mostly of

longitudinal smooth muscle fibers

proper producing mucus to facilitate the movement offood down the esophagus

Muscularis externaMuscularis externaMuscularis externaMuscularis externa inner: circular; outer: longitudinal

- the upper third: skeletal muscle fibers

- the middle third: skeletal and smooth muscle

fibers

- the lower third: smooth muscle fibers

AdventitiaAdventitiaAdventitiaAdventitia:

attaches the esophagus to the trachea


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EsophagusEsophagusEsophagusEsophagusEsophagusEsophagusEsophagusEsophagus

Lumen

Stratified squamous epithelium

Lamina propria

Muscularis mucosa

Sub mucosa

Circular layer of muscularis

Longitudinal layer of muscularis

Adventitia


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StomachStomachStomachStomachStomachStomachStomachStomach

Devide into four region; (1) cardia, (2) fundus, (3)body or corpus, and (4) pyloris

MucosaMucosaMucosaMucosa of the empty stomach is thrown into the deep,make irregular longitudinal folds called rugae.rugae.rugae.rugae. The

,

invaginates into the lamina propria to form gastricgastricgastricgastricpitspitspitspits (foveolaefoveolaefoveolaefoveolae)


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The cell lining the gastric glands of mucosa are:

- surface epithelium (simple columnar) secrete

mucus

- chief (zymogenic) cells produce the digestive

enzymes pepsin, rennin and lipase- parietal (oxyntic) cells produce hydrocloric acid

- mucous neck cells along with the surface epithelium

presumably protect the stomach lining fromautodisgestion by HCl

- enteroendocrine cells secrete gastrointestinalhormones (secretin, gastrin, cholecystokininsecretin, gastrin, cholecystokininsecretin, gastrin, cholecystokininsecretin, gastrin, cholecystokinin)


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Sub mucosaSub mucosaSub mucosaSub mucosa contains Meissners nerve plexus

Muscularis mucosaMuscularis mucosaMuscularis mucosaMuscularis mucosa has three layers of smoothmuscle:

- inner: oblique layer

- middle: circular layer

- outer: lon itudinal la er

Between circular and longitudinal layer liesAuerbachs myenteric nerve plexus


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Stomach with gastric pits


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SMALL INTESTINESMALL INTESTINESMALL INTESTINESMALL INTESTINESMALL INTESTINESMALL INTESTINESMALL INTESTINESMALL INTESTINE

The small intestine of human being is composed ofthree regions:

- duodenum, 25-30 cm long- jejunum, 2,5-3 m long

- ileum, 4-4,5 m long

Function:

- to complete the digestion of food by appropriate

enzymes

- to selectively absorb the finished product ofdigestion into the blood and lymph vessels


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GENERAL HISTOLOGICAL STRUCTURE OFGENERAL HISTOLOGICAL STRUCTURE OFGENERAL HISTOLOGICAL STRUCTURE OFGENERAL HISTOLOGICAL STRUCTURE OFGENERAL HISTOLOGICAL STRUCTURE OFGENERAL HISTOLOGICAL STRUCTURE OFGENERAL HISTOLOGICAL STRUCTURE OFGENERAL HISTOLOGICAL STRUCTURE OFSMALL INTESTINESMALL INTESTINESMALL INTESTINESMALL INTESTINESMALL INTESTINESMALL INTESTINESMALL INTESTINESMALL INTESTINE

The mucosamucosamucosamucosa form villi - projections that extend into thegut lumen. The villi covered with simple columnarabsorptive epithelial cell and goblet cells interposedthem. The surface of columnar epithelial cells provided

with microvilli to increase the surface absorptive area.The lamina propria contain intestinal glands, known ascrypts of Lieberkuhn that composed by columnare ithelial cells oblet cells Paneth cells and

enteroendocrine cells. The last cells secrete intestinalhormone such as secretin and cholecystokinin.

The muscularis mucosamuscularis mucosamuscularis mucosamuscularis mucosa consist of an inner circular andan outer longitudinal layer of smooth muscle

The sub mucosasub mucosasub mucosasub mucosa contains Meissners nerve plexus The muscularis externamuscularis externamuscularis externamuscularis externa, with Auerbachs myenteric

plexus intervening.


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DuodenumDuodenumDuodenumDuodenumDuodenumDuodenumDuodenumDuodenum

Special characteristic :Special characteristic :Special characteristic :Special characteristic :

abundant leaf-shaped villi, but lowestlowestlowestlowest in height

prominent Brunners gland in the sub mucosa

an incomplete serosa replaced by an extensive

a ven a

the termination of bile and pancreatic ducts


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1. Mucosa1. Mucosa1. Mucosa1. Mucosa

2. Submucosa2. Submucosa2. Submucosa2. Submucosa

3. Muscularis mucosa3. Muscularis mucosa3. Muscularis mucosa3. Muscularis mucosa


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Intestinal villi

Simple columnar epithelium

Lamina propria

Crypt of Lieberkuhn

Muscularis mucosa

Submucosa


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Brush border

Lamina propria

Goblet cell

INTESTINAL VILUS OF DUODENUMINTESTINAL VILUS OF DUODENUMINTESTINAL VILUS OF DUODENUMINTESTINAL VILUS OF DUODENUM


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JejunumJejunumJejunumJejunumJejunumJejunumJejunumJejunum

Special characteristic:

the fingerlike villi are the tallesttallesttallesttallest in height

the lacteals are well developed for maximum fat

absorption

J jJ j


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JejunumJejunum


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Jejunum with villiMuscularis

Glands

Villi

Lumen


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IleumIleumIleumIleumIleumIleumIleumIleum

Special characteristic:

abundant lymph nodules (Peyers patchesPeyers patchesPeyers patchesPeyers patches) in lamina

propria of the mucosa.

IleumIleum


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IleumIleum


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IleumIleumIleumIleumIleumIleumIleumIleum

1. Mucosa

2. Lymph nodule

3. u mucosa

4. Muscularis externa


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LARGE INTESTINELARGE INTESTINELARGE INTESTINELARGE INTESTINELARGE INTESTINELARGE INTESTINELARGE INTESTINELARGE INTESTINE

Is composed of cecum, appendix, colon, rectum,anal canal

The large intestine possesses no villi

Contain crypts of Lieberkuhn in its lamina propria

Function:- absorbs water

- forms feces


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CecumCecumCecumCecumCecumCecumCecumCecum

That is the beginning of large intestine, a large

blind sac that extends caudad beyond the ileocecalvalve

Pro ectin from the blind end of the cecum is the

vermiform appendix, a small worm- shaped tube(about 10 cm long, 1 cm wide). It characterized by

multiple and large lymph nodules in the lamina

propria.

C lC lC lC lC lC lC lC l


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ColonColonColonColonColonColonColonColon

About 1,3 m long, consist of ascending,transverse and descending regions

The surface epithelium consist of threetypes of cells:

- sim le columnar absor tive cells

---- abundant goblet cellsgoblet cellsgoblet cellsgoblet cells- stem cells give rise to the absorptivecells

The crypts of Lieberkuhncrypts of Lieberkuhncrypts of Lieberkuhncrypts of Lieberkuhn of the laminapropria are longer than those of the smallintestine, contain numerous goblet cellsgoblet cellsgoblet cellsgoblet cells

The muscularis mucosa consist of inner circular


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The muscularis mucosa consist of inner circular

and outer longitudinal smooth muscle layers

The sub mucosa resembles that of the jejunum or

ileum

The muscularis externa is composed of inner

circular and outer longitudinal smooth muscle

layers. Auerbachs plexus occupied between the

teniae coliteniae coliteniae coliteniae coli, three flat ribbons of longitudinallysmooth muscle. These are responsible for the

formation of haustra colihaustra colihaustra colihaustra coli (sacculation)

The colon has both serosa and adventitia. Theserosa presents small, fat-filled pouches, the

appendices epiploicaeappendices epiploicaeappendices epiploicaeappendices epiploicae


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ColonColonColonColon

Simple columnar epithelium

Lieberkuhn Gland

Lamina propria

Muscularis mucosa

Submucosa

Muscularis externa


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RectumRectumRectumRectumRectumRectumRectumRectum

10-12 cm long

The teniae coli flatten out to form a uniform,

longitudinal sheet of muscle

The mucosa is thicker wih prominent submucosalveins

Crypts of Lieberkuhn are longer (0.7 mm), are linedalmost entirely by goblet cells

Lymph nodule are less abundant

Its serosa is progressively replaced by an adventitia


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Anal canalAnal canalAnal canalAnal canalAnal canalAnal canalAnal canalAnal canal

2.5-4 cm long

The mucosa, sub mucosa and a few longitudinallysmooth muscle fibers form 6-10 longitudinal folds

called anal columns of Morgagni The epithelium is stratified squamous type. At the

anal orifice, the epithelium joints the epidermis of.

enlarged apocrine-type sweat gland, the circumanal gland,,,, and sebaceous gland are present.

At the anal orifice, the circular layer of smoothmuscle thickens to form the internal anal sphincter

More distally the superficial skeletal muscle fiberare organized into the external anal sphincter.


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GLANDSGLANDSGLANDSGLANDSAssociated WithAssociated WithAssociated WithAssociated WithAssociated WithAssociated WithAssociated WithAssociated With

LIVERLIVERLIVERLIVER PANCREASPANCREASPANCREASPANCREAS


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LiverLiverLiverLiverLiverLiverLiverLiver

The liver is the largest gland of the body, 1200-1500 g

weight, surrounded by Glissons capsuleGlissons capsuleGlissons capsuleGlissons capsule, a thin

connective tissue.

Anatomical unit of liver is he atic lobule. It is

polyhedral or hexagonal, surrounded by a connectivetissue derived from Glissons capsule.

Hepatic lobule:


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Hepatic lobule:

- at the center of each lobule lies a central vein,a branch of hepatic vein

- contains sheets or plates of hepatic cells

(hepatocytes) radiate outward from the

central vein. Between the plates of hepatic cells liesblood sinusoids that partially lining by Kupffer cells,a phagocytic cell for engulf whole and fragmented

.

- area in the middle of three adjacent hepatic lobulecalled portal area or portal canal. It

contains arteriole hepatic, portal venule, nerves,lymphatics, bile ducts, and fat.


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As the exocrine gland, liver synthesize bile by its

hepatocytes storage in gallbladder lead to

duodenum for emulsify fats and increase absorption

of lipids.

As the endocrine gland, liver synthesize and

release numerous lasma rotein and com onents,

such as fibrinogen, urea, albumen, prothrombin,and lipoproteins.

LiverLiverLiverLiverLiverLiverLiverLiver


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Hepatic lobule

Portal connective tissue

(Glissons capsule)

Central vein

Portal triad

One portion of pigs liver


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Central vein of a liver lobule HepatocytesSinusoids


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Branch of the hepatic artery

Branch of the bile duct

Branch of the Portal vein

Portal triad of liver

Portal connective tissues

Hepatocytes

PPPPPPPP


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PancreasPancreasPancreasPancreasPancreasPancreasPancreasPancreas

Exocrine portion(90%)

Endocrine portion

(10%)

Exocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreas


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Exocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreasExocrine portion of pancreas

The exocrine portion is a compound acini gland,

composed of 6-8 low columnar or pyramidal

serous cells surrounding a small lumen.

Secretion: ancreatic uice contain enz mes

trypsin, amylase, maltase, and lipase

lead toduodenumfor help digestive function.

Endocrine portion of pancreasEndocrine portion of pancreasEndocrine portion of pancreasEndocrine portion of pancreasEndocrine portion of pancreasEndocrine portion of pancreasEndocrine portion of pancreasEndocrine portion of pancreas


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ndocrine portion of pancreasEndocrine portion of pancreasEndocrine portion of pancreasndocrine portion of pancreasndocrine portion of pancreasEndocrine portion of pancreasEndocrine portion of pancreasndocrine portion of pancreas

The endocrine portion is islets of Langerhans or

islets tissue, are scattered among the acini.

Islets of Langerhans consist of:

- alpha cells: are located mostly on the periphery of

islets, compose about 20% of the cells population;

secrete glucagon (glycogen glucose)

- beta cells: smallest, most numerous (70%), are

located on the central area of islets; secrete

insulin (glucose glycogen)

- delta cells: largest, few (5%); secrete somatostatin

(inhibit the release of growth hormone)


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PPPPPPPP


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PancreasPancreasPancreasPancreasPancreasPancreasPancreasPancreas

Connective tissue septa

Acini glands

Islets of Langerhans


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Centroacinar cells

Islet of Langerhans

Acini glands

Exocrine and endocrine gland of pancreas

digestive system phki [compatibility mode]

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