The gastro The gastro intestinal systemintestinal system

By By

Dr. Mohammed Ahamed AbuelnorDr. Mohammed Ahamed Abuelnor

Functions of the GITFunctions of the GIT Transport and food digestionTransport and food digestion Absorption of foodAbsorption of food Secretion of hormones and enzymes of digestionSecretion of hormones and enzymes of digestion Production of mucus for lubrication of ingested foodProduction of mucus for lubrication of ingested food

The parts G.I.TThe parts G.I.T Parts of the G.I.T are :-Parts of the G.I.T are :- Elmantry canal formed of :-Elmantry canal formed of :- Oral cavityOral cavity The pharynxThe pharynx The esophagusThe esophagus The stomachThe stomach The small intestineThe small intestine The large intestine The large intestine Accessory glands : salivary glands liver Accessory glands : salivary glands liver

pancreases pancreases

The basic layers of the The basic layers of the G.I.TG.I.T

The mucosa: it is the inner layer formed The mucosa: it is the inner layer formed ofof

EpitheliumEpithelium Lamina proporiaLamina proporia Muscularis mucosaMuscularis mucosa The sub mucosaThe sub mucosa The musculosaThe musculosa The serosaThe serosa

Histology of GITHistology of GIT Schematic diagram showing different Schematic diagram showing different

layers of GITlayers of GIT1.1. MucosaMucosa

2.2. SubmucosaSubmucosa

3.3. MuscularisMuscularis

4.4. SerosaSerosa

MucosaMucosa Consists of:Consists of:Lining epithelium made of Lining epithelium made of simple columnar epitheliumsimple columnar epitheliumIt sits on a basement It sits on a basement membrane membrane Lamina propria made of loose Lamina propria made of loose connective tissue bfull of connective tissue bfull of macrophges and lymphocytesmacrophges and lymphocytesMuscularis mucosae separate Muscularis mucosae separate mucosa from submucosa mucosa from submucosa contraction of which leads to contraction of which leads to increase contact of epithelium increase contact of epithelium with foodwith food

SumucosaSumucosa Consists of a layer of Consists of a layer of

dense connective dense connective tissuetissue

Rich in blood vessels Rich in blood vessels Contains submucosal Contains submucosal

nerve plexusesnerve plexuses Some times it may Some times it may

contain mucus glandscontain mucus glands

MuscularisMuscularis Generally, it consists of Generally, it consists of

two layers of smooth two layers of smooth muscle fibersmuscle fibers

Inner circular and outer Inner circular and outer longitudinallongitudinal

Myenteric nerve Myenteric nerve plexuses are distributed plexuses are distributed between the two muscle between the two muscle layerslayers

With the submucosal With the submucosal nerve plexuses, they nerve plexuses, they help propel and mixing help propel and mixing the foodthe food

SerosaSerosa It is a layer of loose It is a layer of loose

connective tissue connective tissue covered by a layer of covered by a layer of simple squamous simple squamous epithelium called epithelium called mesotheliummesothelium

It contains the It contains the lymphatic and blood lymphatic and blood vessels of the GI tract vessels of the GI tract and fat tissueand fat tissue

Oral cavityOral cavity Is lined with stratified squamous Is lined with stratified squamous

epithelium to protect the mouth epithelium to protect the mouth from the effect of foodfrom the effect of food

Soft palate, floor of the mouth, Soft palate, floor of the mouth, lips, and cheeks are lined with lips, and cheeks are lined with non-keratinized epitheliumnon-keratinized epithelium

Lamina propria contains many Lamina propria contains many diffuse salivary glandsdiffuse salivary glands

The pharynxThe pharynx It is the part of the G.I.T which extend from the base of It is the part of the G.I.T which extend from the base of

the skull to the esophagusthe skull to the esophagus The function of the pharynx is the swalling of the food The function of the pharynx is the swalling of the food The histological structure of the pharynxThe histological structure of the pharynx The mucosa: formed of stratified squamuse non The mucosa: formed of stratified squamuse non

keratinized epitheliumkeratinized epithelium The sub mucosa: formed of loose tissue contain blood The sub mucosa: formed of loose tissue contain blood

vessels, nerve fibers and lymphatic tissuevessels, nerve fibers and lymphatic tissue The musculosa: formed of skeletal muscleThe musculosa: formed of skeletal muscle The serosa: formed of deep fascia formed of collagen The serosa: formed of deep fascia formed of collagen

fibers fibers

The esophagusThe esophagus

It is muscular tube extend from the It is muscular tube extend from the pharynx to the stomach passes through pharynx to the stomach passes through the neck, the chest, and the abdomenthe neck, the chest, and the abdomen

It is function is the swalling of the foodIt is function is the swalling of the food

EosophagusEosophagus Consists of four layersConsists of four layers Lining epithelium is stratified Lining epithelium is stratified

squamous non-keratinizedsquamous non-keratinized Eosophageal submucus glandEosophageal submucus gland Eosopageal cardiac glandsEosopageal cardiac glands Muscular layerMuscular layer Covering serosa and adventitiaCovering serosa and adventitia Parts of the esophagusParts of the esophagus

Upper partUpper part

Middle partMiddle part

Lower partLower part

esophagusesophagus

The histological The histological structure of the structure of the esophagusesophagus The mucosa: the epithelium formed of stratified The mucosa: the epithelium formed of stratified

squamuse non keratinized epithelium this epithelium squamuse non keratinized epithelium this epithelium rich in mucus cellsrich in mucus cells

The lamina proporia: formed of collagen fibers rich in The lamina proporia: formed of collagen fibers rich in blood vessels support the mucosa to the sub mucosablood vessels support the mucosa to the sub mucosa

The muscularis mucosa: formed of smooth muscle it is The muscularis mucosa: formed of smooth muscle it is function conduction of the gland secretion function conduction of the gland secretion

The sub mucosa: formed of areolar tissue contain The sub mucosa: formed of areolar tissue contain blood vessels, lymphatic, and nerve fibersblood vessels, lymphatic, and nerve fibers

The musculosa: formed of two layers of smooth The musculosa: formed of two layers of smooth muscle inner circular and outer longitudinal muscle inner circular and outer longitudinal

The serosa: formed of deep fascia in the neck and he The serosa: formed of deep fascia in the neck and he chest but by mesothelium in the abdomen chest but by mesothelium in the abdomen

Esophagus (cross Esophagus (cross sectionsection((

The stomachThe stomach

Definition: it is the most dilated part of the Definition: it is the most dilated part of the G.I.T. organsG.I.T. organs

It is function is the digestion of food by It is function is the digestion of food by two methodstwo methods

Mechanical digestion: by the thick wall of Mechanical digestion: by the thick wall of the stomachthe stomach

Chemical digestion: by the secretion of Chemical digestion: by the secretion of enzymes enzymes

Parts of stomachParts of stomach

The stomach formed of four parts:The stomach formed of four parts: The cardiacThe cardiac The fundsThe funds The bodyThe body The pyloricThe pyloric

The stomachThe stomach

The histological The histological structure of the structure of the stomachstomach

The mucosa: the epithelium formed of simple The mucosa: the epithelium formed of simple columnar ciliated epithelium. It is folded and formed columnar ciliated epithelium. It is folded and formed the gastric glands which open in the surface by the gastric glands which open in the surface by gastric pitsgastric pits

The types of epithelial cellsThe types of epithelial cells The mucus cells: it is function secretion of mucusThe mucus cells: it is function secretion of mucus The parietal cells: it is function secretion of HCLThe parietal cells: it is function secretion of HCL The peptic cell: it is function secretion of pepsinThe peptic cell: it is function secretion of pepsin The stem cell : it is function divided and gives other The stem cell : it is function divided and gives other

types of cells types of cells

The lamina proporiaThe lamina proporia

It is formed of collagen fibers and it rich It is formed of collagen fibers and it rich in blood vessels, nerve fibers in blood vessels, nerve fibers

It is function to support the mucosaIt is function to support the mucosa The musularis mucosa: it is formed of The musularis mucosa: it is formed of

sheet of smooth muscle it is function is sheet of smooth muscle it is function is the conduction of the gastric secretion the conduction of the gastric secretion

The sub mucosaThe sub mucosa

It is formed of loose connective tissue It is formed of loose connective tissue which contain blood vessel , nerve fibers, which contain blood vessel , nerve fibers, and lymphatic tissueand lymphatic tissue

The nerve fibers formed plexuses which The nerve fibers formed plexuses which is called the missioner's plexusesis called the missioner's plexuses

The musculosaThe musculosa

It is thick and formed of three layersIt is thick and formed of three layers Inner obliqueInner oblique Middle circularMiddle circular Outer longitudinalOuter longitudinal

Histological structure Histological structure of stomachof stomach

The serosaThe serosa

It is formed of mesothelium It is formed of mesothelium (simple squamuse epithelium) of the (simple squamuse epithelium) of the inner layer of the peritoneum inner layer of the peritoneum

The different between The different between the parts of the the parts of the stomachstomach

All the parts of stomach have the same All the parts of stomach have the same histological structure except in the histological structure except in the following:following:

The pyloric part has branches gastric The pyloric part has branches gastric glands and wide gastric pitsglands and wide gastric pits

The funds and the body have rich The funds and the body have rich parietal cells than the pyloricparietal cells than the pyloric

The pyloric has much mucus cells The pyloric has much mucus cells

The small intestineThe small intestine

The small intestine formed of three partsThe small intestine formed of three parts The duodenumThe duodenum The jejunumThe jejunum The ileum The ileum

The duodenumThe duodenum

It is the first part of the small intestine It is the first part of the small intestine extend from the stomach to the jejunumextend from the stomach to the jejunum

The function of the duodenum The function of the duodenum Neutralization of the gastric acidityNeutralization of the gastric acidity Continues the process of digestionContinues the process of digestion Absorption of nutrient materials Absorption of nutrient materials

The histological The histological structure of the structure of the duodenumduodenum The mucosa: the epithelium formed of The mucosa: the epithelium formed of

simple columnar ciliated epithelium it simple columnar ciliated epithelium it forms finger like projection called the villi forms finger like projection called the villi the spaces between them called crypts the spaces between them called crypts

The lamina proporia: collagen fibers to The lamina proporia: collagen fibers to support the mucosasupport the mucosa

Muscularis mucosa: smooth muscle and Muscularis mucosa: smooth muscle and extend deep in the villiextend deep in the villi

The sub mucosaThe sub mucosa

It is formed of loose connective tissue it It is formed of loose connective tissue it contain blood vessels, nerve fibers and contain blood vessels, nerve fibers and lymphatic tissue also it contain serious lymphatic tissue also it contain serious glandsglands

The musculosa: formed of tow layers of The musculosa: formed of tow layers of smooth muscles inner circular and outer smooth muscles inner circular and outer longitudinallongitudinal

The serosa: formed of mesothelium The serosa: formed of mesothelium

The duodenumThe duodenum

The jejunum and ileumThe jejunum and ileum

The jejunum formed the upper part of the The jejunum formed the upper part of the small intestine while the ileum formed the small intestine while the ileum formed the lower part lower part

The function of the jejunum and ileum The function of the jejunum and ileum absorption of nutrient substanceabsorption of nutrient substance

The histological The histological structure of the structure of the jejunum and ileumjejunum and ileum

The jejunum has the same histological The jejunum has the same histological structure of the duodenum but the structure of the duodenum but the lymphatic tissues in the sub mucosa lymphatic tissues in the sub mucosa increased and formed aggregations of increased and formed aggregations of lymph called peyer,s patches and the villi lymph called peyer,s patches and the villi become longerbecome longer

The ileum has the same histological The ileum has the same histological structure but the lymph and the mucus structure but the lymph and the mucus cells increased cells increased

The large intestineThe large intestine

The large intestine formed of the The large intestine formed of the following organs:following organs:

The cecaumThe cecaum The colonThe colon The rectumThe rectum The anal canalThe anal canal

The function of the The function of the large intestinelarge intestine

The absorption of waterThe absorption of water Excluded of the waste productExcluded of the waste product

The histological The histological structure of the large structure of the large intestineintestine

TheThe mucosamucosa: the epithelium formed of : the epithelium formed of simple columnar ciliated epithelium which simple columnar ciliated epithelium which is folded and formed straight glandsis folded and formed straight glands

the epithelium cell formed of two types the epithelium cell formed of two types mucus cellsmucus cells for secretion of mucus and for secretion of mucus and brush cellsbrush cells for absorption of water the for absorption of water the mucus cells increas and the brush cells mucus cells increas and the brush cells decrease toward the anal canal decrease toward the anal canal

The lamina proporiaThe lamina proporia It formed of collagen fibers rich in blood vessels and It formed of collagen fibers rich in blood vessels and

peyer,s patchespeyer,s patches TheThe muscularismuscularis mucosamucosa: formed of sheet of smooth : formed of sheet of smooth

muscle it is function the conduction of the gland muscle it is function the conduction of the gland secretionsecretion

TheThe subsub mucosamucosa: formed of loose areolar tissue : formed of loose areolar tissue contain blood vessel, nerve fibers, and lymphatic contain blood vessel, nerve fibers, and lymphatic tissue tissue

The musculosaThe musculosa: formed of two layers of smooth : formed of two layers of smooth muscle inner circular and outer longitudinal. The muscle inner circular and outer longitudinal. The longitudinal muscle collected into bands called tena longitudinal muscle collected into bands called tena colli colli

The serosaThe serosa: formed of mesothelium : formed of mesothelium

Large intestine Large intestine (cross section(cross section((

The anal canalThe anal canal

DefinitionDefinition: it is the lower part of the large : it is the lower part of the large intestineintestine

It is function to give passage for the It is function to give passage for the feces out side the body feces out side the body

The histological structure The histological structure of the anal canalof the anal canal

The mucosaThe mucosa: the upper part of the anal canal : the upper part of the anal canal lined by simple columnar while the middle part lined by simple columnar while the middle part lined by stratified squamus non keratinized lined by stratified squamus non keratinized epithelium and the lower part lined by skinepithelium and the lower part lined by skin

The mucosa fold and formed the anal columnsThe mucosa fold and formed the anal columns The lamina proporiaThe lamina proporia: formed of collagen : formed of collagen

fibers support the mucosa fibers support the mucosa The sub mucosaThe sub mucosa: it is formed of loose tissue : it is formed of loose tissue

contain blood vessel, nerve fibers and contain blood vessel, nerve fibers and lymphatic lymphatic

The musculosaThe musculosa

It is formed of inner circular layer which is It is formed of inner circular layer which is thick at the lower part and outer thick at the lower part and outer longitudinal layer. There is skeletal longitudinal layer. There is skeletal muscles cover the outer longitudinal muscles cover the outer longitudinal layerlayer

The serosaThe serosa: formed of connective tissue : formed of connective tissue to support the anal canal with the to support the anal canal with the surrounded tissue surrounded tissue

Anal canalAnal canal

The liverThe liver DefinitionDefinition : the liver is the largest gland in : the liver is the largest gland in

the body it is located in the right side of the the body it is located in the right side of the abdomenabdomen

The functions of the liverThe functions of the liver:: Detoxification of metabolic waste productDetoxification of metabolic waste product Destruction of the span red blood cellsDestruction of the span red blood cells Syntheses of the bileSyntheses of the bile Syntheses of the plasma proteinsSyntheses of the plasma proteins Metabolic functions Metabolic functions

The liver functionsThe liver functions The blood reach the liver through the portal vein The blood reach the liver through the portal vein

which is carry non oxygenated blood from intestine which is carry non oxygenated blood from intestine .and the hepatic artery which carry oxygenated .and the hepatic artery which carry oxygenated blood.blood.

These vessels divided and finally reach the angles These vessels divided and finally reach the angles of the hepatic lobule, then the blood passes in the of the hepatic lobule, then the blood passes in the sinusoid where the hepatic cells perform there sinusoid where the hepatic cells perform there function and drainage in the central vein.function and drainage in the central vein.

The bile secreted by the hepatic cells in the bile The bile secreted by the hepatic cells in the bile canals where it collect in the bile ductcanals where it collect in the bile duct

The hepatic cells: they are cubical in shape. It is The hepatic cells: they are cubical in shape. It is double nucleated cells active cells double nucleated cells active cells

Shape of the liverShape of the liver

Histological structure Histological structure of the liverof the liver

The liver is formed of The liver is formed of StromaStroma: which is the capsule that covered the : which is the capsule that covered the

liver and fixed and protect it. It is formed of liver and fixed and protect it. It is formed of collagen fiberscollagen fibers

The parenchymaThe parenchyma: which is tissue of the liver it : which is tissue of the liver it is formed of the hepatocytes and blood is formed of the hepatocytes and blood sinusoid and bile canaliculisinusoid and bile canaliculi

The hepatocytes arranged into rows and The hepatocytes arranged into rows and formed hexunal shape called hepatic lobule formed hexunal shape called hepatic lobule

Cross section (liver(

The hepatic lobuleThe hepatic lobule Definition:Definition: it is the functional unite of the it is the functional unite of the

liver. It is hexanal shapeliver. It is hexanal shape It is formed of six angles in each one It is formed of six angles in each one

contain branch of portal vein, hepatic artery, contain branch of portal vein, hepatic artery, and bile duct. In the center it contain central and bile duct. In the center it contain central vein.vein.

Between the center and the angle the Between the center and the angle the hepatic cells arranged into rows which are hepatic cells arranged into rows which are separated by blood sinusoid. In the middle separated by blood sinusoid. In the middle of each row there is bile canal of each row there is bile canal

Hepatic lobuleHepatic lobule

The pancreasThe pancreas

Definition: it is lobulated mixed gland Definition: it is lobulated mixed gland located at the concavity of the duodenumlocated at the concavity of the duodenum

The pancreas has exocrine secretion for The pancreas has exocrine secretion for the digestion of the carbohydrate and it is the digestion of the carbohydrate and it is endocrine secretion for control of the endocrine secretion for control of the blood glucose blood glucose

pancreaspancreas

The histological structure The histological structure of the pancreasof the pancreas

The pancreas enclosed by thin capsule formed of The pancreas enclosed by thin capsule formed of collagen fibers. From the capsule thin septa collagen fibers. From the capsule thin septa descend and divided the parenchyma into lobes descend and divided the parenchyma into lobes

The parenchyma formed of tubules surrounded by The parenchyma formed of tubules surrounded by cells these tubules called the pancreatic acini . The cells these tubules called the pancreatic acini . The pancreatic acini drainage at the main pancreatic pancreatic acini drainage at the main pancreatic duct which open at the duodenumduct which open at the duodenum

Between the pancreatic acini there is dark cells Between the pancreatic acini there is dark cells which are the endocrine cells of the pancreas called which are the endocrine cells of the pancreas called islet of langerhanes islet of langerhanes

Histological structure of Histological structure of pancreaspancreas