Download The Stomach Is a structure that receives food from esophagus

The Stomach
Is a structure that receives food from esophagus & delivers its contents(Chyme)into
the Duodenum.It is the most dilated & distensable part of the G.I.T,is situated in the
epigastric,umbilical & left hypochondriac regions of the abdomen extending
between the Gastroesophageal junction(Cardia) to the Gastroduodenal
junction(Pylorus).It is jar shaped or resemble the letter J ,it has 2 surfaces(anterior
&posterior),2 orifices(Cardia & Pylorus), 2 borders ( lesser & greater curvatures)& its
capacity ranges 1300-1700 (average 1500) ml in the adults.The 2 borders
(curvatures) are the lesser curvature& greater curvatures.The lesser curvatures
extends from the right side of the esophageal end to the pylorus,we can see incisura
angularis( a notch) on this border& lesser omentum( ligament) is attached along this
border connecting the lesser curvature of the stomach to the porta hepatis of the
liver( it includes 2 smaller named ligaments ;Gastrohepatic&Gastroduodenal ).It
contains many structures between the 2 paritoneal layers these are the followings:
1-Left gastric artery
2-Right gastric artery
3-Hepatic artery
4-Portal vein
5-Bile duct
6-Autonomic nerve fibers from Celiac plexus
7-lymph nodes & lymphatic vessels
The greater curvature is convex & directed to the left side,it extends from the left
side of the Cardia to the right side to reach the pyloric end.At its beginning there is a
a depression ( Cardiac incisura),there is also gastrosplenic ligament connecting the
fundic region to the spleen.The greater omentum is an important peritoneal
ligament for the storage of fat & can limit the spread of infection in the peritoneal
cavity,it contains the following structures:
1-Left Gastroepiploic artery
2-Right Gastroepiploic artery
3-Autonomic nerve fibers
4-Lymph nodes & lymphatic vessels
The peritoneum: Is a thin serous membrane consists of 2 layers ;outer parietal layer
lyning the inner surface of the abdominal wall(receives somatic innervation ) &
visceral layer(is the reflected part ofparietal peritoneum)it covers the Viscera(is
supplied by autonomic nerves & thus it is insensitive to painfull stimuli).There is
lumbricating serous fluid between the 2 layers (peritoneal cavity or Greater Sac).The
peritoneum gives rise to some ligaments( peritoneal folds)as greater & lesser
Omentum;Gastrosplenic,Phrenicocolic;Leinorenal& Mesentries(this connects the
intestine to posterior abdominal wall &transmits blood & nerves supply to the
intestine also contains some lymphatic vessels & nodes +veins).The short peritoneal
folds form small spaces( Recesses)in relation to some organs & might invite internal
hernia of trapped intestine or omentum as Duodenal & Ileocaecal recesses.
The stomach is completely surrounded by peritoneal coverings from its anterior
&posterior surfaces (Intraperitoneal structure)where the 2 layers of lesser omentum
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separates at the lesser ,the anterior layer will cover the anterior surface of stomach
,while the posterior layer covers the posterior surface of the stomach.Then the 2
layers meet again at greater curvature forming the greater omentum .This connects
greater curvature with the transverse colon as Gastrocolic ligament,which then
descends downward from the transverse colon like an Apron in front of the c
entrally placed coils of small intestine.
During development of the stomach &its rotation to 90 degree part of the general
tomach,infront of upper part of posterior abdominal wall ( What is called stomach
bed),with the lesser omentum in front & part of the greater omentum >This space is
known as Lesser Sac or OMENTAL BURSA.It communicates with the greater sac (
general peritoneal cavity) by an opening known as the Epiploic foramen,which is
bounded by the following structures:
1-Anteriorly by the free border of lesser omentum with the hepatic A,bile duct&
portal vein in the free border of lesser omentum
2-Posteriorly by the inferior vena cava
3-Superiorly by the caudate process of caudate lobe of the liver
4-Inferiorly by the first part of the Duodenum
The pyloric region is marked on the surface of the stomach by pyloric constriction
indicating the position of the Pyloric Sphincter.The prepyloric vein crosses anteriorly
on this surface.The pylorus is located at about 1.25 cm to the right of the mid line at
the level of the Transpyloric plane( passes at level of lower border of L1 vertebra.
The Stomach Bed (The floor of lesser sac) contains the following structures:
1-Left Dome of Diaphragm
2-Left suprarenal(Adrenal) gland
3-The upper part of the left kidney
4-The Body of the Pancreas
5-Transverse Mesocolon(its linear attachment to anterio aspect of pancreas
6-Slenic artery running on the superior surface of pancreas
7-Left colic flexure(Splenic flexure)
The Stomach has the following parts:
A-The fundus,it is the convex part of the stomach to the left & above the level of the
Cardiac orifice of the stomach.It is related to the left cupula of the Diaphragm&
being connected to the spleen by the Gastrosplenic ligament & is usually contains
gasses(Air bubble ).It is supplied by short gastric branches from Splenic artery
B-The body ,which extends between the Cardia & Pylorus having the lesser &
creater curvatures .The R&L gastric arteries run along its lesser curvature at the site
between the attachment of the 2 layers of the lesser & greater omentum on to the
lesser & greater curvatures respectively.The anterior surface is related anterior
abdominal wall (from inside) at the epigastric & umbilical regions,while its posterior
surface is in fact the anterior wall of the Omental Bursa(lesser sac).The body is
completely peritonealized(intraperitoneal structure)& is freely movable to mix food
reaces it with the gastric secretions.At its junction with the pyloric antrum there is
what is called Incisura Angularis(on its posterior aspect we can see the prepyloric
vein) & the body is supplied by branches from R& L gastric arteries on the side of
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lesser curvature ,and branches of R&L gastroepiploic arteries on the side of greater
curvature.The body usually lies horizontally across the abdominal cavity.
C-Pylorus consists of pyloric antrum & pyloric canal .The canal is the narrowest part
of the pyloric region & leads to the duodenum (Gastroduodenal junction) by the
pyloric sphincter which is formed by the concentric layers of circularly arranged
smooth muscles at this area ,it regulate the emptying times of the stomach.The
stomach has rich arterial blood supply by the branches of Celiac trunk (R&l
gastric;R&L gastroepiploic = short gastric branches from the splenic artery).Its
innervation is by Autonomic by plexuses of fibers coming from the 2
vagi(parasympathetic) and sympathetic fibers coming from greater splanchnic
nerve after synapsing in the celiac ganglion.Its lymphatic as follows:
1-Pancreatico-splenic nodes lying along the course of the splenic artery.
2-The left gastric nodes drains into the Celiac nodes
3-The right gastroepiploic drains into the nodes at the angle between 1st & 2nd parts
of the Duodenum.
4-Pyloric,hepatic & left gastric nodes drain to the Celiac nodes.
The Small Intestine
Is the longest part of the alimentary tract.It measures about 6.5(6-7)gastroduodenal junction superiorly to the Ileo-caecal valve inferiorly .It includes 3 parts
namely :the Duodenum (about 25 cm in length);Jejunum about two fifth of the
length of small intestine( nearly 2.5 meters),it is a coiled part ;Ileum which form
three fifth of the small intestine (around 3.5 meters).The Duodenum is a
retroperitoneal structure (fixed part)except half of the first part which is movable
with the stomach (intraperitoneal part);the jejunum & ileum are attached to the
posterior abdominal wall by Dorsal Mesentry(It is movable).The mesentry is very
short at the site of the posterior abdominal wall,where it is attached,here its length
is about 15 cm,while its periphery(at the intestinal border ) it is about 6 meters(the
same length of the small intestine.The attachment of the root of Dorsal Mesentry
extends from Duodeno-jejunal flexure(to the left of L2 vertebra)to the Right Sacroiliac joint,while the free border covers the jejunum & ileum(contains blood
vessels,nerves& lymphatics).
The main differences between jejunum & ileum are the followings:
1-The jejunum is the upper & the left part of the of intestinal area;where as the
ileum is lower & to the right of the intestinal area.
2-Jejunum is thicker & more vascular than the ileum.
3-The lumen of jejunum is wider(4 cm) ;while the ileum is narrower(3 cm).
4-The mesentry of jejunum is transpart(less fatty content)& vasa recti are less (1-2
arcades with taller terminal ends0in the jejunum;while in the ileum more fat (
mesentry opaque)and has more arterial arcades(5-6)with shorter terminals
5-The jejunum has larger & more circular mucosa with pyers patches(lymphoid
follicles);while in the ileum are smaller & spares with little or absent lymphoid
follicles in the ileal mucosa.
The coiles of the small intestine are centrally placed within the frame formed by the
large intestine.The jejunum & ileum are supplied by branches from superior
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mesenteric artery& venous blood drains to the superior mesenteric which direct it to
the liver via the portal vein& nerve supply by perivascular autonomic.
THE DUODENUM
Is the first part of the small intestine,is about 10-12 inches(about 25 cm) length.It
start on the right side of L1 vertebra (from pylorus( & it curves around the head of
the pancreas in form of C shaped structure.It is a retroperitoneal structure(covers
by peritoneum only on its anterior surface) i.e fixed,except the proximal one inch (
near the pylorus) which is peritonealized as that of the stomach(intraperitoneal) and
movable with the stomach.It divides into 4 parts:
A-First part (about 5 cm),starts from Duodenopyloric junction ,ascends from the
pylorus just on the right side of L1 vertebra,part of it is completely peritonealized
&movable with stomach ,while the other is retroperitoneal fixed part.The first part is
connected with the porta hepatis by Hepatoduodenal ligament,posterior to the first
part runs the portal vein & bile duct,while its anterior surface is related to the neck
of the Gall bladder,inferior to it is the upper surface of head of pancreas.
B- Second part ( Descending part),is about 7-8 cm in length& is the most important
part of the Duodenum as it receives the bile(from liver)& pancreatic juice of the
exocrine part of the pancreas at its medial surface where the 2 ducts meet & unite
forming Hepatopancreatic Ampulla(of Vater)which pierces the mucosa of Duodenum
& opens at the summit of Major Duodenal Papilla,while the accessory pancreatic
duct ,which drains part of head of Pancreas opens into the Minor duodenal
papilla.Medially this part is related to head of pancreas,posteriorly it lies on the
hilum of the right kidney.It descends from level of L2 to lower border of L3 vertebra.
C-The third part ( Horizontal part)passes to the left side crossing the right
ureter,I.V.C & abdominal aorta(posterior relations),while anteriorly it is crossed by
the root of the mesentry& superior mesenteric artery.At the upper border of it the
superior mesenteric artery arised from aorta ,while at lower border of it arised the
inferior mesenteric artery.Superior to it is the head of the pancreas.It is about 9.510-5 cm in length.
D-The forth part(the shortest 2-3 cm),it ascends on the left side of the abdominal
aorta to the level of the upper border of L2 vertebra,where it continues into the
Jejunum at the Duodenojejunal flexure.
Blood supply: The duodenum receives its blood supply by branches from
Gastroduodenal,superior & inferior pancreaticoduodenal arteries & by
retrodudenal( from splenic artery),its venous drainage is by the corresponding veins
which leads into the portal vein.
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The Large Intestine ( Colon)
It is about 1.5 meter in length( about one fourth that of small intestine),its main
function is to absorb fluids & solutes.it start at the right iliac fossa as the Caecum
(most dilated part of colon) which receives the terminal part of the small intestine at
Ileo-Caecal junction (guarded by 2 lips of the ileocaecal valve)the terminal part has
intramural entrance through the wall of the Caecum,the caecum also shows a worm
like structure mostly on its posterior aspect known as Appendix usually as
retrocaecal in position.The caecum continues up as the Ascending colon(15 cm)till
the level of the liver(Hepatic flexure or right colic flexure),then continues to the left
a cross the abdominal cavity as a transverse colon (50 cm)which ends beside the
spleen (Splenic flexure or left colic flexure)which continues downward on the left
side as Descending colon (25 cm) till the left iliac fossa & brim of the pelvis ,it enters
the lesser (true)pelvis as an S shaped structure known as Sigmoid colon (40 cm) till
the level of S3 vertebra where it continues down ward as Rectum(12-15 cm),then
just below the tip of Coccyx it continues downward & back ward as Anal canal(4-5
cm) which opens to the exterior at the Anus.All parts of the large intestine are fixed
except the transverse & sigmoid parts are freely movable part as they have
mesentry (transverse & sigmoid mesocolon) and both of them are lible for twisting
(Volvulus) causing intestinal obstruction which is an emergency requires surgical
intervension(operation).On the lateral side of both the ascending & descending
colons there are para-colic gutters(play a role in movement of fluids & infected
materials ,thus helps to spread the infection leading to peritonitis with its
sequences ,for example perforated duodenal ulcer & subhepatic or subphrenic
abscesses may complicates appendicitis & peritonitis with paralytic ileus.
The Appendix: is about 10 cm(4-20)in length narrow diverticulum from the
posteromedial aspect of caecum ,where it opens into the caecum by a narrow
opening near the ileo-caecal valve.Its position is retrocaecal (behind caecum ) in
about 65% ,pelvic position in 20-30% ( descend below the pelvic brim),subcaecal &
subileal.It's important in animals only & in human being it is of no benefits at all.It
has a short triangular peritoneal fold connecting it to ileum known as
MESOAPPENDIX( for the passage of appendicular artery),the appendicular artery is a
branch from caecal artery(from ileocecal branch of superior mesenteric artery).The
base of the appendix is marked at McBurney's
Point(junction between medial third & lateral two thirds of a line joining anterior
superior iliac spine & umbilicus.
The sigmoid mesocolon coonect the transverse colon to posterior abdominal wall by
linear attachment to the anterior syrface of 2nd part of duodenum &linear
attachment to anterior surface of the pancreas,thus the transverse colon is
intraperitoneal structure.The same thing for the sigmoid colon (intraperitoneal ) and
attached to the posterior wall of the lesser pelvis(true pelvis) by the Sigmoid
Mesocolon..The sigmoid colon continues from the end of the Descending colon
through the pelvic brim to reach the pelvis as one of its contents,it ends & continue
with the rectum at the level of S3 vertebra.It is
Covered by peritoneum &has the Sigmoid mesocolon attaches it to posterior wall of
pelvis.Between the 2 layers of Mesosigmoid run the sigmoidal + superior rectal
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vessels,lymphatic vessels &autonomic nerve fibers.Like wise between the 2 layers of
Transverse mesocolon run the middle colic vessels with its branches,lymphatic
vessels & autonomic nerve fibers.
The differences between Small & Large intestine
1-The large intestine is shorter (1.5 meter)than small intestine(6-7 meter).
2-Large intestine has 3 bands of Taenia coli on its surface,small intestine is not.
3-The large intestine positioned at the sides of abdominal cavity made a frame like
structure surrounding the centrally placed coils of small intestine.
4-The large intestine shows Saculations on their walls,because the colon is longer
than the Taenia coki,while the small intestine lacks any Saculation.
5-Small fat projections(Appendices epiploica)are present on the wall of the colon
(Except the Caecum & Rectum),but small intestine lack them.
6-Colon has bigger caliber ( lumen) than that of the small intestine.
THE PANCREAS & LIVER
They are accessory structures related to the gastrointestinal tract,the pancreas is
closely related to the C shaped structure ,the Duodenum,where as the liver is
considered as the largest organ in the body ,forms about 1.5 kg in weight ( about 2%
of total body weight).
The pancreas:It is a soft lobulated structure lying a cross the a cross the upper
posterior abdominal wall as a retroperitoneal structure ,extending from the C
shaped concavity of the duodenum (on the right side)to the hilum of the spleen(on
the left side).It measures about 15 cm in length,its mainly an exocrine gland
associated with the gastrointestinal gland(delivers its pancreatic juice to 2nd part of
duodenum)& partly an Endocrine gland(ductless as dispersed minute islands
concentrated in the tail ,sending its Hormones to the blood directly).It consists of
Head,Neck,Body & Tail.
The Head;Is a relatively wide enough to fill the concavity of the Duodenum,from its
lower part project a small piece known as Uncinate process (enclosed between the
superior mesenteric artery & upper border of the duodenum.between the head & C
shaped duodenum ,there is a gap through which run the 2 arteries ,the superior
&inferior pancreaticodudenal arteries &anastomosis together here.It is related
superiorly to the 1st part of Duodenum,laterally on the right side to the Descending
part of Duodenum & below is related to the 3rd (Horizontal )part of the Duodenum .
The Neck is the a constricted artery joining the head with the body of the
pancreas,on its anterior surface we can see the Gastroduodenal artery & posterior
to it the portal vein is formed( by union of superior mesenteric & splenic veins).
The Body;Crosses the midline of the abdominal cavity & extends slightly upward &
to the left to approach the spleen,on its upper border runs the splenic artery.It has
3 surfaces;anterosuperior,anteroinferior & posterior surfaces ,thus on cross section
it is triangular in out line.
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The Tail : t runs in the Leinorenal ligament along with the splenic vessels to reach the
Hilum of the spleen.It is rich in Endocrine cells.
The main relations of the Pancreas are:
A-Anterior relation: Transverse colon,the linear attachment of transverse
mesocolon& part of the posterior surface of the stomach.
B-Posterior relation: bile duct,beginning of portal vein,I.V.C Aorta ( with origin of
superior mesenteric A),left kidney& left suprarenal gland&hilum of spleen.
The main duct of the pancreas starts at the tail&runs to the right side within the
substance of the pancreas,it is joined by minute ductules in its course & finally meet
the bile duct forming hepatopancreatic ampula,which pierces the medial border of
the 2nd part of duodenum neat its middle part by intramural course & opens into the
summit of major duodenal papilla.The smaller accessory duct drains the uncinated
process & part of the head of the pancreas & opens into the duodenum by a separate
opening into the Minor duodenal papilla,slightly above the major duodenal papilla.
Blood supply of pancreas is achieved by the following branches:
1-Anterior & posterior superior pancreaticoduodenal from the Gastroduodenal
branch
of the common hepatic (from coeliac trunk).
2-Anterior &posterior inferior pancreaticoduodenal from superior mesenteric artery.
3-Retroduodenal branch from splenic.
4-Dorsal pancreatic from splenic artery.
5-Caudal pancreatic from splenic artery.
6-Arteria magna pancreatica from the splenic artery.
The venous drainage is via the accompanying veins with the arteries & end in portal
V.
The Lymphatic drainage by the following group of lymph nodes:
1-Pancreaticosplenic group of nodes.
2-Pancreaticoduodenal group of nodes.
3-Superior mesenteric group of nodes.
Finally to the Coeliac lymph nodes.
The Liver
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It is reddish brown,soft ,friable &highly vascular.It secretes bile &involved in
carbohydrates,protein &fat metabolism.It is located in the upper part of the
abdomen,immediately below the Diaphragm,
Occupying the right hypochondrium,epigastric region &partially into
The left hypochondrium(protected by lower ribs &their cartilages
Specially the right lobe,but becomes in direct contact with the anterior abdominal
wall in the Epigastric region.It has many surfaces includes superior,right
lateral,anterior,posterior & inferior
(visceral )surfaces.The sharp anterior border separates the anterior from the
visceral(inferior)surfaces&is notched by the teres ligament,
Slightly on the left side of midline.The fundus project about 4-5 cm to the right of the
midline.The ligamentum teres divides the liver into R.&L. lobes,it is completely
peritonealized except a small bare area (on the upper superoposterior aspect)which
become in direct contact with the right dome of the Diaphragm.The porta hepatis is
a horizontal fissure (gives attachment to lesser omentum),it allow the entrance of
portal V & hepatic A to liver & the bile duct to leave the liver.Just at the left end of
porta hepatis the ligamentum teres meets
The ligamentum venosum.Just in front of the porta ,the Quadrate lobe is seen ,while
the caudate lobe &its process is seen just behind the porta.The ligaments of liver are
the followings:
1-Falciform ligament ,it connects the liver to the diaphragm&
Anterior abdominal wall(on the inner surface of the Umbilicus)
2-Ligamentum Teres on the inner free border of the Falciform
Ligament(the remnant of obliterated left umbilical vein)
3-Coronary ligaments,it connects both the superior &posterior surfaces of liver to the
diaphragm,it has 2 layer(anterior &posterior)
Encloses the Bare area of the liver.
4-R&L Triangular ligaments.Represent the meeting of the 2 layers of coronary
ligament laterally on both sides .Each triangular also connect the liver to
diaphragm&its layers continuous with the visceral peritoneum covering thesuperior
and inferior(visceral)
Surfaces.
5-The lesser omentum:Connecting lesser curvature of stomach+
Proximal part of duodenum with the porta hepatis(contains portal V,hepatic A & bile
duct).It includes 2 parts named as Gastrohepatic &Hepatoduodenal ligaments.
6-Ligamentum venosum,represent the remnant of the obliterated
Ductus venosus.
The relations of the visceral surface of liver are:
a-Stomach is related to a big area on the inferior surface of left lobe.
b-Tuber omentale ( elevated area on the right side),behind it is a shallow groove for
the Esophagus..
c-On the right border of Quadrate lobe,there is a fossa for the Gall bladder,where the
gall bladder is situated.The gall bladder fossa is considered as another bare
area,wher the bladder is positioned & a layer of peritoneum fixes the gall bladder in
its fossa(i.e covers the fundic region in situe,thus fixes the gall bladder).
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d-To the right side of gall bladder fossa,there are impressions known as
duodenal,renal(for R kidney) & colic(for R colic flexure).
On the posterior surface of the liver t,where the bare area is seen ,on its base there is
a deep groovefor the I.V.C.Next to the caudate lobe,the lower part of bare area
shows impression for the right suprarenal(Adrenal)gland,
The liver is divided into a big right lobe, small & narrow elongated left lobe,in
addition to caudate & quadrate lobes(the 2 laters are anatomically belong to the
territory of the right lobe.
At the porta hepatis,the 2 hepatic ducts (from R & L lobes) unite to form the common
hepatic duct ,which is about 4 cm in length& descends in the free border of lesser
omentum ,then is joined by cystic duct of the gall bladder to form the bile duct(about
8 cm),
Descends in the lesser omentum,then pass behind the first part of duodenum &head
of the pancreas,then turns medially meeting the main pancreatic duct forming
hepatopancreatic ampulla,which
Pierces the medial aspect of 2nd part of duodenum at its middle
Part &finally opens into the Summit of the Major duodenal papilla,
Which is surrounded by sphincter of Oddi.When food reaches the duodenum,the
duodenal mucosa releases Cholecystokinin which in
Turn stimulate the Gall bladder to contract & sends its bile storage into the 2nd part
of duodenum by the biliary passages.
The sac of Gall bladder is about 30-50 ml in capacity,it lies on the under surface of
the liver in its position in the gall bladder fossa,fixed in situe by a peritoneal layer
passes on the surface of the fundus of the gall bladder.The gall bladder consists of a
fundus,body & neck.The fundus is a rounded part ,seen projecting from the inferior
border & surface of the liver exactly at the tip of the 9th right costal cartilage,the
fundic region is related to the anterior surface of 2nd part of duodenum.The neck is in
contact with the 1st part of duodenum,it is narrow to lead to the cystic duct which
will join the common hepatic duct forming the Bile duct.The body is wide enough &
covers by visceral peritoneum on its anterior surface&its main function is the storage
of the bile until its muscular wall is stimulated by Cholecystokinin released from
duodenal mucosa on contact with the food reaching the duodenum.
The blood supply of the liver is acieved from 2 sources,the hepatic artery(R&L
hepatic)which is a branch of Coeliac trunk&potal vein on
uinter to the corresponding lobes of the liver.The blood from the 2 sources mixes
together in the sinusoids of the liver and then go to the central vein,from here it goes
to the I.V.C via the hepatic veins.
The lymphatic drainage of the liver as follows: from bare area of the liver goes to the
lymph nodes in the thoracic cavity(to posterior mediastinal group of lymph
nodes),while the majority of the liver will go to lymph node group at porta hepatis of
the liver,from here it reaches the Coeliac group of lymph nodes.
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