Hepatopancreatobiliary System Email aalnuaimisheffieldacuk E mail abdulameerhyahoocom Prof Abdulameer Al Nuaimi Liver wwwgooglecouksearch Diaphrag Surface Diaph ID: 935846
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Slide1
Embryology of the Hepatopancreatobiliary System
E-mail: a.al-nuaimi@sheffield.ac.ukE. mail: abdulameerh@yahoo.com
Prof. Abdulameer Al-Nuaimi
Slide2Liver
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Diaphrag
. Surface
Diaph
&
V
isc.Surfaces
Visceral
surface
Lt.
Triang
.
Lig
Lt.
lobe
Visceral surface
Quad. lobe
Post Cor.
Lig
Ant.Cor
.
Lig
Bare area
Rt.
Triang
Lig
Rt. Lobe
Gallbladder
Caud
. Lobe
Falciform
Lig
.
Porta
hepatis
Lig
.
Venos
.
Slide3Rt. At,
Rt. Ven.
Aorta
Duct.
Art.
Lt.
Ven.
Internal
Pulm
.
Trunk
Slide4Diaphragm
Bare area of the liver
Reflection of peritoneum
from Liver to DiaphragmReflection of peritoneum
from Liver to the post. Abdominal wall
Post. Abdominal wall
Greater Sac
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Sagittal
Section in the body
Diaphragmatic
surface
Inferior (visceral) surface
Hepatic duct
Ampulla of
Vater
Subphrenic
space
Hepatorenal
space
Slide5Blood Supply of the Liver
The liver receives blood from two sources.1- 25% of the blood supply to the liver is arterial blood from the
hepatic artery (oxygenated).2- 75% of the blood entering the liver is venous blood from the
hepatic portal vein (deoxygenated and containing nutrients).In the liver, the terminal branches of the portal vein and hepatic artery empty together in sinusoids surrounding the hepatic cells. Blood leaves the liver via the hepatic veins which end in the Inferior Vena Cava. This blood is,
deoxygenated, detoxified, and containing normal (homeostatic) nutrient levels.
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Portal system
P.V.
S.V.
S.M.V.
I.M.V
.
Slide7Histology of LiverThe liver is divided into thousands of small units called
lobules by thin layer of connective tissue. Each lobule is about 1mm in diameter and roughly hexagonal in shape. The Lobule is composed of radiating double plates of liver cells (Hepatocytes) separated by a Vascular sinusoidal network.
Each lobule has a central vein in the middle and portal triads at the vertices.
Each portal triad contains branch of hepatic artery, portal vein and Bile duct.
Slide8Liver Lobules
Central Vein
Portal Triad
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Slide9Sinusoids have an incomplete lining of highly fenestrated endothelial cells, some of these cells are
macrophagic In function (reticulo-endothelial cells), they are called
Kupffer cells.The space between endothelium and hepatocytes is called the Space of Disse.
In these spaces, lymph is collected and delivered to lymphatic capillaries. Lymph is collecting in hepatic duct outside the liver.
Blood
from the branches of hepatic artery and portal vein in the Portal triad, drains into sinusoids and
then
to the central vein. Central Veins
carry the
blood
to
hepatic veins which end in the Inferior vena cava
.Bile
is formed by liver cells and is discharged into the bile canaliculi within
layers of the cell plates, and then drains into bile duct of the triads.
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Histology of Liver
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Histology of Liver
Slide12Development of LiverIn the middle of the 3
rd week of pregnancy, the liver bud appears as an endodermal out growth from the distal part of the Foregut (Duodenum). Liver bud proliferates rapidly as an epithelial liver cords and penetrates the ventral mesentery . While hepatic cells are proliferating and penetrating the ventral mesentery, the connection between the liver diverticulum and the duodenum narrows and forming the
Bile Duct.A small ventral outgrowth develops from the bile duct, this new growth forms the Gallbladder and Cystic Duct.
Further growth of liver bud, allows the epithelial liver cords intermingle with the umbilical and vitelline veins. These veins form Hepatic Sinusoids.
Slide13Liver cords differentiates into
Hepatocytes (liver paranchyma) and form the
lining of the biliary ducts.Mesoderm of the ventral mesentery gives rise to
Hematopoietic cells, Kupffer cells and
connective tissue cells.
The Ventral mesentery of the Foregut, is divided by liver into Lesser
Omentum
and
Falciform
Ligament. The liver is clothed by peritoneum except its cranial surface, which is never covered by peritoneum and remains in direct contact with the diaphragm; this area is the
Bare Area of the Liver.
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Budding of Liver
Dorsal Pancreas
Slide15At age of the 10th week
, the liver weight is about 10% of the total body weight. This is due to the presence of large numbers of sinusoids and involvement of the liver in hematopoietic function (production of white and red blood cells).At birth
, the liver weighs about 5% that of the body weight, this is due to the existence of a small number of hematopoietic islands in the liver, and its hematopoietic activity is greatly reduced.Hepatic cells start production of Bile
at age of the 12th week.
Slide16During rotation of the Foregut, the duodenum changes to C-shaped Loop and rotates and swings to the right side of the body. The head of pancreas grows rapidly and fills in the concavity of the C-shaped duodenum.
In this process the right surface of dorsal mesoduodenum fuses with peritoneum lining the posterior abdominal wall, then both layers eventually disappear, and the duodenum and head of pancreas become fixed in a retroperitoneal position to the right side of the midline. As a result of rotation of the duodenum, the entrance of the bile duct in the duodenum is changed from its initial anterior position to a posterior one. Then as a result of swinging and
positional changes of duodenum to the right, the bile duct is shifted behind the duodenum and enters its posteromedial side.
Slide17Development of Liver and Pancreas
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Slide18Development of Duodenum
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Liver bud
Entrance of Co. Bile duct
Liver
Extrahepatic
bile duct
Liver
Co. B. D
Co. B. D
Slide19Liver
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Com. Bile Duct
Slide20The PancreasPancreas is a soft lobulated organ located retroperitoneally across the posterior abdominal wall, it sits behind the stomach across the back of the abdomen.It is described as an organ having head, neck, body, and tail.
The head is disc-shaped and lies within the concavity of the duodenum. Part of the head extends to the left behind the superior mesenteric vessels, it is called Uncinate process.
The body extends to the left side and ends as a tail near the hilus of the spleen.The pancreas is made up of two types of glands, 1-An exocrine gland that secretes digestive enzymes and Sodium bicarbonate into the duodenum through the main and accessory pancreatic ducts. Both ducts are usually interconnected.
Slide212- An endocrine gland, which consists of the
islets of Langerhans, secretes hormones into the bloodstream. Islets of Langerhans are named for the German physician Paul Langerhans, who first described them in
1869. The normal human pancreas contains about 1,000,000 islets. Cells of islets of Langerhans
1-Beta cells (β-cells), they make about 65-80%
of the cells in the islets and produce
Insulin
.
2-
alpha cells (
α
-cells)
, 15-20%, they produce an opposing hormone,
Glucagon which releases glucose from the liver and fatty acids from fat tissue.
3-Delta cells (δ-cells),
3-10%, they secrete somatostatin a strong inhibitor of
somatotropin, insulin, and glucagon; its role in metabolic regulation is not yet clear. Somatostatin is also produced by the hypothalamus and functions to inhibit secretion of growth hormone by the pituitary gland.
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P
Pancreas
Slide23Development of PancreasThe Pancreas develops from the endodermal
lining of the duodenum as a dorsal and ventral buds.The dorsal bud is in the dorsal mesentery and the ventral bud is in the ventral mesentery, close to the bile duct. When the duodenum rotates and become C-shaped, the ventral bud and the entrance of the common bile duct in the duodenum are shifted dorsally.The ventral bud comes to lie immediately below and behind the dorsal bud, finally the parenchyma and duct systems of both buds fuse together. Following swinging of the duodenum to the right, the pancreas and duodenum settles down on the posterior abdominal wall in a retroperitoneal position.
The ventral pancreatic bud forms the
Uncinate process and inferior part of the head of pancreas, where as the dorsal bud forms the
Remaining part of pancreas.
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Slide25Development of Duodenum
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Liver bud
Entrance of Co. Bile duct
Liver
Extrahepatic
bile duct
Liver
Co. B. D
Co. B. D
Slide26Pancreatic ductThe main pancreatic duct is formed by the union of the ventral pancreatic duct with the distal part of the duct of dorsal bud.
The proximal part of the dorsal pancreatic duct, either obliterates or persists to form the Accessory pancreatic duct.The main pancreatic duct, together with common bile duct, enter the Ampulla of Vater which enters the posteromedial wall of the duodenum at the site of
Major Papilla. Accessory pancreatic duct when persist (in 10% of cases), drains the lower part of the head and uncinate process,it
opens into the duodenum at Minor Papilla, 3cm proximal to the opening of the main duct.
Slide27Access.
Panc.Duct
Com. Bile Duct
Minor
Papil
Main
Panc.Duct
.
Access Pan. Duct
Major Papilla
Uncinate Process
Pancreatic duct
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Slide28Pancreatic islets of Langerhans develops from the parenchyma of pancreas at the
third month of fetal life.Insulin secretion begins at the fifth month.
Pancreatic connective tissue develops from the visceral surrounding mesoderm.
Slide29Variations of the opening of common bile duct and pancreatic duct into the duodenum (Contemp
Surg 1987)A- In 85% of cases the common bile duct and pancreatic duct end in the Ampulla of
Vater.B- In 5% of cases, Ampulla of Vater is not present.
C- In 9% of cases, the common bile duct and pancreatic ducts open separately into the duodenum.
85%
5%
9%
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Slide30variations of the third portion of common bile duct to pancreas (Smanio,1954).A, B - The bile duct is partially covered by a tongue of pancreatic tissue
(44%). C- The bile duct is completely covered by pancreatic tissue (30%).D- The duct is uncovered by pancreatic tissue and located on the posterior surface of the pancreas
(16.5%).E- The common bile duct is covered by two tongues of pancreatic tissue (9%).
44%
30%
16.5%
9%
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Posterior surface of the
Head of pancreas and
common bile duct
Slide31SummaryThe liver bud appears as an endodermal out growth from the distal part of the Foregut (Duodenum).
This gives rise to the liver and Extra hepatic biliary passages.During development, rotation and Rt swinging of duodenum, the bile duct entrance in duodenum is shifted from its initial anterior
to a posteromedial position. The Pancreas develops from the endodermal lining of the duodenum as a dorsal and ventral buds. During rotation of duodenum, the ventral bud
is shifted dorsally and fuses with the dorsal bud.islets of Langerhans develops from the parenchyma of pancreas at the third month of fetal life.
Slide32Thank You