Done by: nisreen obeidat

Transcription

1 Sheet: liver and pancreas Done by: nisreen obeidat

2 Embryology of the liver The liver develops in the ventral mesentery of the foregut and divides the ventral mesentery :into 1)lesser omentum (between the liver and the stomach) 2)Falciform ligament (between the liver and the anterior abdominal wall) that has the umbilical vein :Fetal circulation 2 Umbilical arteries (from the fetal aorta) that have deoxygenated blood goes to the placenta then it turns back to the fetal by the left umbilical vein and the returning blood is oxygenated and goes to the fetal liver (won't supply it just passing) then continues its way to the ductus venosus then to the IVC then to the right atrium then the left atrium through foramen oval then to the left ventricle then the aorta and what goes to the right ventricle will be pumped to the pulmonary trunk then to the lungs & aorta through ductus arteriosus Remember: right umbilical vein degenerates in the 5th week After birth: 1)Ductus arteriosus becomes ligamentum arteriosum 2)Thrombosis of the umbilical vein so it becomes fibrous tissue that is called "umbilical ligament or ligamentum teres"

3 Anatomy of the liver **Has a wedge shape and directed downwards & backwards & left **Largest organ in the body, weights 1.5 Kg, located in the right hypochondrial region **The IVC is imbedded in the liver **Has 2 surfaces: visceral (faces the viscera) & diaphragmatic (faces the diaphragm) **The liver is fixed by ligaments that are attached to the anterior abdominal wall & diaphragm **It is divided into 2 main lobes left & right by intralobar fissure Left lobe: small lobe Right lobe: the big lobe; subdivided into smaller lobes which are : Caudate lobe: surrounded by IVC &ligamentum venosus &porta hepatis, and it's connected to right lobe by caudate process Quadrate lobe: surrounded by falciform ligament & porta hepatis & gallbladder **Whole peritoneal covering except one area posteriorly called "BARE AREA" Which is related to the Right suprarenal gland & IVC **Falciform ligament extends superiorly and divides the hypophrenic area into 2 recesses (left & right) and interiorly it's attached with the anterior abdominal wall **There is reflection of the peritoneal to the diaphragm and the result is Right side: upper & lower coronary ligaments meet together and form the right triangular ligament Left side: left triangular ligament

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5 RELATION: Convex Diaphragmatic surface: interiorly >> diaphragm & posteriorly there is bare area and I'd mentioned its relation :Flat Visceral surface 1)Stomach & duodenum 2)Esophagus 3)Lesser omentum 4)Gallbladder 5)Right colic flexure 6)Right kidney & right suprarenal gland gallbladder: its sac composed of (fundus &body & neck) its importance is: 1.Collects bile 2.concentrating bile by water absorption 3.secreting mucous *fundus: bulging below the lower margin of liver *body: fixed to the visceral surface of the liver by the peritoneum so the venous drainage between them is continuous *from neck the cystic duct originates and there is a spiral valve to prevent the bending of the neck and closure of it Left hepatic duct + right hepatic duct = common hepatic duct Common hepatic duct + cystic duct= common bile duct Common bile duct + major pancreatic duct = ampulle of vater opens in the midpoint of 2nd part of the duodenum through major papilla Remember: the free margin of the lesser omentum has 3 tubes: common bile duct >> hepatic artery>>portal vein from out to in **The length of common bile duct: 3 inches (7.5 cm) Inch above the duodenum & inch behind the first part of duodenum (portal vein &gastrodoudenal artery) &inch behind the head of pancreas ** :Blood supply )Hepatic arteries (right & left) = 25% of blood supply (oxygenated blood )Portal circulation =75% of blood supply (deoxygenated blood **Venous drainage: hepatic veins (2-4) then IVC

6 Nerve supply: from celiac plexus sympathetic (greatest splanchnic nerves) & ** )parasympathetic (hepatic branches of the vagus nerve Remember: cranial parasympathetic nerves are 3, 7,9,10 ** :Lymphatic drainage Diaphragmatic surface >> anterior mediastinal lymph nodes Visceral surface >> porta hepatis lymph nodes Inside the liver >> posterior mediastinal lymph nodes OR porta hepatis

7 Histology of the liver The 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 Sinusoids have an incomplete lining of highly fenestrated endothelial cells, some of these cells are macrophagic in function (reticulo-endothelial cells), and 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

8 Histology of Liver

9 Anatomy & histology of pancreas Pancreas 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 An exocrine gland that secretes digestive enzymes and Sodium bicarbonate into the -1 duodenum through the main and accessory pancreatic ducts. Both ducts are usually.interconnected An endocrine gland, which consists of the islets of Langerhans, secretes hormones into.the bloodstream -2 Islets of Langerhans are named for the German physician Paul Langerhans, who first.described them in The normal human pancreas contains about 1,000,000 islets Cells of islets of Langerhans.Beta cells (?-cells), they make about 65-80% of the cells in the islets and produce Insulin-1 alpha cells (?-cells), 15-20%, they produce an opposing hormone, Glucagon which releases -2.glucose from the liver and fatty acids from fat tissue Delta cells (?-cells), 3-10%, they secrete somatostatin a strong inhibitor of somatotropin, -3 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 **Anterior relation : anterior abdominal wall & transverse colon & mesentery of transverse colon & lesser sac & stomach ** Posterior relation Head >> IVC & Neck : portal vein & Body >>splenich vein & splenich artery & lt kidney & lt suprarenal gland & posterior abdominal wall & Tail : hilum of the spleen **Lienorenal ligament : connects between kidney & spleen **Uncinate process: directed to the left; anterior to it there is superior mesenteric artery & superior mesenteric vein

10 Pancreas P AcinIi Pancreas

11 Histology of gall bladder The gall bladder is a simple muscular sac, lined by a simple columnar epithelium. The inner surface of the gall bladder is covered by the mucosa. The sufrace is made up of a simple columnar epithelium. The epithelial cells have microvilli, and look like absorptive cells in the intestine. Underneath the epithelium is the lamina propria. The wall of the bladder does not have a muscularis mucosae and submucosa. The muscularis externa (muscle layer) contains bundles of smooth muscle cells, collagen and elastic fibres. Underneath this, on the outside of the gall bladder is a thick layer of connective tissue, which contains large blood vessels, nerves and a lymphatic network. Where this layer is attached to the liver, it is called the adventia. In the unattached region, there is an outer layer of mesothelium and loose connective tissue (the serosa). Gall bladder