GI anatomy Lecture: 6 د. عصام طارق Objectives: To describe the liver. To list main structures in porta hepatis. To define portal system & portosystemic anastomosis. To list parts of biliary system. To relate to portal hypertension & biliary colic.
Largest exocrine, soft dark brown, highly vascular, readily torn. Situated in upper part of abdominal cavity beneath diaphragm under cover of costal margins. It is responsible for: Metabolism of digestive products. Base Storage & release of substances e.g. glucose. The Liver Apex Synthesis, conjugation & transformation of substances e.g. formation of protein & detoxification of poisons.
Surfaces of the liver
Lobes of the Liver Falciform ligament
Left Lobe Right Lobe Porta hepatis Caudate Process
Diaphragmatic surface of liver related to: 1- Lt. Lung & pleura 2- Right Lung & Pleura 4- Xiphoid process 5- Costodiaphragmatic recess 6- Rt. & Lt. costal margins
Visceral surface of the liver
Bare Area of the Liver Omental Tuberosity Right Kidney Stomach Lt. Colic Flexure Groove for Inferior Vena Cava Oesophagus
Peritoneal covering & ligaments of liver Upper layer of Lt. coronary lig. Falciform lig.
Bare areas of the liver Upper & lower layers of Lt. coronary lig. Upper & lower layers of Rt. coronary lig. 5 3 1 Lt. triangular lig. Ligamentum venosum Ligamentum teres 4 2 Rt. triangular lig.
Blood supply of the liver Hepatic artery convey 30% of the blood (oxygenated). The remaining 70% are achieved by portal vein which is rich in products of digestion. Blood is conducted to central vein of each liver lobule The central veins drain into right & left hepatic veins
Lymph drainage of liver Posterior mediastinal lymph nodes Hepatic lymph nodes & celiac Hepatic lymph nodes & celiac
Nerve supply of the liver Anterior vagal trunk Coeliac Plexus
Bile ducts of the liver include: 1- Interlobular ducts in the portal canal 2- Rt. & Lt. hepatic ducts. 3- Common hepatic ducts. 4- Cystic duct. 5- Common bile duct.
Biliary passages Lt. Hepatic duct Rt. hepatic duct Common hepatic duct (4cm long) Cystic duct Common bile duct (8cm long) Main Pancreatic Duct Head of pancreas
Common bile duct 1 st part: free margin of LO 2 nd part: post. to sup. part of duodenum 3 rd part: in a groove on post. surface of pancreas CBD Ampulla of Vater Major duodenal papilla Main pancreatic duct
The Gall Bladder General Features & Peritoneal Covering
Pear shaped sac lies in the fossa for GB Peritoneum Lies in contact binds with body & neck visceral of GB surface to visceral Rounded surface Runs upward, of liver. backward Project below inf. & to left border of liver Totally covered by peritoneum Cystic Artery
Lymph drainage of GB Lymphatics Cystic LN Hepatic LN Celiac LN Nerve supply of GB Achieved by sympathetic & vagal parasympathetic n.f. derived from celiac plexus of nerve.
Portal vein It is 5cm long Begins behind the neck of pancreas It ascends post. to superior part of duodenum in free edge of lesser omentum It drain spleen, pancreas, GB & GIT except lower rectum & anal canal
Sup. Mesenteric vein
Cystic vein Tributaries of portal vein Rt. & Lt. gastric veins a- Short gastric veins Jejunal Inf. Ileal Rt. Ileocolic pancreaticoduodenal Middle Gastroepiploic colic vein Sup. Mesenteric vein b- Left gastroepiploic vein c- Pancreatic veins d- Inferior mesenteric vein Inferior mesenteric vein Sup. rectal Sigmoidal veins Left colic vein
Portosystemic anastomosis portal circulation communicates with the systemic venous circulation at the following situation 1) Lower third of esophagus 2) Rectum 3) At the umbilicus In cases of portal hypertension, these communicating veins may be greatly enlarged & bleeding may occur especially from the distended submucous venous plexuses in the lower esophagus & anal canal.
Biliary colic Inflammation of GB or obstruction of biliary ducts by gallstone. characterized by abdominal colic, pain over right shoulder joint & jaundice. Irritation of subdiaphragmatic parietal peritoneum supplied by phrenic n. C3, 4 & 5 results in a referred pain over shoulder joint. Obstruction of biliary ducts result in backup of bile in ducts & development of jaundice.
Summary: The liver lies in upper part of abdominal cavity under diaphragm It has two surfaces & two main lobes. Receives blood supply from hepatic artery & portal vein Produces bile & deliver it to GIT though the biliary passages Has a pear-shaped sac, GB, lying on its under surface.