31.5 Liver and Gallbladder Anatomy Quiz

Liver Anatomy

• The liver is divided into anatomical lobes (left, right, caudate and quadrate) and functional lobes (left and right halves).
• Functional halves are further divided into 8 segments, each with its own biliary drainage and blood supply.
• The portal triad consists of the hepatic artery, hepatic portal vein, and common bile duct.
• The porta hepatis is the entrance to the liver, where the portal triad, lymphatics, and nerves enter.
• Pringle’s Manoeuvre is a surgical technique that involves clamping the hepatoduodenal ligament to control blood flow to the liver.

Gallbladder

• The gallbladder is a pear-shaped structure with a fundus, body, and neck.
• It lies in the gallbladder fossa on the visceral surface of the right lobe of the liver.
• The gallbladder stores and concentrates bile secreted by the liver.
• The cystic duct connects the gallbladder to the common bile duct.
• The common bile duct joins the main pancreatic duct to form the hepatopancreatic ampulla (of Vater), which opens into the duodenum at the major duodenal papilla.
• The sphincter of the ampulla (of Oddi) controls the flow of bile and pancreatic juice into the duodenum.

Venous Drainage

• Blood from the hepatic portal vein and hepatic artery passes through the liver.
• Hepatic veins return blood to the inferior vena cava (IVC).
• The cystic veins drain the neck of the gallbladder directly into the portal vein, while the fundus and body drain directly to the liver (into the hepatic sinusoids).

Porto-Systemic Anastomoses

• These connections allow blood to bypass the liver when portal pressure is increased.
• The para-umbilical veins anastomose with the small epigastric veins, which can result in caput medusae.
• The oesophageal veins (draining into the azygos vein) anastomose with the left gastric vein, which can lead to oesophageal varices.

Nerves

• The hepatic nerve plexus is derived from the coeliac plexus and accompanies the hepatic artery and hepatic portal vein.
• Nerves to the gallbladder pass along the cystic artery from the celiac nerve plexus.
• Cholecystokinin (CCK) stimulates contraction of the gallbladder and bile release.

Clinical Conditions

• Portal hypertension can lead to oesophageal varices and caput medusae.
• Hepatomegaly is an enlarged liver.
• Liver infections, such as abscesses, can be caused by various organisms.
• Liver cancer can be primary or metastatic.
• Trauma to the liver can be managed using Pringle’s Manoeuvre.
• Storage disorders and enzyme deficiencies can affect liver function.
• Cirrhosis is a chronic liver disease with irreversible scarring.

Imaging

• Endoscopic retrograde cholangiopancreatogram (ERCP) is an imaging technique used to visualize the biliary and pancreatic ducts.
• Magnetic resonance cholangiopancreatogram (MRCP) is an imaging technique used to visualize the biliary and pancreatic ducts without using contrast fluid.

Case Study

• A 48-year-old female presents with abdominal pain, fever, chills, nausea, vomiting, and jaundice.
• Imaging reveals signs consistent with cholecystitis (inflammation of the gallbladder) and cholelithiasis (gallstones).
• Gallstones can obstruct the biliary duct system, leading to complications like cholecystitis and pancreatitis.

Lymphatics

• Superficial lymphatics from anterior diaphragmatic and visceral surfaces drain into 3-4 nodes at the porta hepatis (hepatic lymph nodes).
• Hepatic lymph nodes drain into celiac lymph nodes.
• Coeliac lymph nodes drain into cisterna chyli, then to the thoracic duct.
• Superficial lymphatics from the posterior diaphragmatic and visceral surfaces drain to phrenic lymph nodes.
• Phrenic lymph nodes drain to posterior mediastinal lymph nodes, then to the right thoracic duct.
• Gallbladder lymphatics drain to hepatic nodes through a cystic node located at the neck of the gallbladder, finally reaching the coeliac nodes.

Nerves

• Hepatic nerve plexus originates from the coeliac plexus and accompanies the hepatic artery and portal vein.
• Parasympathetic innervation of the hepatic nerve plexus comes from the vagus nerve.
• Nerves to the gallbladder travel alongside the cystic artery from the coeliac nerve plexus.
• Parasympathetic innervation of the gallbladder is from the vagus nerve.

Associated Ligaments

• The liver is attached to the anterior abdominal wall by the falciform ligament.
• The round ligament of the liver (ligamentum teres), located at the free margin of the falciform ligament, is a remnant of the fetal umbilical vein.
• The liver is connected to the stomach by the hepatogastric ligament.
• The liver is attached to the duodenum via the hepatoduodenal ligament.
• The liver is connected to the diaphragm by the right and left triangular ligaments, as well as the anterior and posterior coronary ligaments.

Anatomical Lobes

• The liver is divided into right and left lobes by the falciform ligament.
• The visceral surface of the liver has an H-pattern.
  • The right sagittal fissure is formed by the fossa for the gallbladder and the inferior vena cava (IVC).
  • The left sagittal fissure is created by the fissure for the ligamentum venosum and the fissure for the round ligament (ligamentum teres).
• The caudate lobe is located between the fissure for the ligamentum venosum and the fossa for the IVC.
• The quadrate lobe is situated between the fissure for the ligamentum teres and the fossa for the gallbladder.

Functional Lobes

• The functional lobes divide the liver into left and right halves, further subdivided into eight segments each.
• The eight hepatic (or surgical) segments form independent functional units based on biliary drainage and blood supply.

Porta Hepatis

• The porta hepatis is the main entrance point to the liver and is where the portal triad enters.
• The portal triad consists of:
  • Hepatic artery: Carries oxygenated blood from the systemic circulation.
  • Hepatic portal vein: Carries deoxygenated blood rich in nutrients from the small intestine.
  • Common bile duct: Transports bile from the liver and gallbladder to the duodenum.

Gallbladder

• The fundus of the gallbladder projects onto the lower border of the liver and touches the parietal peritoneum of the anterior abdominal wall at the tip of the ninth costal cartilage.
• Surface landmark of the gallbladder coincides with the intersection of the lateral border of the right rectus abdominis and the costal margin.
  • Murphy's point is located at the level of the transpyloric plane and the right ribcage.
• The gallbladder lies in the gallbladder fossa on the visceral surface of the right lobe of the liver, adjacent to the quadrate lobe.
• It functions in the storage and concentration of bile secreted by the liver, with a capacity of approximately 50mL.

Common Bile Duct

• The common bile duct is formed by the union of the cystic duct from the gallbladder and the common hepatic duct from the liver.
• The common bile duct connects the liver and gallbladder to the duodenum, where it merges with the main pancreatic duct, forming the hepatopancreatic ampulla (of Oddi).
• The hepatopancreatic ampulla is surrounded by the sphincter of Oddi (also called Glisson's sphincter) which controls the flow of bile and pancreatic juice into the duodenum.

Liver Blood Supply

• The liver receives blood from two primary sources:
  • Hepatic artery: Provides oxygenated blood from the systemic circulation.
  • Hepatic portal vein: Delivers deoxygenated blood rich in nutrients from the digestive tract, specifically the small intestine, spleen, and pancreas.
• The hepatic artery branches into the right and left hepatic arteries, each supplying a corresponding hepatic lobe.
• The hepatic portal vein is formed by the union of the splenic vein, superior mesenteric vein, and inferior mesenteric vein.
• Portal hypertension, caused by liver cirrhosis or other conditions that obstruct blood flow to the liver, leads to:
  • Increased pressure in the portal venous system
  • Blood-taking alternative pathways, like the gastroesophageal junction, anus, and anterior abdominal wall to relieve the pressure.
  • Venous enlargement in these areas (varices).

Pringle's Manoeuvre

• Pringle's Manoeuvre involves clamping the hepatoduodenal ligament to temporarily stop blood flow to the liver. This technique is used during surgery to control bleeding and allows for a bloodless field.
• The hepatoduodenal ligament is the free margin of the lesser omentum, which contains the portal triad (hepatic artery, portal vein, and common bile duct).
• The manoeuvre involves clamping the ligament at the epiploic foramen (of Winslow), the entrance to the omental bursa.

Test your knowledge on the anatomy of the liver and gallbladder. This quiz covers the liver's lobes, the portal triad, and the structure and function of the gallbladder. Perfect for students studying human anatomy or healthcare professionals.