Disorders of Hepatobiliary and Exocrine Pancreas Function Flashcards
Understand blood flow to the liver and implications with portal hypertension
liver is unique among the abdominal organs in having a dual blood supply consisting of venous (portal) supply through the hepatic portal vein and an arterial supply through the hepatic artery.
a major exocrine function of the liver is bile secretion. the intrahepatic and extrahepatic bile ducts often are collectively referred to as the hepatobilliary tree.
the pancreatic duct joins the common duct at a short dilated tube called the hepatopancreatic ampulla (ampulla of Vater) which empties into the duodenum
Outline basic functions of the liver, pancreas and biliary system
liver cells have the ability to store large amounts of glucose as glycogen through a process called glycogenesis. when blood glucose levels are low, glycogen is converted back to glucose through glycogenolysis.
liver is an important site for protein synthesis and degradation - albumin.
all urea formed in the body is synthesized by the urea cycle in the liver and then excreted by the kidneys.
in advanced liver disease, urea synthesis often impaired, leading to an accumulation of blood ammonia
Understand the formation and excretion of bilirubin
bilirubin is the final product of the breakdown of heme contained in aged red blood cells. bilirubin is the substance that gives bile its color.
unconjugated bilirubin, which is insoluble in plasma, is transported in the blood attached to plasma albumin. as it passes through the liver, unconjugated bilirubin is absorbed through the hepatocytes’ cell membrane. unconjugated bilirubin is converted to conjugated bilirubin, making it soluble in bile. conjugated bilirubin is secreted as a constituent of bile, and in this form it passes through the bile ducts into the small intestine.
Define cholestasis; steatosis; hypersplenism; cholelithiasis; cholecystitis; cholangitis and choledocholithiasis and relation to disease processes
the secretion of bile is essential for digestion of dietary fats and absorption of fats and fat-soluble vitamins from the intestine.
common to all types of obstructive and hepatocellular cholestasis is the accumulation of bile pigment in the liver.
Cholestasis: decrease in bile flow through the intrahepatic canaliculi and a reduction in secretion of water, bilirubin, and bile acids by hepatocytes.
steatosis: fatty liver is characterized by the accumulation of fat in hepatocytes (fatty liver)
hypersplenism: the enlarged spleen often gives rise to sequestering of significant numbers of blood elements and development of syndrome hypersplenism.
cholelithias: gallstones
cholecystitis: inflammation of gallbladder
choledocholithiasis: gallstones
Understand cirrhosis of the liver
end-stage chronic liver disease, much of the functional liver tissue has been replaced by fibrous tissue.
hepatomegaly and jaundice are also common signs of cirrhosis.
late manifestations of cirrhosis are related to portal hypertension and liver cell failure.
Know etiology and manifestations of portal hypertension
portal hypertension is characterized by increased resistance to flow in the portal venous system and sustained portal vein pressure.
major complications of increased portal vein pressure and the opening of collateral channels are ascites, splenomegaly, hepatic encephalopathy, and formation of portosystemic shunts with bleeding from esophageal varices.
spontaneous bacterial peritonitis - infection
enlarged spleen often gives rise to sequestering of significant numbers of blood elements and development of a syndrome known as hypersplenism.
with the gradual obstruction of venous blood flow in the liver, pressure in the portal vein increases, and large collateral channels develop between the portal and systemic veins.
Recognize manifestations of liver failure
disorders of synthesis and storage functions:
glucose - hypoglycemic events
proteins - hypo-albuminemia (edema/ascites), decreased coagulation factors (bleeding)
lipoprotein cholesterol - decreased cholesterol
bile salts - impaired fat absorption (deficiency of fat-soluble vitamins, fatty stools)
disorders of metabolic and excretory functions:
amino acids - impaired conversion of ammonia to urea (encephalopathy)
steroid hormones - increased aldosterone (edema/ascites), increased androgens/estrogens (gynecomastia & testicular atrophy in men; menstrual irregularities in women)
drugs - drug interactions and toxicities
bilirubin - hyperbilirubinemia (jaundice)
Understand and explain hepatobiliary duct system
gallbladder: distensible, pear-shaped, muscular sac located on the ventral surface of liver. function - store & concentrate bile.
left and right hepatic ducts come together to form the common hepatic duct.
cystic duct extends to the gall badder.
common bile duct formed by the union of the common hepatic duct and cystic duct.
cholecystokinin provides strong stimulus for gallbladder contraction.
pressure in common duct largely is responsible for regulating passage of bile into the intestine.
Know common etiologies of acute pancreatitis and two common risk factors for pancreatic cancer
gallstones (stones in the common duct), alcohol abuse, hyperlipidemia, hyperparathyroidism, infections (particularly viral), abdominal and surgical trauma, drugs such as steroids and thiazide diuretics
acute pancreatitis represents a reversible inflammatory process of pancreatic acini brought about by premature activation of pancreatic enzymes.
the pathogenesis of acute pancreatitis involves autodigestion of pancreatic tissue by inappropriately activated pancreatic enzymes.
although a number of factors are associated with the development of acute pancreatitis, most cases result from gallstones (stones in the common duct) or alcohol abuse.
abdominal pain = cardinal manifestation of acute pancreatitis.
