Presentation on theme: "CHAPTER 30 DISORDERS OF HEPATOBILIARY AND EXOCRINE PANCREAS FUNCTION Essentials of Pathophysiology."— Presentation transcript:
CHAPTER 30 DISORDERS OF HEPATOBILIARY AND EXOCRINE PANCREAS FUNCTION Essentials of Pathophysiology
PRE LECTURE QUIZ TRUE/FALSE The liver does not play a role in glucose homeostasis. Jaundice results from an abnormally high accumulation of bile in the blood. Hepatitis, inflammation of the liver, is of bacterial origin. Cholelithiasis, or gallstones, is caused by precipitation of substances contained in bile, mainly cholesterol and bilirubin. Chronic pancreatitis is a severe, life-threatening disorder associated with the escape of activated pancreatic enzymes into the pancreas and surrounding tissues. F F F T F
PRE LECTURE QUIZ The __________ cells are capable of removing and phagocytizing old and defective blood cells, bacteria, and other foreign material from the portal blood as it flows through the sinusoid. One of the metabolic functions of the liver is the conversion of ammonia, which is produced by deamination of amino acids, into __________. Pruritus is the most common presenting symptom in persons with cholestasis, probably related to increased bile __________ in the blood. Hepatitis __________ is the most common cause of chronic hepatitis, cirrhosis, and hepatocellular cancer in the world. __________ represents the end stage of chronic liver disease in which much of the functional liver tissue has been replaced by fibrous tissue. C Cirrhosis Kupffer salts urea
LIVER STRUCTURE Blood from hepatic portal vein and hepatic artery mix in sinusoids The sinusoids empty into central veins, which send the blood to the hepatic vein and inferior vena cava
LIVER STRUCTURE(CONT.) Hepatic cells lie along the sinusoids and pick up chemicals from the blood They modify the blood’s composition
LIVER STRUCTUR E(CONT.) At the back end of each hepatic cell, bile is released into a canaliculus The bile is carried to the bile duct and then to the gallbladder
LIVER STRUCTURE (CONT.) Many sinusoids come together to empty into one vein The section of the liver emptying into one vein is a lobule
QUESTION Tell whether the following statement is true or false. The gallbladder stores bile that has been produced by the liver.
ANSWER True Rationale: The liver makes bile and secretes it into the small intestine via the common bile duct. Excess bile is stored in the gallbladder, where it also enters the small intestine through the common bile duct when it is needed.
METABOLIC FUNCTIONS OF THE LIVER Carbohydrate, protein, and lipid metabolism Sugars stored as glycogen, converted to glucose, used to make fats Proteins synthesized from amino acids; ammonia made into urea Fats oxidized for energy, synthesized, packaged into lipoproteins
METABOLIC FUNCTIONS OF THE LIVER (CONT.) Drug and hormone metabolism Biotransformation into water-soluble forms Detoxification or inactivation Bile production
QUESTION Which of the following substances does bile make more susceptible to digestive enzymes? a. Carbohydrate b. Protein c. Fat d. All of the above
ANSWER c. Fat Rationale: Bile (produced in the liver) emulsifies fat molecules so that they are easier to digest. An emulsion is a mixture of two immiscible (unblendable) substances, in this case bile and fat.
SCENARIO Mr. M had a donut for breakfast. Question: Explain how the sugar in the donut left his small intestine and ended up as fat in his carotid artery, giving the: Anatomical structures Chemical processes Hormones that controlled them
SCENARIO Ms. B was prescribed an oral medication for her skin problem. She took it twice a day. The day after she started the medication, Ms. B drank wine with a friend right after taking the prescribed dosage Question: Ms. B got terribly ill. Why? She said, “I drink that kind of wine all the time.”
LIVER FAILURE Hematologic disorders as the liver fails the spleen takes over some of the function of the liver Anemia- due to splenomegaly Thrombocytopenia- due to splenomegaly coagulation defects- leukopenia due to splenomegaly As your spleen grows larger, it begins to filter normal red blood cells as well as abnormal ones, reducing the number of healthy cells in your bloodstream. It also traps too many platelets. Eventually, excess blood cells and platelets can clog your spleen, interfering with its normal functioning.
LIVER FAILURE Endocrine disorders Fluid retention, hypokalemia, Lack of metabolism of aldosterone, too much remains in the system disordered sexual functions Which hormones would cause these endocrine disorders? Failure of Cholesterol/Steroid formation
LIVER FAILURE (CONT.) Skin disorders Jaundice, red palms, spider nevi Hepatorenal syndrome- Deteriorating liver function is believed to cause changes in the circulation altering blood flow in the kidneys. The renal failure of HRS is a consequence of these changes in blood flow Azotemia, increased plasma creatinine, oliguria- decreased production of urine Hepatic encephalopathy- caused by accumulation in the bloodstream of toxic substances that are normally removed by the liver Asterixis, confusion, coma, convulsions Asterixis : An uncontrollable flapping of the hands that becomes noticeable when patients stretch out their arms, palms out, as if stopping traffic.
JAUNDICE IN A PERSON WITH HEPATITIS A
QUESTION What causes jaundice? a. Increased bilirubin levels b. Anemia c. Thrombocytopenia d. Leukopenia
ANSWER a. Increased bilirubin levels Rationale: Erythrocytes are normally broken down in the spleen at the end of their life span. The end product of RBC metabolism is bilirubin. Bilirubin is sent to the liver to be metabolized; if the liver is not functioning properly, the bilirubin accumulates and causes jaundice (an abnormal yellowing of the skin and mucous membranes).
HEPATITIS Viral hepatitis Hepatitis A virus (HAV) Hepatitis B virus (HBV) Hepatitis B–associated delta virus (HDV) Hepatitis C virus (HCV) Hepatitis E virus (HEV)
DISCUSSION Which hepatitis viruses are most likely to be the problem in: An asymptomatic drug abuser? A nursing student who has spent the last two months volunteering in an orphanage in Mali? An infant whose mother has hepatitis? C E B
CHRONIC VIRAL HEPATITIS Caused by HBV, HCV, and HDV Principal worldwide cause of chronic liver disease, cirrhosis, and hepatocellular cancer Chief reason for liver transplantation in adults
ALCOHOLIC LIVER DISEASE Fatty liver (steatosis) Liver cells contain fat deposits; liver is enlarged Alcoholic hepatitis Liver inflammation and liver cell failure Cirrhosis Scar tissue partially blocks sinusoids and bile canaliculi
QUESTION Which of the following is the least virulent strain of hepatitis? a. HAV b. HBV c. HCV d. HDV
ANSWER a. HAV Rationale: HBV, HCV, and HDV are all virulent strains that may lead to chronic viral hepatitis. HAV is most commonly transmitted by the fecal-oral route (e.g., contaminated food or poor hygiene) and does not typically have a chronic stage (it does not cause permanent liver damage).
VEINS DRAINING INTO THE HEPATIC PORTAL SYSTEM Portal hypertension causes pressure in these veins to increase Varicosities and shunts develop Organs engorge with blood
EFFECTS OF PORTAL HYPERTENSION Ascites & Caput medusae Hemorrhoids
CHOLESTASIS AND INTRAHEPATIC BILIARY DISORDERS Bile flow in the liver slows down Bile accumulates and forms plugs in the ducts Ducts rupture and damage liver cells Alkaline phosphatase released into blood Liver is unable to continue processing bilirubin Increased bile acids in blood and skin Pruritus (itching)
THE FATE OF BILIRUBIN Hemoglobin from old red blood cells becomes bilirubin The liver converts bilirubin into bile Why would a man with liver failure develop jaundice? unconjugated bilirubin in blood bilirubinemia jaundice liver links it to gluconuride conjugated bilirubin bile
BILIARY TRACT Hepatic duct Pancreatic duct Gallbladder Cystic duct Common bile duct Ampulla of Vater Sphincter of Oddi
DISORDERS OF THE GALLBLADDER Cholelithiasis (gallstones) Cholesterol, calcium salts, or mixed Acute and chronic cholecystitis Inflammation caused by irritation due to concentrated bile Choledocholithiasis Stones in the common bile duct Cholangitis Inflammation of the common bile duct
BILE IN THE INTESTINES Emulsifies fats so they can be digested Passes on to the large intestine Bacteria convert it to urobilinogen º Some is lost in feces º Most is reabsorbed into the blood Returned to the liver to be reused Filtered out by the kidneys urine
THE PANCREAS Pancreas Exocrine pancreas releases digestive juices through a duct to the duodenum Endocrine pancreas releases hormones into the blood
EXOCRINE PANCREAS Acini produce: Inactive digestive enzymes Trypsin inactivator Bicarbonate (antacid) These are sent to the duodenum when it releases secretin and cholecystokinin In the duodenum, the digestive enzymes are activated
QUESTION Tell whether the following statement is true or false. The exocrine pancreas produces insulin.
ANSWER False Rationale: Beta cells of the endocrine pancreas produce insulin; the exocrine pancreas produces digestive enzymes that are secreted into the small intestine through the common bile duct.
BILIARY REFLUX 5. Bile in pancreas disrupts tissues; digestive enzymes activated 4. Bile goes up pancreatic duct 1. Gallbladder contracts 2. Bile is sent down common bile duct 3. Blockage forms in ampulla of Vater: bile cannot enter duodenum
AUTODIGESTION OF THE PANCREAS Activated enzymes begin to digest the pancreas cells Severe pain results Inflammation produces large volumes of serous exudate hypovolemia Enzymes (amylase, lipase) appear in the blood Areas of dead cells undergo fat necrosis Calcium from the blood deposits in them º Hypocalcemia
CHRONIC PANCREATITIS AND PANCREATIC CANCER Have signs and symptoms similar to acute pancreatitis Often have: Digestive problems because of inability to deliver enzymes to the duodenum Glucose control problems because of damage to islets of Langerhans Signs of biliary obstruction because of underlying bile tract disorders or duct compression by tumors