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__________ represents the end stage of chronic liver disease in which much of the functional liver tissue has been replaced by fibrous tissue.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

SYSTEM

SYSTEM INTERACTION

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

TrueRationale: 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. Carbohydrateb. Proteinc. Fatd. All of the above

ANSWER

c. FatRationale: 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 levelsb. Anemiac. Thrombocytopeniad. Leukopenia

ANSWER

a. Increased bilirubin levelsRationale: 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

ALCOHOLIC LIVER

ALCOHOLIC LIVER

LIVER CANCER

QUESTION

Which of the following is the least virulent strain of hepatitis?

a. HAVb. HBVc. HCVd. HDV

ANSWER

a. HAVRationale: 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

PORTAL HYPERTENSION

PORTAL HYPERTENSION

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 fecesº 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

FalseRationale: 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 themº 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