chapter 38: disorders of hepatobiliary and exocrine pancreas function

liver

giant filter (3lbs)

largest visceral organ

produces bile (to digest fat)

gall bladder

stores and concentrates bile

pancreas

secretes digestive enzymes (exocrine)

regulates blood glucose (endocrine)

exocrine glands

secrete substances into an organ

endocrine glands

release hormones into the blood

hepatic artery

300 mL/min

hepatic portal vein

1050 mL/min

carries toxic material to liver to be metabolized before draining into inferior vena cava

blood from portal veins...

supplies 60-70% of the liver's oxygen needs

liver stores about 450 mL of blood

liver sinusoids

functional unit of the liver

sinusoids empty into central veins

sinusoid

irregular shaped blood vessel

bile canaliculi (little canals)

at the back end of each hepatic cell

bile is released into bile canaliculi

bile is carried to bile duct, then to gallbladder to be stored

physiologic functions of liver

carbohydrate metabolism, fat metabolism, protein metabolism

carbohydrate metabolism

stores glycogen and synthesizes glucose

fat metabolism

forms lipoproteins, converts carbs and proteins to fat, produces, recycles, and eliminates cholesterol, makes ketones from fatty acid

protein metabolism

breaks down proteins, makes plasma proteins and clotting factors, forms urea

bile formation

bile; conjugated bilirubin, cholesterol, bile salts, fat

bile salts emulsify dietary fats

most bile salts get reabsorbed into portal circulation and get recycled around 18 times before being eliminated

by-product of hemoglobin breakdown is...

bilirubin

fate of bilirubin

hemoglobin from old red blood cells becomes unconjugated bilirubin (not water-soluble)

liver transforms unconjugated bilirubin to conjugated bilirubin (water-soluble)

too much unconjugated bilirubin leads to jaundice

cholestasis

bile flow in liver slows down or stops

bile accumulates and forms plugs in the ducts

hepatitis

inflammation of the liver

hepatitis a virus

least horrible, in the united states

wash hands

hepatitis e virus

globally, contaminated water

hepatitis c virus

no vaccine

hepatitis d virus

rare, must have b

chronic viral hepatitis

principal cause of chronic liver disease, cirrhosis, and hepatocellular cancer

transmitted through blood-to-blood transfer

main reason for liver transplantation in adults

most often caused by hbv, hcv, and hdv

fatty liver (steatosis)

common cause is alcohol

impairment of the normal process of eliminating triglycerides

liver cells contain fat deposits, liver is enlarged

NO MORE ALCOHOL

alcoholic hepatitis

on the way to liver failure

liver inflammation and liver cell failure

occurs along with fatty liver

cirrhosis

scar tissue partially blocks sinusoids and bile canaliculi (blood and bile trapped in liver)

asymptomatic until late

avoid alcohol, liver transplant

portal hypertension

increased pressure in the portal venous system

cirrhosis is the most common cause

big spleen (blood shunted to splenic vein)

portal hypertension tx

beta blockers to decrease blood pressure

banding to block blood vessels (cut off blood flow)

sclerotherapy (hypertonic saline solution injected into bleeding varices)

liver failure

hepatitis a, b, c, cirrhosis, malnutrition, acetaminophen overdose

tx (reverse damage if overdose, liver resection or transplant)

liver cancer

most common is hepatocellular

from chronic hepatitis b and c and alcoholic cirrhosis

biliary tract

passageway for the delivery of bile from the liver to the intestines

cholelithiasis (gallstones)

cause pain when lodged in the bile duct, cause inflammation

hardened deposits of bile or too much cholesterol secretion

acute and chronic cholecystitis

inflammation of the gallbladder

accumulation of bile, irritation and inflammation

gallstones obstructing the exit, tumors, high fat diet

exocrine pancreas

releases digestive enzymes through a duct to the duodenum

exocrine/acinar cells produce...

inactive digestive enzymes

sent through pancreatic duct to the duodenum where digestive enzymes are activated

pancreatitis

auto digestion of the pancreas

activated enzymes digest the cells of the pancreas

gallstones blocking pancreatic duct, alcohol abuse

acute pancreatitis

single "attack"

pancreas returns to normal

chronic pancreatitis

life-threatening

pancreatitis tx

pancreatic enzymes, surgery

pancreatic cancer

cause is unknown

radiation and chemo, tumor excision or pancreatectomy

pancreatic enzyme replacement therapy, insulin