Liver Flashcards
(154 cards)
Where is live Located?
Located in RUQ of abdomen
2 lobes made up of thousands of lobules
Lobules function:
centered on a branch of the hepatic vein (“central vein”)
interconnected by small ducts
contain hepatocytes, separated by sinusoids
“portal triads”at the corners of adjacent lobule–>branches of the bile duct , portal vein, hepatic artery
What is the heaptic duct?
Transports bile produced by liver cells to the gallbladder and duodenum
Unique function of liver cells
Liver cells can regenerate
About 70% of the liver tissue can be destroyed before the body is unable to eliminate drugs and toxins via the liver
Blood flow to liver
~25% of the cardiac output (~1500 mL of blood flow/minute)
Has a dual blood supply
Describe the blood supply flow to the liver
venous flow in from the portal vein*
venous blood from the small intestine (absorbed nutrients, drugs, toxins) directly to the liver
pancreatic venous drainage (pancreatic hormones)
spleen (bacteria, byproducts of blood-cell recycling)
arterial flow in from the hepatic artery
liver oxygenation
venous flow out through the hepatic vein
Blood from both portal vein and hepatic artery mixes together in sinusoids and exits the liver through the hepatic vein
Connected to the GI tract via portal veins and bile ducts
Major functions of the liver
Excretion
Bile* - produced by hepatocytes; metabolizes cholesterol and fat and detoxifies drugs and toxins
Metabolism
Bilirubin, drugs, nutrients, hormones
CHO, lipids, amino acids, hormones/steroids
Storage
Vitamins/minerals (B12, iron), CHO
Synthesis
Plasma proteins (albumin, coagulation proteins, other transport proteins)
Responsibility of gallbladder
Stores and concentrates bile (typically concentrated 5 fold in the gallbladder by absorption of water and electrolytes)
Bile Functions
Bile functions:
Emulsification: dietary fat, chol, vitamins
Elimination of waste: excess chol, xenobiotics, bilirubin
contraction of Gallbladder and bile duct is by…..
Stimulus (food in duodenum) Cholecytikinin
What is enetrohepatic recirculation?
enterohepatic recirculation (95% of bile acids reabsorbed) – some lost in feces, body makes up for it
What is Bilirubin? What is its metabolism?
End product of heme degradation
From breakdown of RBC in spleen/liver
Free bilirubin –> Insoluble-bound to albumin for transport to liver (measured as “indirect bilirubin”)
Bilirubin Metabolism:
Glucuronidated in liver (“direct bilirubin”)
Excreted in bile
Describe billirubin process
Liver Dx can be….
Can be acute or chronic, focal or diffuse, mild or severe, and reversible or irreversible…
Describe liver damage and the types? Is it reversible?
Acute damage to the functional cells of the liver without destruction of the liver’s capacity for regeneration is generally reversible (may be irreversible)
Fulminant liver failure/end-stage disease
insufficient residual hepatocytes to maintain minimal essential liver functionsirreversible
Descirbe the pattern of hepatocellular injury?
Etyiology of Hepatic Injury
Viruses (HAV, HBV, HCV, HDV, other Epstein bar virus as example )
Drugs (Rx, OTC, herbals)
Environmental toxins (chlorinated pesticides, insecticides, etc.)
Alcohol
What are the two types of hepatic injury?
CHOLESTASIS
HEPATOCELLULAR
Define cholestasis.Leads to?
A failure of normal amounts of bile to reach the duodenum’
Leads to accumulation of bile in liver cells and biliary passages (intra vs extrahepatic)
Causes of cholestasis
Cholelithiasis (gall stones) - most common
Tumor, viral hepatitis, alcohol-related liver disease, drugs
Primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC)
What is primary biliary cholangitis. Stat?
Caused by the slow, immune-mediated destruction of small bile ducts within the liver (impaired excretion of bile)
Leading cause of liver transplant in women in Canada
What is primary sclerosing cholangitis?What is it associated with?
Involves progressive inflammation and fibrosis affecting any part of the biliary tree
Leads to the progressive destruction of bile ducts
Commonly associated with inflammatory bowel disease
What is choletstaic syndrome? Sx?
Blockage of bile flow
Pruritis
Jaundice
Dark Urine
Light coloured stools (greenish)
Steatorrhea (fatty stools)
Xanthoma (growths under skin due to bile salts) and xanthelasma (little growths around the eyelids)
Hepatomegaly
Treatment of choleithiasis?
Ursodeoxycholic acid (ursodiol