Liver and Biliary Flashcards
How is the liver connected to the intestine and the great vessels?
The liver is connected to the gallbladder on the inferior side. Also at the hilus is the dual blood supply
- hepatic artery: arterial oxygenated
- portal vein: venous rich nutrient
Which cells form liver lobules?
hepatocytes are arranged into lobules
What are the main functions of the liver?
- *Excretory:** bile
- *Metabolic:** processing factory for food
- *Storage:** carbs/lipids
- *Synthetic:** major plasma proteins (except immunoglobulins)
What are the consequences of portal hypertension?
- formation of varicosities d/t increased pressure
- chronic passive congestion in the spleen (portal vein connects)
- transudation of fluid >> ascites
How is bilirubin formed and excreted?
Senescent RBCs are taken up by phagocytic cells of the spleen and kupffer cells of the liver. Within these cells, hgb is degraded to heme and globin.
Heme loses the iron and is transformed into yellow pigment = bilirubin. Bilirubin is then bound in the blood by albumin = unconjugated. Unconjugated which is not water soluble is taken up by liver cells and conjugated to glucuronide. Bilirubin bound to glucuronide = water soluble. Bacteria not used in the intestine is converted by bacteria to urobilinogen.
Which enzymes are released into the circulation from damaged liver cells?
AST and ALT are ubiquitous enzymes that are elevated in blood after liver injury (and also other organs).
Alkaline phosphatase is used as marker for bile duct obstruction.
What are three principal forms of jaundice and what causes each of them?
- *Prehepatic:** unconjugated, usually due to excessive bilirubin formation secondary to hemolysis
- malaria, Gilbert’s disease*
Hepatic: mixed conjugated, unconjugated, can be caused by acute or chronic hepatitis, hepatotoxicity, cirrhosis, drug-induced hepatitis and alcoholic liver disease. Cell necrosis reduces the liver’s ability to metabolize and excrete bilirubin** **
**Posthepatic: **conjugated, disturbance in excretion, usually (gallstones) at the level of the common bile duct.
Compare the biochemical laboratory findings in prehepatic, hepatic, and posthepatic jaundice.
unconjugated >> does NOT cross BBB, does not filter in urine
conjugated >> excreted in urine
What are the causes of viral hepatitis?
Hepatitis A, B, C, D, E
Hepatotropic viruses: mono, epstein-barr, herpes, CMV
Compare viral hepatitis A with viral hepatitis B and C.
Hepatitis A and C and RNA viruses; Hepatitis B is aDNA virus.
Hep A is F/O, while B and C are Par/Sex.
Hep A is NOT associated with a carrier state. Hep B and C are.
A vaccine is available for A and B. NOT for C.
Explain the signficance of serologic tests for the diagnosis of hepatitis.
HBsAg: surface antigen
released early, can be detected 1 week after onset
Persists only in patient who develop CHRONIC
HBcAg: core antigen
Antibodies appear in all infected persons
IGM first, IgG later
HBeAg: e antigen
Appears early, but disappears during ICTERIC stage
*presence in CHRONIC is a marker of INFECTIVITY
Compare the findings in acute and chronic hepatitis.
In hepatitis B there is a preicteric, icteric, and convalescent phase:
Preicteric: weakness, N/V, mild enlargement/tenderness of liver, rash, dark urine
* the more profound jaundice = more likely recovery
mild jaundice = likely transition to chronic
Chronic = intralobular inflammation, portal tract inflammation, disruption of lobular architecture secondary to aggresive inflammation and fibrosis
What is cirrhosis, and how does this disease present clinically?
= chronic liver disease characterized by loss of normal liver structure and function
irreversible and incurable
- coma
- thin hair
- facial telangiectasia
- jaundice
- parotid bland enlargement
- spider nevi
- muscle wasting, gynecomastia
- HSM
- caput medusa
- ascites
- palmar erythema
- absent of reduced pubic hair, small testes
- edema, purpura
What are the common causes of cirrhosis?
Alcohol abuse
Hepatitis B and C
Hereditary metabolic diseases
- Hemochromatosis
- Wilson’s disease
- Alpha antitrypsin
Autoimmune disease
- biliary cirrhosis
- primary sclerosing cholangitis
- autoimmune hepatitis
drug use
biliary obstruction
- cystic fibrosis
- gallstones
or cryptogeneic
Compare portal and biliary cirrhosis.
portal >> results from liver cell necrosis followed by ingrowth of fibrous tissue from the portal tracts
fibrous scars increase, incirciling remaining liver parenchyma and inhibiting ability to regenerate.
biliary >> results from diseases of the biliary tree, primary or secondary
primary = autoimmune disease
secondary = develops after prolonged, partial or complete obstruction of bile flow