Liver Flashcards
Explain hepatic portal circulation
A ___ is located b/w two ___ beds. The hepatic portal vein collects __ from ___ in visceral structures located in the ___ and empties into the ___. Hepatic veins __ blood to the __ __ __.
A vein is located b/w two capillary beds. The hepatic portal vein collects blood from capillaries in visceral structures located in the abdomen and empties into the liver. Hepatic veins return blood to the inferior vena cava.
What makes up the portal triad?
hepatic portal vein (80%)
hepatic artery (20%)
bile duct
lymphatic vessel
Describe the role of hepatocyte function (bile)
Liver - hepatocytes synthesize cholesterol to form primary bile acids –> Bile acid pool –> AA (glycine and taurine) conjugate to form bile salts in bile –> Gallbladder: some bile is stored for release during eating and Duodenum and jejunum (bile salts emulsify fats and form micelles to transport fats through the unstirred layer, Micelles release fats at the brush border, Free bile salts proceed through the intestinal lumen –>Rectum: 15%-35% of bile salts are excreted in feces, Ileum and Colon: bile salts are actively transported across the intestinal lumen or are de- conjugated by bacteria into secondary bile acids that diffuse passively across the lumen –> Hepatic portal vein: 65-85% of bile salts and secondary bile acids enter the circulation with protein binding and are transported to the liver
Name 5 hepatic injuries and findings
fibrosis and cirrhosis lab evaluation of liver disease jaundice cholestasis portal hypertension
Fibrous tissues in formed in response to
inflammation
What is bridging fibrosis
with time, fibrous stands link regions of the liver
With continuing fibrosis and parenchymal injury, the liver is subdivided into
nodules of regenerating hepatocytes surrounded by scar tissue
Fibrosis is considered a _____ consequence of _______ damage and has lasting consequences on patterns of _____ _____ and ______ ___ _______
irreversible
hepatic
blood flow and perfusion of hepatocytes
Lab eval of liver disease: hepatocyte integrity
serum aspartate aminotransferase (AST, SGOT)
serum alanine aminotransferase (ALT, SGPT)
Lab eval of biliary tract integrity
serum alkaline phosphatase (AP, ALP, ALKP, etc)
serum y-glutamyltransferase (GGT)
Lab eval of bilirubin
direct (conjugated)
indirect (unconjugated)
Lab eval of hepatocyte function
serum albumin
prothrombin time
serum ammonia
Consequences of liver disease
4H, JF, GP, SWM
hyPO -albuminemia, ammonemia, glycemia, gonadism
Jaundice and cholestasis
gynecomastia and palmar erythemia
spider angiomas, weight loss, muscle wasting
Consequences of liver disease: Hepatic portal HTN
SEA HC
Splenomegaly Esophageal varices Ascites Hemorrhoids Caput medusae
Consequences of liver disease: Life Threatening Complications (HHH MEC)
Hepatic encephalopathy Hepatorenal syndrome Hepatocellular carcinoma Multiple organ failure Esophageal varices rupture Coagulopathy
Explain bilirubin metabolism and elimination
- Normal bilirubin production (.2-.3g/day) is derived primarily from the breakdown of senescent circulating erythrocytes, with a minor contribution from degradation of tissue heme containing proteins
- Extrahepatic bilirubin is bound to serum albumin and delivered to the liver
- Hepatocellular uptake
- Glucuronidation by glucuronosyltransferase in the hepatocytes generates bilirubin monoglucuronides and diglucuronides which are water soluble and readily excreted into bile.
- Gut bacteria deconjugate the bilirubin and degrade it to colorless urobilinogens. The urobilinogens and the residue of intact pigments are excreted in the feces with some reabsorption and re-excretion into bile
Jaundice: accumulation of excess ___ in ____
bilirubin in blood
Jaundice: Causes
excess bilirubin production reduced hepatic uptake impaired conjugation decreased heptocellular excretion impaired bile flow
Jaudice:
excess bilirubin production, reduced hepatic uptake,
impaired conjugation result in ___ ___ ___
increased unconjugated bilirubin
Jaudice:
excess bilirubin production, reduced hepatic uptake,
impaired conjugation result in increased unconjugated bilirubin:
____ to water, tight bound to ___, NOT excreted by ___
insoluble in water, tightly bound to albumin, not excreted by kidney
Jaudice:
excess bilirubin production, reduced hepatic uptake,
impaired conjugation result in increased unconjugated bilirubin:
Unbound plasma fraction
diffused in tissue
produces toxic injury
increases in hemolytic disease of the newborn
may lead to severe neurological damage
Jaundice: decreased heptocellular excretion, impaired bile flow result in ___ ____ ____
increased conjugated bilirubin
Jaundice: decreased heptocellular excretion, impaired bile flow result in increased conjugated bilirubin: ___ in water, ___ bound to albumin, excreted by ____
soluble in water, weakly bound to albumin, excreted by kidney
Cholestasis: in the parenchyma, cholestatic heptocytes are ___ with dilated canalicular spaces, ___ cells may be seen, and ___ cells frequently contain regurgitated ___ ___.
enlarged with dilated canclicular spaces, apoptic cells may be seen and Kupffer cells frequently contain regurgitated bile pigment
Cholestasis: in the portal tract of obstructed livers, there is also bile ___ ____, ___, bile pigment ___, and eventually ____ ____
bile ductular proliferation, edema, bile pigment retention, eventually neutrophilic inflammation
____ immediately adjacent to portal trans are ___ and undergoing __ ___
hepatocytes
swollen
toxic degeneration
Hepatic failure is __ and __ hepatic destruction
sudden and massive
Hepatic failure is the often end point of
progressive liver damage
Hepatic failure means that ___% of liver function must be lost
80-90%
Hepatic failure is __ ___
life threatening (multiple organ failure)
What are the special problems in hepatic failure?
hepatic encepalopathy
hepatorenal syndrome
