Liver Flashcards
What are the 5 functions of the liver?
- Detoxification and drug metabolism
- Lipid and carb metabolism
- Protein synthesis
- Synthesis and excretion of bile acids
- Conjugation and excretion of bilirubin
Describe detoxification and drug metabolism
-Clears blood of toxins and metabolic wastes (bilirubin and ammonia) and hormones (estrogen/sex hormones)
What are the 2 places that waste goes?
- In bile (bilirubin)
- Converts toxic chemical to nontoxic chemical (ammonia to urea)
Describe lipid and carbohydrate metabolism
-Converts glucose into glycogen for energy storage and reconverts it to glucose if needed
The liver synthesizes ______ and ______
-Triglycerides and cholesterol
The liver also burns fat. This is the byproduct
Ketones/ketoacids
What are examples of proteins that are made by the liver
- Albumin
- Clotting factors
- Transport proteins
T/F- The liver excretes bilirubin into bile
True
What is added to secrete bilirubin into bile?
Glucuronide
What do intestinal bacteria convert bilirubin into?
Bilirubin –> Urobilinogen (this makes poop look brown)
What is the main constituent of bile
Bile acids
What is used to make bile acids
Cholesterol
What do bile acids do?
-Allow ingested fats to become water soluble and allow pancreatic lipase to act
How are bile acids reabsorbed?
Enterohepatic circulation
_______ refers to excretion of bile acids (made from cholesterol) from the liver into the intestine and the reabsorption of most of the bile acids (and their cholesterol) by the intestine for recirculation through the portal system and reuse by the liver.
Enterohepatic circulation
Where does most absorbed cholesterol come from?
Cholesterol absorbed by the intestine from reabsorbed bile acids- not dietary cholesterol
Liver complications include toxic accumulations such as…
- Toxic accumulations (ammonia, bilirubin, drugs, hormones)
- Bleeding (lack of coagulation factors)
- Edema (deficiency in plasma albumin)
Generalized edema=
anasarca
abdominal edema=
ascites
A deficiency in bile acids causes…
- Failure to absorb intestinal fat
- Failure to absorb fat-soluble vitamins
What causes jaundice?
- Increase levels of bilirubin in the blood
- May be conjugated or unconjugated
What are the main causes of hepatitis?
- Viral infection
- Autoimmune
What are 2 types of degeneration?
Hydropic or fatty
Is degeneration reversible?
-YES!
What causes hydropic deneration?
-Too much water
What causes fatty degeneration?
Fat (seen in alcohol excess)
Hepatitis and chronic alcohol abuse can kill cells _____ at a time
One at a time- infarcts are rare
This is when the flow of bile stops or slows
Cholestasis
What does cholestasis lead to?
-Accumulation of bile acids and cholesterol in the blood
This is loss of hepatic metabolic function
Hepatic failure
Describe unconjugated bilirubin
- Not water soluble
- tightly bound to albumin for transport to the liver
In the liver, bilirubin is joined (conjugated) with _______
glucuronine
What does the joining of glucuronine do?
-Makes water soluble conjugated bilirubin
This is a superimposed acute renal failure
Hepatorenal syndrome
Describe hepatorenal syndrome
-Related to decreased renal blood flow
-Decreased filtering and kidney excretion
(the kidney cells are structurally normal and can return to normal function with a liver transplant)
_______ occurs with increasing levels of ammonia in the blood
Hepatic encephalopathy
What are the 4 stages of hepatic encephalopathy
- Irritability and personality changes
- Lethargy and disorientation
- Deep sleep
- Coma
What is a DISTINCT clinical sign of hepatic encephalopathy
- Asterixis
- Flapping tremor in the upper extremities (hepatic flap)
What are the 3 types of jaundice?
- Prehepatic
- Hepatic
- Post hepatic
Describe prehepatic jaundice
-Increased levels of UNCONJUGATED bilirubin in the blood
What causes preheptic jaundice
-Hemolytic anemia
-Sickle cell disease
(bc it increases production of unconjugated bilirubin)
This is caused by interference with the livers ABILITY TO CONJUGATE bilirubin or to SECRETE it after conjugation
Hepatic Jaundice
Are increased levels of blood bilirubin due to conjugated or unconjugated bilirubin in hepatic jaundice?
Either one
This is caused by the obstruction of bile flow inside or outside the liver
Posthepatic jaundice
IN posthepatic jaundice, are increased levels of blood bilirubin conjugated or unconjugated?
Conjugated
What is the most common cause of unconjugated bilirubinemia?
Gilbert syndrome
This is a modest elevation in serum bilirubin because of a genetic deficiency of uridine diphsophate glucuronyl transferase
Gilbert Syndrome
What is uridine diphosphate glucuronyl transferase
An enxyme in the metabolic pathway
- about 7% of the population is affected
- Men more than women
These 3 enzymes spill from damaged hepatocytes
- LDH
- AST
- ALT
DIRECT Bilirubin levels measure the _________ bilirubin
Conjugated bilirubin
INDIRECT Bilirubin levels measure the _________ bilirubin
Indirect= total- direct and it represents UNCONJUGATED plus all bound bilirubin
What are the TRUE liver function tests
-Albumin
-PT
-PTT
(because clotting factors are liver proteins)
