Hepatobiliary Flashcards
What is the only plasma protein that is not formed by the liver?
gamma globulin
How is heme coverted into bilirubin?
Heme → biliverdin (in the mononuclear cells by heme oxygenase) → unconjugated bilirubin (lipophilic; by biliverdin reductase) → conjugated bilirubin (water soluble; via glucuronidation)
Iron metabolism in liver
Absorbed in GI –> ferroportin (regulated by hepcidin) –> transferrin –> hepatocite with apoferritin and hemosiderin
What are the two hormones that can activate phosphorylase and facilitate glycogenolysis?
Epinephrine
Glucagon
How many ATPs are produced during glycolysis, Krebs cycle and oxidative phosphorylation?
Glycolysis: 2
Krebs cycle: 2
Oxidative phosphorylation: 34
True or False: ATP provides negative feedback to inhibit the glycolysis.
True
ATP inhibit phosphofructokinase, which is the rate limiting enzyme
It covert
What does phosphofructokinase do?
It converts fructose-6-phosphate to fructose-1,6-bisphosphate.
True or False: Citrate ions from citric acid cycle provides negative feedback to inhibit the glycolysis.
True
Inhibit phosphofructokinase
Besides glycolysis, what is the pathway that is responsible for up to 30% of glucose breakdown in the liver and adipose tissue?
Pentose phosphate pathway
What are the three main types of lipids in the body?
Triglyceride (contains fatty acid)
Phospholipids (contains fatty acid)
Cholesterol (do not contain fatty acid)
How does body utilize fatty acid as source of energy?
fatty acids are converted to acetyl-CoA via 𝜷-oxidation → acetyl-CoA enters Krebs cycle → 22 ATP
List 3 hormones that facilitate lipolysis.
Thyroid hormone
Epinephrine
Cortisol
What is the normal ratio of body tissue protein and plasma protein?
33:1
For the liver bloody & oxygen supply, how many percentage are from the portal vein and how many percentage are from the hepatic artery?
Blood: 80% from portal vein, 20% from hepatic artery
Oxygen: 50% from portal vein, 50% from hepatic artery
What are the amino acid participating in the urea cycle?
Aspartate
Ornithine
Arginine
* Citrulline
What are the two hormones that facilitate protein synthesis? Which hormone facilitates protein breakdown?
Protein synthesis: insulin, growth hormone
Protein breakdown: glucocorticoid
What is the function of space of Disse?
allow excessive fluid from the liver sinusoid enter and drained from the lymphatic system
How many liver lobes are in dogs?
Four lobes with four sublobes and 2 processes
Right lateral, Right medial, Left lateral, Left medial, caudate, quadrate
What is the main difference in the bile duct anatomy in dogs and cats?
Dogs:
- Common bile duct enters the duodenum at the major duodenal papilla adjacent to the pancreatic duct (not conjoined)
- The accessory pancreatic duct (which is the main pancreatic enzymes secretion site) enters the duodenum a the minor duodenal papilla
Cats:
- The common bile duct and the pancreatic duct conjoin before enter the duodenum at the major duodenal papilla
- Only approximately 20% of cats have a smaller, accessory pancreatic duct that exits at a minor duodenal papilla
List 5 substances that is in the bile.
1) Bile acid
2) Cholesterol
3) Bilirubin
4) Phospholipids
5) Water
6) Bicarbonate
How many percentage of the liver removal can dogs tolerate?
70%
* The main issue is the liver being unable to accommodate the portal vein blood flow and develop portal hypertension
How soon does liver regeneration start and when is the peak?
starts within hours
Peak at 3 days
Which liver lobe is most likely to develop liver lobe torsion?
Left lateral
What are the two common concurrent endocrine disease with gallbladder mucocele?
Hyperadrenocorticism
Hypothyroidism
Explain the enterohepatic circulation of bile acid.
Cholesterol enters the liver → breaks down to unconjugated primary bile acid → conjugates with glycine, taurine → conjugated bile acid and enters the gall bladder → enters the intestines at the level of duodenum → being actively absorbed at ileum (90%) / the rest 10% modified by bacteria (secondary bile acids) and enters the colon → the reabsorbed (95%) conjugated and unconjugated bile acids are efficiently extracted by hepatocyte transporters → only 5% remains in the systemic circulation for us to measure.
What is the reason of doing pre- and post-prandial bile acid test?
Providing food is a challenge to see if the liver can handle extra bile acid after the bile acid is secreted into the GI tract.
How do you interpret the bile acid test.
Bile acid concentrations >25-30 μmol/L in dogs and > 25 μmol/L in cats are suggestive of hepatobiliary disease.
- whether pre- or post- is higher doesn’t really matter
Eclinpath
What are the three differential for abnormally high bile acid test?
Hepatic dysfunction
Hepatic vascular anomaly
Bile duct obstruction
What are the surgical options for PSS?
- Suture ligation
- Gradual attenuation with ameroid constrictors
- Gradual attenuation with cellophan bands
What is normal portal vein pressure?
6-10 mmHg
What are the clinical signs to observe after PSS surgery for portal hypertension?
Seizure
Pain
Intra-abdominal hypertension
Hypovolemic shock
Vomiting, diarrhea
Distended abdomen with effusion
What are the two common causes for hepatic encephalopathy in dogs and cats, respectively?
Dog: CPSS, formation of acquired portosystemic collateral vessels (APSC) due to portal hypertension
Cat: CPSS, arginine deficiency due to hepatic lipidosis
What is the classification of HE?
Type A: due to acute hepatic failure
Type B: due to portal systemic bypass (e.g. CPSS) with normal hepatic function
Type C: due to cirrhosis, PH or acquired portal systemic shunting
- Episodic, persistent, minimal
What is the important enzyme to covert glutamine to ammonia and glutamate?
glutaminase (high level in enterocytes)
What are the two metabolic pathways for ammonia in the liver? what cells are responsible for that? what are their affinity and capacity?
1) Urea cycle, periportal hepatocytes, low affinity but high capacity
2) Glutamine synthesis, perivenous hepatocytes, high affinity but low capacity
What composes the portal triad?
Portal vein
Hepatic artery
Bile duct
which hepatic zone does acetaminophen most likely to cause injury?
zone 3
Which hepatic zone does gluconeogenesis happen? What about glycolysis?
Gluconeogenesis: zone 1
Glycolysis: zone 3 (anaerobic metabolism)