Liver Function and Blood Supply Quiz
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Questions and Answers

What are the three systems the liver is composed of?

Hepatocyte, Biliary system, Reticuloendothelial system

What does the hepatic artery supply to the liver?

  • Insulin
  • Oxygen and nutrients (correct)
  • Bile
  • Waste products

    • What does the portal vein connect?

  • The liver and the spleen
  • Capillary beds between the GIT and the liver (correct)
  • The stomach and the small intestine
  • The heart and the liver

    • The hepatic vein carries deoxygenated blood from the liver to the IVC.

    <p>True</p> Signup and view all the answers

    What are the main functions of the hepatocyte?

    <p>All of the above</p> Signup and view all the answers

    What is the primary function of the biliary system?

    <p>Production of bile salts and their transport for digestion</p> Signup and view all the answers

    Which of the following is NOT a function of the reticuloendothelial system?

    <p>Production of bile salts</p> Signup and view all the answers

    Which of the following is a non-hepatic cause of abnormal liver function tests?

    <p>Hemolysis</p> Signup and view all the answers

    What does the term 'sensitivity' refer to in terms of a liver function test?

    <p>The ability of the test to correctly identify individuals who have a liver disease</p> Signup and view all the answers

    What is the primary precursor for the production of bilirubin?

    <p>Hemoglobin</p> Signup and view all the answers

    Where does the breakdown of hemoglobin primarily occur?

    <p>Spleen</p> Signup and view all the answers

    What is the primary form of bilirubin transported in the blood to the liver?

    <p>Unconjugated bilirubin</p> Signup and view all the answers

    The process of conjugating bilirubin in the liver involves attaching glucuronic acid to unconjugated bilirubin.

    <p>True</p> Signup and view all the answers

    What is the primary mechanism of bilirubin excretion from the body?

    <p>Through the intestines in bile</p> Signup and view all the answers

    Which form of hyperbilirubinemia is characterized by an elevated level of unconjugated bilirubin?

    <p>Prehepatic hyperbilirubinemia</p> Signup and view all the answers

    Which of the following conditions can cause prehepatic hyperbilirubinemia?

    <p>Hemolytic anemia</p> Signup and view all the answers

    Neonatal physiological jaundice is a type of conjugated hyperbilirubinemia.

    <p>False</p> Signup and view all the answers

    What is the primary cause of hemolytic disease of the newborn?

    <p>Rh incompatibility between mother and fetus</p> Signup and view all the answers

    What is the purpose of administering anti-D immunoglobulin to Rh-negative mothers?

    <p>To prevent the development of hemolytic disease of the newborn</p> Signup and view all the answers

    Which of the following is NOT a contributing factor to breast milk hyperbilirubinemia?

    <p>Increased bilirubin excretion</p> Signup and view all the answers

    What is the primary mechanism of phototherapy in treating neonatal jaundice?

    <p>Promote bilirubin excretion through urine</p> Signup and view all the answers

    Biliary atresia is a condition characterized by a complete obstruction of the bile ducts.

    <p>True</p> Signup and view all the answers

    Which of the following is a defect associated with Gilbert's Syndrome?

    <p>Reduced hepatic uptake of bilirubin</p> Signup and view all the answers

    Which of the following conditions is characterized by a total absence of UDP glucuronyltransferase?

    <p>Crigler-Najjar Syndrome (type 1)</p> Signup and view all the answers

    What is the primary characteristic of Lucy-Driscoll Syndrome?

    <p>Defective bilirubin conjugation</p> Signup and view all the answers

    Which of the following conditions is typically characterized by conjugated hyperbilirubinemia?

    <p>Dubin-Johnson Syndrome</p> Signup and view all the answers

    What is the primary difference between Dubin-Johnson Syndrome and Rotor Syndrome?

    <p>Dubin-Johnson Syndrome is associated with dark pigment in hepatocytes, while Rotor Syndrome is associated with cytosolic inclusion bodies.</p> Signup and view all the answers

    Which type of jaundice is typically associated with elevated levels of unconjugated bilirubin?

    <p>Prehepatic jaundice</p> Signup and view all the answers

    What is the primary mechanism of bilirubin elevation in hepatocellular jaundice?

    <p>Defective bilirubin conjugation</p> Signup and view all the answers

    Which of the following laboratory tests is most commonly used to assess the excretory function of the liver?

    <p>Serum bilirubin</p> Signup and view all the answers

    What is the primary mechanism of bilirubin elevation in posthepatic jaundice?

    <p>Obstruction of the biliary tree</p> Signup and view all the answers

    Which of the following is NOT a feature of prehepatic jaundice?

    <p>Abnormal prothrombin time</p> Signup and view all the answers

    What is the primary concern with an abnormally high level of unconjugated bilirubin in a newborn?

    <p>Risk of kernicterus</p> Signup and view all the answers

    What are the two common methods used for bilirubin analysis?

    <p>Chemical method (diazo reaction) and spectrophotometric method</p> Signup and view all the answers

    Spectrophotometry is a direct method for measuring bilirubin that relies on the absorbance of light at specific wavelengths.

    <p>True</p> Signup and view all the answers

    Which method of bilirubin analysis is typically considered the most accurate?

    <p>Chromatography (HPLC)</p> Signup and view all the answers

    A reagent blank is used to correct for potential error in test results that arise from the sample itself.

    <p>False</p> Signup and view all the answers

    Which of the following is NOT a reason to avoid hemolysis when collecting a sample for bilirubin analysis?

    <p>It can increase the risk of infection</p> Signup and view all the answers

    Study Notes

    Liver Function

    • Objectives: State physiologic liver functions, discuss lab tests, illustrate bilirubin metabolism, classify hyperbilirubinemia types and causes, explain lab methods for bilirubin determination, discuss liver disorders and appropriate tests for diagnosis, and differentiate hepatitis types.

    Hepatic Blood Supply

    • Hepatic artery (25%): Supplies oxygen and nutrients for liver metabolism, branching off the aorta with ~30% of total cardiac output directed to the liver.
    • Portal vein (75%): Part of portal hepatic system; connects gastrointestinal tract (GIT) capillaries to the liver; carries nutrient-rich blood.
    • Hepatic vein: Drains deoxygenated blood from the liver to the inferior vena cava (IVC), carrying nutrients produced by the liver and waste products.

    Normal Liver Function

    • Hepatocytes: Responsible for most metabolic reactions, including protein synthesis (all coagulation factors except vWF), carbohydrate metabolism, amino acid and nucleic acid metabolism, amino acid and dicarboxylic acid interconversions via transaminases, lipoprotein synthesis and metabolism, xenobiotic and drug metabolism, and iron and vitamins (A, D, and B12) storage.

    Liver Function Tests (LFTs)

    • Purpose: Screen for liver disease, identify disease type (e.g., hepatocellular, cholestatic), assess disease severity and prognosis, and monitor disease progression.
    • Limitations: LFTs are not specific, they may not always reflect liver function, and they may be normal in some liver diseases (like cirrhosis), they may also be abnormal in non-liver disorders.

    Bilirubin

    • Daily Production: 250-300 mg per day
    • Source: Breakdown of senescent red blood cells (85%) and haem-containing proteins (e.g., myoglobin, cytochromes, peroxidases) (15%)
    • Mechanism: Haem --> protoporphyrin IX (microsomal haem oxygenase) --> biliverdin IXa (biliverdin reductase) --> bilirubin IXa. It's then transported to the liver, bound to albumin, and enters hepatocytes where it's conjugated to glucuronic acid. This conjugated form is transported into bile canaliculi
    • Metabolism: In macrophages (mainly in the spleen), heme from red blood cells is broken down. Bilirubin is then transported to the liver bound to albumin and enters the hepatocytes where it's conjugated to glucuronic acid. Conjugated bilirubin is transported into bile canaliculi.

    Hyperbilirubinemia

    • Definition: Serum bilirubin levels exceeding 3 mg/dL.
    • Types:
      • Unconjugated: Pre-hepatic (e.g., hemolytic anemia), hepatic (e.g., impaired hepatic uptake or conjugation),
      • Conjugated: Hepatic (e.g. impaired secretion in bile) and post-hepatic (e.g., obstruction of the biliary tract).

    Inherited Disorders of Bilirubin Metabolism

    • Gilbert's syndrome: Reduced hepatic uptake of bilirubin, familial and autosomal recessive.
    • Crigler-Najjar syndrome (types 1 & 2): Complete or partial deficiency of UDP-glucuronyl transferase.
    • Type 1: Severe, potentially fatal in infancy due to very high unconjugated bilirubin levels (often >20 mg/dL).
    • Type 2: Less severe, with fluctuating unconjugated bilirubin levels typically < 20 mg/dL.
    • Lucey-Driscoll syndrome: Circulating inhibitor of bilirubin conjugation resulting in mild unconjugated hyperbilirubinemia.
    • Dubin-Johnson syndrome: Defective canalicular excretion of conjugated bilirubin.
    • Rotor syndrome: Impaired hepatocellular storage of conjugated bilirubin.

    Neonatal Jaundice

    • Physiological jaundice: Common in newborns, peaking within 1-7 days after birth and resolving within 2 weeks. Associated with immature liver function and/or increased bilirubin load.
    • Pathological jaundice: Serum bilirubin levels exceeding thresholds or appearing early (often within the first 24 hours of life) could indicate a serious pathology needing urgent medical attention.

    Analytical Methods for Bilirubin

    • Methods: Several methods exist, including chemical (diazo reaction), direct spectrophotometry, and reflectance photometry.
    • Sampling: Fasting serum or plasma samples, protected from light, collected using appropriate techniques (no hemolysis)
    • Important considerations: Factors like haemolysis or interference from other pigments, which can alter results, need to be taken into account.
    • Reference methods: High-performance liquid chromatography (HPLC) is often used as a reference standard.

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    Liver Function PDF - 2024

    Description

    Test your knowledge on liver physiology and blood supply with this quiz. You'll explore liver functions, bilirubin metabolism, and the different types of hepatitis. Additionally, the quiz touches on laboratory tests relevant to diagnosing liver disorders.

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