Question 1

A breakdown product of bilirubin metabolism that is produced in the colon from the oxidation of urobilinogen by microorganisms is:&#10;A) Porphobilinogen.&#10;B) Urobilin.&#10;C) Stercobilinogen.&#10;D) Protoporphyrin.&#10;E) Protoheme.

Accepted Answer

Urobilin is a breakdown product of bilirubin metabolism, formed in the colon from the oxidation of urobilinogen by microorganisms.

Question 2

The enzyme system that catalyzes the conjugation of bilirubin is known as:&#10;A) Leucine aminopeptidase.&#10;B) Glucose-6-phosphate dehydrogenase.&#10;C) Uridine diphosphate (UDP) glucoronyl transferase.&#10;D) Carbamyl phosphate synthetase.&#10;E) Lactate dehydrogenase.

Accepted Answer

Uridine diphosphate (UDP) glucoronyl transferase is the enzyme system responsible for catalyzing the conjugation of bilirubin, making it more water-soluble for excretion.

Question 3

The cells that make up 70% of the liver's mass are:&#10;A) Kupffer cells.&#10;B) Hepatocytes.&#10;C) Endothelial cells.&#10;D) None of the above.

Accepted Answer

Hepatocytes are the primary functional cells of the liver, making up about 70-85% of the liver's mass. They play a crucial role in metabolism, detoxification, and protein synthesis.

Question 4

Which of the statements regarding bilirubin metabolism is TRUE?&#10;A) It is a product of porphyrin metabolism.&#10;B) It is reduced to biliverdin before excretion.&#10;C) It is produced from the destruction of RBCs.&#10;D) It is formed by the hydrolysis of the ?-methene bridge of urobilingen.

Accepted Answer

Bilirubin is produced from the breakdown of hemoglobin during the destruction of red blood cells (RBCs).

Question 5

Which is a characteristic of unconjugated bilirubin?&#10;A) It is water-soluble.&#10;B) It reacts faster than conjugated bilirubin.&#10;C) It has the same absorbance properties as conjugated bilirubin.&#10;D) It a not water-soluble.

Accepted Answer

Unconjugated bilirubin is not water-soluble. It is lipid-soluble and requires conjugation in the liver to become water-soluble (conjugated bilirubin) for excretion into the bile.

Question 6

The term ?-bilirubin (delta) refers to:&#10;A) Water-soluble bilirubin.&#10;B) Free unconjugated bilirubin.&#10;C) Bilirubin tightly bound to albumin.&#10;D) Direct-reacting bilirubin.

Accepted Answer

Delta bilirubin refers to bilirubin that is tightly bound to albumin. This form of bilirubin is not easily removed from the bloodstream and can persist even after other forms of bilirubin decrease.

Question 7

Kernicterus is the abnormal accumulation of bilirubin in:&#10;A) Heart tissue.&#10;B) Brain tissue.&#10;C) Liver tissue.&#10;D) Kidney tissue.&#10;E) Blood.

Accepted Answer

Kernicterus is a condition where there is an abnormal accumulation of bilirubin in the brain tissue, leading to neurological damage.

Question 8

What is the most common cause of unconjugated hyperbilirubinemia?&#10;A) Hemolytic anemia&#10;B) Gilbert's disease&#10;C) Bile duct obstruction&#10;D) Dubin-Johnson&#10;E) Neonatal physiologic jaundice

Accepted Answer

Neonatal physiologic jaundice is the most common cause of unconjugated hyperbilirubinemia due to the immature liver enzyme systems in newborns.

Question 9

Which of the following would be classified as prehepatic jaundice?&#10;A) Hepatitis&#10;B) Congestive heart failure&#10;C) Rotor syndrome&#10;D) Cancer of the bile ducts

Accepted Answer

Prehepatic jaundice is caused by conditions that lead to an increased breakdown of red blood cells, which results in an overload of bilirubin in the blood before it reaches the liver. Congestive heart failure can lead to prehepatic jaundice due to increased hemolysis associated with blood congestion. Hepatitis and cancer of the bile ducts are causes of hepatic and posthepatic jaundice, respectively, due to liver damage and bile duct obstruction. Rotor syndrome is a rare, inherited disorder that affects the liver's ability to process bilirubin, but it is not a prehepatic cause.

Question 10

In obstructive liver disease, the following test results are found:&#10;A) Feces: urobilinogen decreased; urine: bilirubin: positive; serum: conjugated bilirubin increased.&#10;B) Feces: urobilinogen decreased or negative; urine: urobilinogen decreased or negative; serum: conjugated bilirubin decreased.&#10;C) Feces: urobilinogen increased; urine: bilirubin: normal; serum: conjugated bilirubin normal or slightly elevated.&#10;D) None of the above.

Accepted Answer

In obstructive liver disease, the bile ducts are blocked, preventing bile (and thus bilirubin) from reaching the intestines. This results in decreased fecal urobilinogen (since bilirubin is not reaching the intestines to be converted into urobilinogen), positive urine bilirubin (as conjugated bilirubin is excreted in the urine due to the blockage), and increased serum conjugated bilirubin (since it cannot be excreted into the intestines).

Question 11

The reagent (accelerator) in the Jendrassik-Grof bilirubin procedure that makes indirect bilirubin water-soluble is:&#10;A) Hydrochloric acid.&#10;B) Caffeine.&#10;C) Methanol.&#10;D) Alkaline tartrate.

Accepted Answer

The answer of The reagent (accelerator) in the Jendrassik-Grof bilirubin...

Question 12

If a total bilirubin is 4.0 mg/dL and the conjugated bilirubin is 2.5 mg/dL, the unconjugated bilirubin is:&#10;A) 1.0 mg/dL.&#10;B) 1.5 mg/dL.&#10;C) 2.0 mg/dL.&#10;D) 3.0 mg/DldL.

Accepted Answer

The answer of If a total bilirubin is 4.0 mg/dL...

Question 13

In the Jendrassik-Grof bilirubin, what converts purple azobilirubin to blue azobilirubin measured at 600nm?&#10;A) Hydrochloric acid&#10;B) Caffeine&#10;C) Methanol&#10;D) Alkaline tartrate

Accepted Answer

The answer of In the Jendrassik-Grof bilirubin, what converts purple...

Question 14

Viral hepatitis that results in the largest percentage of chronic hepatitis is:&#10;A) Hepatitis A.&#10;B) Hepatitis B.&#10;C) Hepatitis C.&#10;D) Hepatitis D.

Accepted Answer

The answer of Viral hepatitis that results in the largest...

Question 15

The two most significant sources of error in accurate ammonia determinations are sample handling and:&#10;A) Short shelf life of test reagents.&#10;B) Inability to automate the test procedure.&#10;C) Need for age-dependent reference ranges.&#10;D) Ammonia contamination in the laboratory.

Accepted Answer

The answer of The two most significant sources of error...

Question 16

The following disease is a recessive disorder of copper metabolism, which results in the accumulation of copper in the liver. A) Hereditary hemochromatosis B) Wilson's disease C) ?₁-antitrypsin D) Gilbert's disease

Accepted Answer

The answer of The following disease is a recessive disorder...

Question 17

An autosomal recessive disorder of iron metabolism, which is characterized by excessive iron absorption and accumulation in various tissues in the body, is termed: A) Hereditary hemochromatosis. B) Wilson's disease. C) ?₁-antitrypsin. D) Dubin-Johnson.

Accepted Answer

The answer of An autosomal recessive disorder of iron metabolism,...

Question 18

A Model for End-Stage Liver disease staging system to predict prognosis in cirrhosis uses the following laboratory determinations EXCEPT:&#10;A) Bilirubin.&#10;B) INR.&#10;C) Creatinine.&#10;D) Aspartate transaminase.

Accepted Answer

The answer of A Model for End-Stage Liver disease staging...

Question 19

Nonalcoholic steatohepatitis is characterized by all of the following EXCEPT:&#10;A) Necroinflammatory liver disease associated with accumulation of fat in the liver.&#10;B) AST greater than ALT.&#10;C) Consumption of less than 20g of ethanol daily.&#10;D) No inflammation or scarring of the liver.

Accepted Answer

The answer of Nonalcoholic steatohepatitis is characterized by all of...

Deck 19: Liver