LE 2: Liver Flashcards
What percentage of cardiac output does the liver receive?
A) 10%
B) 20%
C) 30%
D) 40%
C) 30%
Rationale: The liver receives approximately 30% of the cardiac output.
Which vessel supplies oxygenated blood to the liver?
A) Portal vein
B) Hepatic vein
C) Hepatic artery
D) Inferior vena cava
C) Hepatic artery
Rationale: The hepatic artery supplies oxygenated blood from the heart to the liver.
Which vessel carries nutrient-rich blood from the gut to the liver?
A) Hepatic artery
B) Hepatic vein
C) Portal vein
D) Superior vena cava
C) Portal vein
Rationale: The portal vein carries blood directly from the gut to the liver.
Which of the following is NOT a function of the liver?
A) Gluconeogenesis
B) Production of insulin
C) Deamination
D) Bilirubin conjugation
B) Production of insulin
Rationale: The liver does not produce insulin. Insulin is produced by the pancreas.
Which process involves the removal of the amino group from amino acids?
A) Glycolysis
B) Deamination
C) Oxidation
D) Methylation
B) Deamination
Rationale: Deamination is the process of removing the amino group from amino acids.
Which clotting factor is NOT produced by the liver?
A) II
B) V
C) VIII
D) X
C) VIII
Rationale: The liver produces several clotting factors, but factor VIII is not one of them.
Which vitamin is NOT stored in the liver?
A) Vitamin A
B) Vitamin C
C) Vitamin D
D) Vitamin K
B) Vitamin C
Rationale: The liver stores vitamins A, D, K, B12, and folate, but not vitamin C.
What is the primary storage form of glucose in the liver?
A) Glucose
B) Fructose
C) Glycogen
D) Galactose
C) Glycogen
Rationale: Glycogen is the storage form of glucose in the liver.
Which enzyme breaks down certain drugs and neurotransmitters in the liver?
A) Lipase
B) Amylase
C) Plasma cholinesterases
D) Catalase
C) Plasma cholinesterases
Rationale: Plasma cholinesterases are enzymes in the liver that break down certain drugs and neurotransmitters.
Which process transforms drugs in the liver to make them more water-soluble?
A) Deamination
B) Glycolysis
C) Conjugation
D) Hydrolysis
C) Conjugation
Rationale: Conjugation is one of the processes in the liver that transforms drugs to make them more water-soluble.
Which mineral is stored in the liver?
A) Calcium
B) Iron
C) Magnesium
D) Potassium
B) Iron
Rationale: The liver stores essential minerals like iron and copper.
Which of the following is a function of bile acids synthesized by the liver?
A) Blood clotting
B) Digestion and absorption of fats
C) Production of energy
D) Regulation of blood pressure
B) Digestion and absorption of fats
Rationale: Bile acids aid in the digestion and absorption of fats.
Which protein synthesized by the liver maintains osmotic balance in the blood?
A) Hemoglobin
B) Collagen
C) Albumin
D) Myoglobin
C) Albumin
Rationale: Albumin plays a role in maintaining osmotic balance in the blood.
Which process in the liver forms glucose from non-carbohydrate sources?
A) Glycogenesis
B) Glycolysis
C) Gluconeogenesis
D) Glycosylation
C) Gluconeogenesis
Rationale: Gluconeogenesis is the formation of glucose from non-carbohydrate sources.
Which of the following is NOT a synthetic function of the liver?
A) Production of clotting factors
B) Synthesis of bile acids
C) Conversion of ammonia to urea
D) Synthesis of albumin
C) Conversion of ammonia to urea
Rationale: Conversion of ammonia to urea is a metabolic function of the liver, not a synthetic function.
Which clotting factor is produced by the liver and is also known as prothrombin?
A) II
B) V
C) VII
D) X
A) II
Rationale: Factor II is also known as prothrombin.
Which process in the liver makes bilirubin water-soluble?
A) Oxidation
B) Reduction
C) Conjugation
D) Hydrolysis
C) Conjugation
Rationale: Conjugation of bilirubin in the liver makes it water-soluble.
Which of the following is a primary function of the liver in relation to fats?
A) Synthesis of fatty acids
B) Breakdown of triglycerides and cholesterol
C) Production of lipase enzyme
D) Storage of fatty acids
B) Breakdown of triglycerides and cholesterol
Rationale: The liver plays a role in the metabolism of triglycerides and cholesterol.
Which vessel drains blood out of the liver?
A) Hepatic artery
B) Hepatic vein
C) Portal vein
D) Superior vena cava
B) Hepatic vein
Rationale: The hepatic vein drains blood out of the liver and into the inferior vena cava.
Which of the following substances is transformed from lipid to water-soluble in the liver?
A) Oxygen
B) Carbon dioxide
C) Drugs
D) Water
C) Drugs
Rationale: The liver transforms drugs from lipid-soluble to water-soluble forms to aid in their excretion.
Which enzyme is responsible for oxidation and reduction in Phase 1 drug metabolism?
A) Hemoglobin
B) Cytochrome P450
C) Myoglobin
D) Lysozyme
B) Cytochrome P450
Rationale: Cytochrome P450 performs oxidation and reduction reactions, which are part of Phase 1 drug metabolism.
Where is Cytochrome P450 primarily located?
A) Cytoplasm
B) Mitochondria
C) Cell membrane
D) Nucleus
B) Mitochondria
Rationale: CYP enzymes are primarily found in the mitochondria of liver cells.
What characteristic feature does Cytochrome P450 have?
A) Absorbs light at 450 nm when exposed to oxygen
B) Absorbs light at 450 nm when exposed to carbon monoxide
C) Absorbs light at 500 nm when exposed to carbon dioxide
D) None of the above
B) Absorbs light at 450 nm when exposed to carbon monoxide
Rationale: Cytochrome P450 contains a heme pigment that absorbs light at a wavelength of 450 nm when exposed to carbon monoxide.
Which of the following is NOT a major CYP protein in drug metabolism?
A) CYP1A2
B) CYP2C9
C) CYP4A7
D) CYP3A5
C) CYP4A7
Rationale: CYP1A2, CYP2C9, CYP2D6, CYP3A4, and CYP3A5 are the major CYP proteins involved in drug metabolism.
Which CYP enzyme metabolizes Codeine?
A) CYP2D6
B) CYP3A4
C) CYP1A2
D) CYP2C9
A) CYP2D6
Rationale: Codeine is a substrate of CYP2D6.
Which substance inhibits CYP3A4?
A) Quinidine
B) Methadone
C) Grapefruit juice
D) Lidocaine
C) Grapefruit juice
Rationale: Grapefruit juice is an inhibitor of CYP3A4.
What is the prevalence of ultrarapid metabolizers in the African or Ethiopian population?
A) 1-2%
B) 3.4-6.5%
C) 29%
D) 6%
Answer: C) 29%
Rationale: The prevalence of ultrarapid metabolizers in the African or Ethiopian population is 29%.
Which of the following drugs is a substrate of CYP3A4?
A) Bufuralol
B) Erythromycin
C) Desipramine
D) Codeine
Answer: B) Erythromycin
Rationale: Erythromycin is a substrate of CYP3A4.
Which enzyme is inhibited by Fluoxetine?
A) CYP2D6
B) CYP3A4
C) CYP1A2
D) CYP2C9
A) CYP2D6
Rationale: Fluoxetine is an inhibitor of CYP2D6.
Which of the following is an inducer of CYP3A4?
A) Quinidine
B) Methadone
C) Phenobarbital
D) Cimetidine
C) Phenobarbital
Rationale: Phenobarbital is an inducer of CYP3A4.
Which CYP enzyme is most crucial in drug metabolism?
A) CYP1A2
B) CYP2C9
C) CYP3A4
D) CYP2D6
C) CYP3A4
Rationale: CYP3A4 and CYP2D6 are the most crucial in drug metabolism, with CYP3A4 being one of the most important.
Which of the following reactions is NOT dependent on CYP450 enzymes in the liver?
A) Oxidation of dopamine
B) Hydrolysis of amides
C) Oxidation of Codeine
D) Reduction of Erythromycin
A) Oxidation of dopamine
Rationale: The liver carries out non-CYP450 dependent reactions, including the oxidation of dopamine.
Which substance is hydrolyzed in the liver and is NOT dependent on CYP450?
A) Lignocaine
B) Pethidine
C) Codeine
D) Nifedipine
A) Lignocaine
Rationale: Lignocaine undergoes hydrolysis of amides in the liver, which is a non-CYP450 dependent reaction.
Which of the following is NOT an inhibitor of CYP2D6?
A) Quinidine
B) Methadone
C) Ketoconazole
D) Cimetidine
C) Ketoconazole
Rationale: Ketoconazole is an inhibitor of CYP3A4, not CYP2D6.
Which of the following is an inhibitor of CYP3A4?
A) Lidocaine
B) Ritonavir
C) Bufuralol
D) Desipramine
B) Ritonavir
Rationale: Ritonavir is an inhibitor of CYP3A4.
Which population has a prevalence of ultrarapid metabolizers between 3.4-6.5%?
A) African or Ethiopian
B) Asian
C) African American
D) Hungarian
C) African American
Rationale: The prevalence of ultrarapid metabolizers in the African American population is between 3.4-6.5%.
Which of the following drugs is NOT a substrate of CYP2D6?
A) Bufuralol
B) Codeine
C) Nifedipine
D) Lidocaine
C) Nifedipine
Rationale: Nifedipine is a substrate of CYP3A4, not CYP2D6.
Which of the following is an inducer of CYP3A4?
A) Rifampin
B) Fluoxetine
C) Quinidine
D) Methadone
A) Rifampin
Rationale: Rifampin is an inducer of CYP3A4.
Which population has the lowest prevalence of ultrarapid metabolizers?
A) Asian
B) Greek
C) African or Ethiopian
D) Caucasian
A) Asian
Rationale: The prevalence of ultrarapid metabolizers in the Asian population is between 1.2-2%.
Which of the following is NOT a substrate of CYP3A4?
A) Nifedipine
B) Erythromycin
C) Desipramine
D) Testosterone
C) Desipramine
Rationale: Desipramine is a substrate of CYP2D6, not CYP3A4.
Which of the following is a substrate of CYP2D6?
A) Lidocaine
B) Nifedipine
C) Erythromycin
D) Midazolam
A) Lidocaine
Rationale: Lidocaine is a substrate of CYP2D6.
Which of the following is NOT an inhibitor of CYP3A4?
A) Ketoconazole
B) Erythromycin
C) Grapefruit juice
D) Methadone
D) Methadone
Rationale: Methadone is an inhibitor of CYP2D6, not CYP3A4.
Which of the following is an inhibitor of CYP2D6?
A) Quinidine
B) Ritonavir
C) Phenobarbital
D) Rifampin
A) Quinidine
Rationale: Quinidine is an inhibitor of CYP2D6.
Which of the following is NOT an inducer of CYP3A4?
A) Carbamazepine
B) Phenobarbital
C) Quinidine
D) Phenytoin
C) Quinidine
Rationale: Quinidine is an inhibitor of CYP2D6, not an inducer of CYP3A4.
Which of the following reactions is dependent on CYP450 enzymes in the liver?
A) Oxidation of dopamine
B) Hydrolysis of amides
C) Oxidation of Codeine
D) Reduction of Erythromycin
C) Oxidation of Codeine
Rationale: Codeine is a substrate of CYP2D6, which is a CYP450 enzyme.
Which of the following is a substrate of CYP3A4?
A) Lidocaine
B) Ritonavir
C) Bufuralol
D) Midazolam
D) Midazolam
Rationale: Midazolam is a substrate of CYP3A4.
Which of the following is NOT an inhibitor of CYP2D6?
A) Quinidine
B) Methadone
C) Grapefruit juice
D) Cimetidine
C) Grapefruit juice
Rationale: Grapefruit juice is an inhibitor of CYP3A4, not CYP2D6.
Which of the following is an inhibitor of CYP3A4?
A) Lidocaine
B) Ritonavir
C) Bufuralol
D) Desipramine
B) Ritonavir
Rationale: Ritonavir is an inhibitor of CYP3A4.
Which population has a prevalence of ultrarapid metabolizers of 6%?
A) Asian
B) Greek
C) African or Ethiopian
D) Caucasian
B) Greek
Rationale: The prevalence of ultrarapid metabolizers in the Greek population is 6%.
Which of the following is NOT a substrate of CYP3A4?
A) Nifedipine
B) Erythromycin
C) Desipramine
D) Testosterone
C) Desipramine
Rationale: Desipramine is a substrate of CYP2D6, not CYP3A4.
- Which enzyme is indicative of hepatocellular injury?
a) ALP
b) GGT
c) AST
d) Bilirubin
c) AST
Rationale: A rise in AST (and ALT) signals hepatocellular injury or death
ALT - Alanine transaminase
AST - Aspartase transaminase
Which condition is NOT a cause of hepatocellular injury pattern in LFTs?
a) Viral hepatitis
b) Wilson’s disease
c) Primary biliary cirrhosis
d) Alcoholic hepatitis
c) Primary biliary cirrhosis
Rationale: Primary biliary cirrhosis is associated with an obstructive pattern, indicated by a rise in ALP and GGT.