Hepatic intro

Question 1

2. Where is the liver located and what are its key anatomical characteristics?

Answer 1

• Located in the right upper quadrant of the abdomen
• Largest internal organ
• Weighs about 1.5 kg in healthy adults
• Size may increase in diseases such as cirrhosis
• Divided into two main lobes

Question 2

3. What is the functional unit of the liver?

Answer 2

• The liver lobule
• Lobules are arranged in hexagonal patterns
• They repeat throughout the liver tissue

Question 3

4. What are the key components of the liver blood supply?

Answer 3

• Hepatic portal vein (75%)
• Hepatic artery (25%)
• Allows nutrient-rich blood from digestive organs and oxygenated blood from the heart

Question 4

5. What is the role of the hepatic artery?

Answer 4

• Delivers oxygenated blood directly from the heart to the liver

Question 5

6. What is the role of the hepatic portal vein?

Answer 5

• Carries nutrient-rich blood from digestive organs
• Allows the liver to process nutrients absorbed from the intestine

Question 6

7. What are sinusoids?

Answer 6

• Specialised blood channels within liver lobules
• Blood filters through sinusoids
• Hepatocytes interact with substances in the blood during this process

Question 7

8. How does blood exit the liver?

Answer 7

• Sinusoids
• Central veins
• Hepatic veins
• Blood returns to systemic circulation

Question 8

9. What are the five main functions of the liver?

Answer 8

• Metabolic
• Clearance (detoxification)
• Synthetic
• Immunological
• Storage

Question 9

10. What metabolic functions does the liver perform?

Answer 9

• Processes carbohydrates, proteins, fats and steroid hormones

Question 10

11. What is the clearance function of the liver?

Answer 10

• Detoxifies and eliminates drugs, bilirubin and toxins

Question 11

12. What are the synthetic functions of the liver?

Answer 11

• Produces albumin
• Produces clotting factors
• Produces other vital plasma proteins

Question 12

13. What is the immunological function of the liver?

Answer 12

• Kupffer cells remove pathogens, toxins and debris from blood

Question 13

14. What storage functions does the liver perform?

Answer 13

• Stores vitamins
• Stores glucose
• Stores minerals

Question 14

15. What is albumin?

Answer 14

• Major plasma protein produced by the liver

Question 15

16. What is the primary physiological role of albumin?

Answer 15

• Maintains oncotic pressure
• Keeps fluid inside blood vessels
• Prevents oedema formation

Question 16

17. Why is albumin important for plasma oncotic pressure?

Answer 16

• Albumin concentration is the primary contributor to plasma oncotic pressure

Question 17

18. How does albumin maintain fluid balance?

Answer 17

• Creates osmotic gradient
• Pulls water into bloodstream
• Counteracts hydrostatic pressure pushing fluid out of vessels

Question 18

19. What transport functions does albumin perform?

Answer 18

• Carries drugs
• Carries hormones
• Carries metabolites through circulation

Question 19

20. What drugs bind to albumin?

Answer 19

• Warfarin
• Aspirin
• Ibuprofen

Question 20

21. What lipid metabolism functions occur in the liver?

Answer 20

• Synthesises cholesterol
• Produces phospholipids
• Produces lipoproteins for fat transport

Question 21

22. What vitamin storage functions occur in the liver?

Answer 21

• Stores vitamins A, D, E, K
• Stores vitamin B12

Question 22

23. What role does the liver play in vitamin D metabolism?

Answer 22

• Converts vitamin D into its active form
• Important for calcium balance

Question 23

24. What protein metabolism functions occur in the liver?

Answer 23

• Deamination
• Transamination
• Synthesises non‑essential amino acids

Question 24

25. What carbohydrate metabolism functions occur in the liver?

Answer 24

• Maintains blood glucose levels
• Glycogenolysis
• Gluconeogenesis
• Stores glycogen

Question 25

26. How much glycogen can the liver store?

Answer 25

- Up to 100 g glycogen - Acts as an energy reserve

Question 26

27. What are metabolic intermediates produced during carbohydrate metabolism?

Answer 26

- Compounds formed from carbohydrate breakdown used to produce other molecules

Question 27

28. What sugars can the liver convert into glucose?

Answer 27

- Galactose - Fructose

Question 28

29. What is gluconeogenesis?

Answer 28

- Production of glucose from non‑carbohydrate sources - Example: amino acids

Question 29

30. How does bilirubin metabolism begin?

Answer 29

- Red blood cells break down - Haemoglobin converted to unconjugated bilirubin

Question 30

31. How is bilirubin transported to the liver?

Answer 30

- Albumin carries bilirubin in the blood

Question 31

32. What happens during bilirubin conjugation?

Answer 31

- Liver converts bilirubin into water‑soluble conjugated form

Question 32

33. How is bilirubin eliminated?

Answer 32

- Secreted into bile - Eliminated via intestines

Question 33

34. What are bile canaliculi?

Answer 33

- Tiny channels between hepatocytes - Collect bile produced by liver cells

Question 34

35. What are bile ducts?

Answer 34

- Canaliculi merge to form progressively larger bile ducts

Question 35

36. What is the common hepatic duct?

Answer 35

- Formed from merger of right and left hepatic ducts

Question 36

37. What is the role of the cystic duct and gallbladder?

Answer 36

- Gallbladder stores and concentrates bile between meals

Question 37

38. What is the function of the common bile duct?

Answer 37

- Delivers bile to duodenum for fat digestion

Question 38

39. What reactions occur in Phase I metabolism?

Answer 38

- Oxidation (primary) - Reduction - Hydrolysis

Question 39

40. Which enzymes perform Phase I metabolism?

Answer 39

- Cytochrome P450 enzymes

Question 40

41. What chemical changes occur during Phase I metabolism?

Answer 40

- Addition/exposure of polar groups (-OH, -SH, -NH2) - Increases water solubility

Question 41

42. How does ageing affect Phase I metabolism?

Answer 41

- Elderly patients show reduced Phase I metabolism - Drugs have longer half‑lives

Question 42

43. Why is Phase I metabolism clinically important?

Answer 42

- Many metabolites remain pharmacologically active - Dose adjustments may be needed

Question 43

44. What is the evolutionary role of CYP450 enzymes?

Answer 43

- Protect organisms from lipophilic compounds - Important survival detoxification system

Question 44

45. What endogenous molecules are metabolised by CYP450?

Answer 44

- Steroid hormones

Question 45

46. Where are CYP450 enzymes located?

Answer 45

- Membrane‑bound proteins - Embedded in phospholipid membrane - Contain iron haem group

Question 46

47. What is the main activity of CYP450 enzymes?

Answer 46

- Primary enzymes responsible for xenobiotic metabolism - Carry out oxidation reactions

Question 47

48. What is a substrate in CYP450 metabolism?

Answer 47

- Drug or molecule that binds to CYP450 enzyme to be metabolised

Question 48

49. What are enzyme inducers?

Answer 48

- Increase CYP450 enzyme production - Accelerate metabolism - Reduce drug efficacy

Question 49

50. What are enzyme inhibitors?

Answer 49

- Reduce CYP450 activity - Increase drug levels - Increase toxicity risk

Question 50

51. What characterises high extraction ratio drugs?

Answer 50

- Blood‑flow limited - Extensive first‑pass metabolism - Examples: propranolol, morphine

Question 51

52. What characterises low extraction ratio drugs?

Answer 51

- Capacity limited - Minimal first‑pass effect - Examples: warfarin, phenytoin

Question 52

53. Example MCQ: Drug that binds CYP450 to be metabolised is called?

Answer 52

- Correct answer: Substrate

Question 53

54. Example SAQ: Two overarching liver functions and example

Answer 53

- Metabolic: carbohydrate metabolism (glycogenolysis, gluconeogenesis) - Synthetic: albumin production maintaining oncotic pressure and transport