Topic 5 Digestive System: Liver Functions

Question 1

• Liver receives blood from capillary beds of intestines, stomach, spleen, and pancreas via hepatic portal vein -> liver “works on” this blood
• Liver is oxygenated by a second blood supply (via hepatic artery_
• All blood received from liver -> flattened hepatic sinusoids -> hepatic vein -> vena cave

Answer 1

Note

Question 2

1. Blood Storage
2. Blood Filtration
3. Carbohydrate Metabolism
4. Fat Metabolism
5. Protein Metabolism
6. Detoxification
7. Erythrocyte Destruction
8. Vitamin Storage
9. Glycogenesis
10. Glycogenolysis
11. Digestive function
12. Transportation function

Answer 2

Liver Functions

Question 3

• Kupfer cells (specialized macrophages in liver) phagocytize bacteria picked up in intestine

Answer 3

Blood filtration

Question 4

• liver maintains normal blood glucose levels via gluconeogenesis (production of glycogen and glucose from noncarbohydrate precursors), glycogenesis, and storage of glycogen (not glucose, it stores as glycogen)
  a. All carbohydrates absorbed into blood are carried by portal vein to the liver
  b. Absorbed galactose + fructose converted to glucose, then stored as glycogen

Answer 4

3. Carbohydrate Metabolism

Question 5

• liver synthesizes bile from cholesterol and converts carbohydrates and proteins -> fat. Fat metabolism oxidizes fatty acids for energy, and also forms lipoproteins

Answer 5

4. Fat Metabolism

Question 6

• liver deaminates amino acids, forms urea from ammonia in blood, synthesizes plasm proteins and nonessential amino acids
  a. Urea: major end product of nitrogen metabolism and is produced here and later transported to kidneys for excretion

Answer 6

5. Protein Metabolism

Question 7

• detoxifies chemicals which are then excreted by liver as part of bile (or polarized to be excreted by kidneys)

Answer 7

6. Detoxification

Question 8

• Kupfer cells destroy irregular erythrocytes (but most are destroyed by spleen)

Answer 8

7. Erythrocyte Destruction

Question 9

• stores vitamin A, D, and B12. Liver also stores iron by combining it with apoferritin -> ferritin

Answer 9

8. Vitamin Storage

Question 10

• formation of glycogen

Answer 10

9. Glycogenesis

Question 11

• if blood glucose levels decrease -> glycogen broken down to glucose for release

Answer 11

10. Glycogenolysis

Question 12

• Produces bile

Answer 12

11. Digestive Function

Question 13

• synthesizes blood plasma proteins like albumin, which is important in clotting

Answer 13

12. Transportation Function

Question 14

• When the liver mobilizes fat or protein for energy, blood acidity increases (ketone bodies are produced → ketosis/acidosis results)
• Liver malfunction can lead to jaundice, yellow pigmentation from excess bilirubin (a byproduct of erythrocyte breakdown). Liver malfunction also fails to remove bilirubin, so it builds up in the blood

Answer 14

Note