Pancreas and Liver

Question 1

Explain why gastric release to duodenum must be controlled. (3)

Answer 1

Chyme emerges from the stomach hypotonic but cannot be dilutes because the stomach wall is impermeable to water.
When it reaches the duodenum, water moves in through the permeable duodenal wall.
Chyme release must be controlled to avoid the sudden influx of water from overwhelming the duodenum.

Question 2

Describe what the duodenum prompts to be released. (2)

Answer 2

Secretin and CCK to encourage pancreatic HCO3- and release bile into the duodenum.

Question 3

Describe the structure of the pancreas and what each cell type does. (3)

Answer 3

Acinar cells containing zygomen granules: store and release inactive proteases and other enzymes eg lipase, amylase.
Duct cells: release Aq HCO3-

Question 4

Describe what makes up bile. (3)

Answer 4

Bile acids, bile pigments and alkaline solution.

Question 5

Describe the 4 lobes of the liver.

Answer 5

Left
Right
Caudate - anteroinferior - next to IVC
Quadrate - posteroinferior - next to gallbladder.

Question 6

Describe the structure of a liver lobule. (5)

Answer 6

Portal veins, hepatic arteries and bile ducts around the edge, central vein centrally.
Hepatocyte cells surrounding sinusoid spaces containing Kupffer cells. Blood flows inwards, bile flows outwards unto bile duct into duodenum.

Question 7

Describe the zone system of a liver acinus. (3)

Answer 7

Zone system used to mark distance from arterial blood supply.
Area 1 is closest to the artery so is vulnerable to toxin damage.
Area 3 is furthest from the artery so is vulnerable to ischaemia.

Question 8

Explain the production of bile salts. (2)

Answer 8

Bile acid + amino acid = bile salt. Salts are amphipathic so are more soluable.

Question 9

Explain the purpose of bile salts. (4)

Answer 9

Emulsify fats into smaller droplets for larger SA for lipase action. Also form micelles with the products of lipid digestion (cholesterol, fatty acids).
These micelles diffuse into the intestinal epithelial cells but bile salts remain for reabsorption in terminal ileum and returning to the liver through the portal vein.

Question 10

Describe the development of the pancreas. (3)

Answer 10

Develops as a dorsal and ventral bud on the opposite sides of thside duodenum. It rotates, pulling the buds together and pulling the biliary tree around it.