Alimentary System III - Liver, gallbladder, pancreas

Question 1

Does the gallbladder have endocrine function?

Answer 1

Nope. The liver and pancreas do, though.

Question 2

Which cells of the pancreas have exocrine function? Which cells have endocrine function?

Answer 2

Acinar and ductal cells have exocrine function. Islet cells have endocrine function.

Question 3

What two major exocrine products does the pancreas produce?

Answer 3

Bicarbonate and zymogens/enzymes

Question 4

Where does the pancreas - liver - gallbladder common duct empty?

Answer 4

Duodenum.

Question 5

What do pancreatic ductal cells secrete and for what purpose?

Answer 5

Alkaline fluid dilutes enzymes

Question 6

Where in the acinar cells of the pancreas can zymogen granules be seen?

Answer 6

At the apical end

Question 7

What are differences between an intralobular duct and interlobular duct? Describe the epithelial cell types.

Answer 7

Intralobular ducts are within the lobules and have simple cuboidal epithelium. Interlobular ducts lie between ducts and as they join up and get larger, the epithelium becomes columnar.

Question 8

What are the two major peptide hormones that control secretion of pancreatic enzymes? Where are they synthesized? What does each one do specifically?

Answer 8

Both released from duodenum. Cholecystokinin (CCK) causes release of zymogen granules from acinar cells. Secretin causes the intralobular ducts to secrete a bicarbonate-rich solution to dilute the enzymes.

Question 9

How does CCK and secretin affect the gallbladder?

Answer 9

CCK causes gallbladder muscularis propria contraction to empty the gallbladder.

Secretin stimulates bile duct cells to secrete aqueous solution for bile dilution.

Question 10

What causes pancreatitis?

Answer 10

Zymogen activation in the pancreas instead of in the duodenum. This leads to inflammation and can block ducts.

Question 11

How does CF cause pancreatic cysts?

Answer 11

Defective Cl- channel results in viscous bicarbonate secretions that can block the ducts, leading to cyst formation.

Question 12

What two important structures are associated with pancreatic islet cells?

Answer 12

1. Recicular CT for support

2. Fenestrated capillaries into which hormones are secreted

Question 13

What are three major pancreatic endocrine cell types and what do they do?

Answer 13

• Aplha cells make glucagon.
• Beta cells make insulin (majority of the mass of islet cells).
• Delta cells make somatostatin, which suppresses alpha and beta cell hormone secretion.

Question 14

What are two endocrine functions of the liver?

Answer 14

1. Maintain optimal concentrations of various blood components.
2. Process the blood it receives from digestion via the hepatic portal vein.

Question 15

What are hepatic portal triads?

Answer 15

Where the branches of the hepatic artery/portal vein/bile ducts branch between the classic liver lobules.

Question 16

What is a hepatic portal lobule?

Answer 16

A triangle drawn amongst three adjacent central veins.

Question 17

What is a hepatic acinus?

Answer 17

A diamond shaped structure that has a central axis connecting two portal triads, and extends outwards to two central veins.

Question 18

Are zone 1 acinar cells (in the liver) closest or furthest from the blood supply? What oxidative functions do they perform?

Answer 18

They are closest to the blood. They perform gluconeogenesis, cholesterol synthesis.

Question 19

Which hepatic acinar cells are the first to show ischemic necrosis and fat accumulation? (note: these cells are also sensitive to acetaminophen)

Answer 19

Zone 3 acinar cells.

Question 20

Where are bile canaliculi found?

Answer 20

Between liver hepatocytes (where they touch each other)

Question 21

Describe the surface of a hepatocyte that faces a sinusoid.

Answer 21

Microvilli.

Question 22

What is a space of Disse?

Answer 22

The space between a hepatocyte and the fenestrated endothelial cells of a sinusoid.

Question 23

Does the space of Disse contain CT and basement membrane material?

Answer 23

Nope. It DOES have reticular fibers, though.

Question 24

What are Kupffer cells and where are they found? What do they do?

Answer 24

They are macrophages (monocyte derivatives) attached to the lumenal surface of hepatocytes. They phagocytize particulates, gut pathogens, and senescent RBCs.

Question 25

What does the gallbladder do?

Answer 25

Stores and concentrates bile.

Question 26

Describe the gallbladder mucosa.

Answer 26

Tall columnar cells, with underlying lamina propria. Can be folded heavily and can look like intestinal mucosa.

Question 27

How does one differentiate gallbladder mucosa from intestinal mucosa?

Answer 27

Gallbladder mucosa has NO goblet cells, NO crypts, NO muscularis mucosae, and an unorganized muscularis externa with interspersed CT and elastic fibers.

Question 28

What two apical surface specializations are found on cholecystocytes? What is unique about the lower lateral surface of these cells?

Answer 28

Zonula occludens and adherens. During ion and water transport, the lower lateral regions can separate.

Question 29

What covers the outside of the gallbladder?

Answer 29

Serosa (except where it attaches to the liver by adventitia)