Pancreatic and Bile Secretion Flashcards Preview

Physiology and Neuroscience > Pancreatic and Bile Secretion > Flashcards

Flashcards in Pancreatic and Bile Secretion Deck (49):
1

Describe the liver

Largest gland in the body
Produces bile
Comprises 4 lobes

2

What are liver lobules?

Hexagonal structural and functional units
Filter and process nutrient-rich blood
Composed of plates of hepatocytes (liver cells) • Longitudinal central vein

3

What is the portal vein?

Blood from small intestine that goes through the liver because liver breaks down anything toxic from small intestine

4

Where are the bile ducts?

Around the edges of the liver

5

Where does blood come into the liver?

Through portal vein into lobule, passes by hepatocytes

6

What are sinusoids?

Canals moving in between hepatocytes, substances can go in and out of them

7

What happens once blood has been passed through the sinusoid?

Once cleaned it goes into the central vein and then into the hepatic vein

8

What are hepatocytes involved in?

Bile production

9

What is the process of making bile?

Hepatocytes->bile canaliculi (passageways move in between hepatocytes, gather up bile)->bile ductules->bile ducts

10

What does a hepatocyte look like

Sinusoidal Blood
Apical membrane tight junction, connected to "basolateral membrane"
Sinusoidal blood

11

How much bile is produced per day?

800-1000mL

12

What is the pH of bile?

7.6-8.6

13

What does bile contain?

Bile salts
Bilirubin
Cholestrol, neutral fats, phospholipids, and electrolytes

14

What are the functions of bile?

Lipid assimilation
Elimination
Neutralise gastric acid and provide optimum pH for pancreatic enzymes

15

What are bile salts?

Cholesterol derivatives that function in fat

16

What are the bile ducts?

Right and left hepatic ducts of liver
Cystic duct
Common hepatic duct
Bile duct and sphincter
Accessory pancreatic duct
Main pancreatic duct and sphincter
Hepatopancreatic ampulla and sphincter

17

Where is the main pancreatic duct?

In the pancreas heading towards the tail of the pancreas

18

Where is the Hepatopancreatic ampulla and sphincter?

Between the pancreas and the duodenum

19

What is the appearance of the gallbladder?

Thin walled, pear-shaped, muscular sac on the ventral surface of the liver

20

What is the function of the gallbladder?

Stores and concentrates bile by absorbing its water and ions

21

What does the gallbladder release?

Bile via the cystic duct which flows into the bile duct

22

What are gallstones also called?

Cholelithiasis

23

What do gallstones account for?

95% of biliary tract disease

24

How are gallstones formed?

Form if bile contains insufficient bile salts or excessive cholestrol

25

What does cholestrol do to form gallstones?

Crystallises

26

How are gallstones treated?

With drugs, lithotripsy or surgery

27

What is bile secretion regulated by?

Bile salts in enterohepatic circulation
Secretin from intestinal cells exposed to HCL and fatty chyme

28

What is gallbladder contraction stimulated by?

Cholecystokinin (CCK) from intestinal cells exposed to proteins and fat in chyme
Vagal stimulation (minor stimulus)

29

What does CKK cause?

The heptopancreatic sphincter to relax

30

What is the pancreas endocrine functions?

Pancreatic islets secrete insulin and glucagon

31

What is the pancreas exocrine functions?

Acini (clusters of secretory cells) secrete pancreatic juice
Zymogen granules of secretory cells contain digestive enzymes

32

How much pancreatic juice is produced?

1200-1500mL per day

33

What does pancreatic juice contain?

Electrolytes (primarily HCO3-)
Enzymes

34

What are the pancreatic enzymes?

Amylase, lipases, nucleases are secreted in active form but require ions or bile for optimal activity

35

What happens when proteases is secreted?

Secreted in inactive form and activated in duodenum

36

What is trypsinogen activated to?

Trypsin

37

What is trypsinogen activated by?

Brush border enzymes

38

What does trypsin activate?

Procarboxypeptidase and chymotrypsinogen

39

What does CCK induce?

The secretion of enzyme-rich pancreatic juice by acini

40

What does secretin cause?

Secretion of bicarbonate-rich pancreatic juice

41

What also causes the release of pancreatic juice?

Vagal stimulation

42

What does chyme entering the duodenum cause?

Release of cholecystokinin (CCK) and secretin from duodenal enteroendocrine cells

43

Where are CCK and secretin released into?

Bloodstream

44

What does CCK induce?

Secretion of enzyme-rich pancreatic juice

45

What does secretin cause?

Secretion of HCO3- rich pancreatic juice

46

What stimulates the liver to produce bile more rapidly?

Bile salts and to a lesser extent secretin

47

What does CCK cause?

Gallbladder to contract and hepatopancreatic sphincter to relax; bile enters duodenum

48

What causes weak contractions of gallbladder?

During cephalic and gastric phases, vagal nerve stimulation

49

What is the portal triad?

Portal vein
Hepatic artery
Bile duct