Pancreas and Liver

Question 1

What is the role of the exocrine pancreas and liver

Answer 1

provide excretions (digestive enzymes) directly into intestine lumen, to digest CHO, protein, lipid in small intestine.

Question 2

What is role of the Endocrine pancreas and liver

Answer 2

regulate blood borne energy substrate availability (post absorption) via hormones
glucose, fatty acids, ketone bodies and amino acids

Question 3

Where is the pancreas situated and what is its role

Answer 3

digestive pro-enzymes are secreted via pancreatic duct to second part of duodenum
It lies posteriorly to the peritoneum , close to major blood vessels, difficult to access
Lies in a C shaped curve of duodenum with a head, neck, body, tail and uncinate process

Question 4

what does the pancreatic duct combine with

Answer 4

common bile duct, and the three components of the sphincter of Oddi

Question 5

Tell me about pancreatic blood supply

Answer 5

mainly via the splenic artery (from coeliac trunk), as well as the pancreatico-duodenal arteries (from SMA or coeliac trunk)

Question 6

What are the primary functions of the exocrine pancreas

Answer 6

• neutralise acid

- deliver enzymes for macronutrient digestion in duodenum

Question 7

What are Acinar cells

Answer 7

-mains secretory cells
clusters are connected by intercalated ducts
-converge on collecting duct
-lining cells add ions and secretions

Question 8

Exocrine pancreas regulation of the cephalic phase

Answer 8

• Vagus nerve stimulates pancreatic secretions by releasing ACh and VIP
• 25% of pancreatic secretions

Question 9

Exocrine pancreas regulation of the Gastric phase

Answer 9

• Mediated by vasovagal reflexes

- 10% pancreatic secretions

Question 10

Exocrine pancreas regulation of the intestinal phase

Answer 10

controlled hormonally by secretin (in response to H+) and CCK (in response to fatty acids and monoacylglycerols)
65% pancreatic secretions

Question 11

What are the role of Zymogen granules in acing cells

Answer 11

• House inactive and active digestive enzymes
• secreted in response to CCK (and VIP, gastric releasing peptide)
• when activated they are exocytosed into luminal space

Question 12

How is the exocytosis regulated

Answer 12

hormonally and neurally

• CCK is released into interstitial space, enters blood stream, travels in circulation to pancreatic acing cells, binds with the CCKa receptors
• also binds to CCKa on vagal afferents giving efferent stimulation of pancreatic acinar cells via VIP

Question 13

how are ions secreted

Answer 13

Ion + serous fluid secretion occurs in both acing and intercalated duct cells

Question 14

How do acinar cells contribute to Ion secreting mechanisms

Answer 14

Basolateral CCK and ACh binding stimulates Cl- transport across apical membrane
Facilitates paracellular Na+ and water movement

Question 15

How to intercalated ductal cells contribute to ion secreting mechanisms

Answer 15

-Secretin and ACh bind in ductal cells
-activates cystic fibrosis transmembrane conductance regulators, Cl- channels, Cl-HCO3- transporters
Transporters recycle Cl- and HCO3-

Question 16

What happens when pancreatic secretion flow rate increases

Answer 16

HCO3- conc increases
Cl- conc decreases

HOWEVER
Na+ and K+ are not effected by flow rate
-Na+ is similar to plasma
-K+ slightly higher than plasma

Question 17

Where is the liver situated

Answer 17

lies across the upper abdomen, under the diaphragm, surrounded by the peritoneum (excluding base area

Question 18

What is the liver surrounded by

Answer 18

Glissons capsule

-thin connective tissue layer extensions into organ between lobules

Question 19

How is the liver supplied

Answer 19

hepatic portal vein (nutrients from the stomach and gut)

hepatic artery supplies hepatocytes with oxygen

Question 20

How is bile drained from the liver

Answer 20

canaculi that lie between the hepatocytes into bile ductules and eventually bile ducts

Question 21

Tell me about the livers lobes

Answer 21

• right and left lobes (separated by falciform ligament)
• a quadrate lobe next to gallbladder
• prosterior surface shows the caudate lobe next to the IVC

Question 22

What are the functions of the liver

Answer 22

• Synthesis and secretion of bile
• Storage of glucose, glycogen, proteins, vitamins and fats
• Detoxification of metabolic waste
• Synthesis of blood clotting and anticoagulant factors (fibrinogen and prothrombin)

Question 23

What are the constituents involved in the synthesis of bile

Answer 23

bile pigments (bilirubin), cholesterol, phospholipids, fatty acids, water and electrolytes)

Question 24

How are bile pigments derived

Answer 24

from the breakdown of haemoglobin
Kupffer cells (fixed phagocytes) play a role aswell

Question 25

What is responsible for the detergent and emulsifying effect off bile on fats

Answer 25

bile salts

Question 26

What is the role of hepatocytes

Answer 26

they secrete bile into canaliculi, aBILE cross series of bile ducts until form common hepatic duct
this bile flow is in the opposite direction of blood from hepatic artier and portal vein

Question 27

Where does bile go

Answer 27

from common bile duct into duedenum or gallbladder

Question 28

What is the role of the sphincter Oddi

Answer 28

controls path of bile:
contracted = bile mainly to gallbladder
relaxed = mainly to duodenum
(regulated by CCK)

Question 29

What is the role of Bile acids

Answer 29

Emulsify lipids

Question 30

How is bile concentrated

Answer 30

Na+ and Cl- are reabsorbed causing isosmotic water and reabsorption

Question 31

What is the role of the Gall bladder

Answer 31

Stores and distributed bile in concentrated form
contracts = expels
in response to CCK
if its by vagal stimulation there is a weak contraction

Question 32

What substances inhibit bile acid secretion

Answer 32

Somatostatin

Noradrenaline

Question 33

Non-biliary live functions

Answer 33

Metabolism: of CHO and proteins and fat
stores and releases glycogen
Detoxification:
-key removal of ammonia and ethanol and drug biotrasnforamtions
immune system function:
-removal of intestinal bacteria from portal blood so is none in systematic circulation