Pancreatic and Biliary Digestion and Disease Flashcards Preview

Digestive physiology and pathology > Pancreatic and Biliary Digestion and Disease > Flashcards

Flashcards in Pancreatic and Biliary Digestion and Disease Deck (15)
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1
Q

What are the three enteroendocrine cells in the duodenum and what do they secrete?

A

I cells- cholecystokinin, sense fats and proteins
S cells- Secretin, sense low pH (acidic env.)
Enterochromaffin cells- serotonin, sense irritants and serotonin will promote gut motility

2
Q

How are pancreatic enzymes activated? (proteases)

A

trypsinogen is converted to trypsin by enteropeptidase on cell surfaces,
Chymotrypsinogen is converted to chymotrypsin by trypsin.
Trypsin can also cleave trypsinogen

3
Q

What two ways does CCK stimulate pancreatic enzyme release?

A
  • Secreted into blood stream to pancreas where it affects acinar cells
  • secreted into afferent fibres next to I cells, to vagus nerve in brainstem thus stimulating pancreatic activity via vagus nerve
4
Q

Why must the duodenum be of neutral pH?

A

inactivate pepsin; optimum pH for enzymes; increase FA solubility; prevent mucosal damage

5
Q

How is bicarbonate secreted?

A
  • bicarbonate absorbed into cell (basolaterally) with Na+
  • also water and CO2 turned into bicarbonate by carbonic anhydrase
  • secretion involves CFTR transporter and HCO3- and Cl- antiport
6
Q

How does secretin control bicarbonate secretion?

A

enters blood, binds to ductal cells, increase cAMP, increase CFTR activity, more alkaline secretion

7
Q

What else does CCK do?

A

Causes bile production in liver, gallbladder contraction and relaxation of sphincter of Oddi

8
Q

What is cystic fibrosis and how does it affect the pancreas?

A

autosomal recessive disease that is a mutation of te CFTR gene, can cause pancreatic insufficiency
a defective CFTR channel means no bicarbonate secreted, etc
-cells accumulate Cl-, draws Na+ and water out
-result is viscous, mucous secretion, causings blockages and increased likelihood of infection. Also build up of enzymes can cause autodigestion

9
Q

What molecules are in bile?

A

bilirubin; bile salts; cholesterol; phospholipids

10
Q

Where is bile reabsorbed?

A

terminal ileum

11
Q

What is the function of bile?

A

Absorption of vitamins A, D, E and K by bile acids

removal of bilirubin in faeces

12
Q

What two ways are bile flow driven?

A

Acid dependent- movement of bile into caniliculi actively causes water to follow
Acid independent- transport of other solutes and electrolytes
Reabsorption and secretion by ducts

13
Q

What is cholestasis and what will it cause?

A

obstruction to bile flow, can cause increased liver and biliary tract pressure, causing tight junctions to break, causing contents to leak into circulation (jaundice)

14
Q

What are gall stones?

A

a.k.a Cholelithiasis, primarily concentrates of cholesterol or bilirubin and bile salts, can cause biliary obstruction

15
Q

What else can cause cholestasis, and what are the effects of prolonged cholestasis?

A

Cholangiocarcinoma or pancreatic cancer of head.
Jaundice; itchiness; nausea; malabsorption of fat.

potential palpable iliac fossa lymph node (Virchows)