Exam #5: Pancreas Flashcards Preview

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Flashcards in Exam #5: Pancreas Deck (22)
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1
Q

What are the three key cell types that are important to the exocrine function of the pancreas?

A

1) Acinar cells= protein synthesis
2) Duct cells= fluid & bicarbonate
3) Goblet cells mucin synthesis & secretion

2
Q

What are the acinar cells of the pancreas? What is the function of the acinar cells of the pancreas?

A

Acinar cells are the protein synthesizing cells that:

  • Secrete digestive enzymes
  • Secrete fluid
3
Q

What are duct cells & what do they produce?

A

Duct cells are cells lining the ducts of the pancreas that function in:

  • Bicarbonate secretion
  • Ion transport
  • Fluid transport

Generally, the duct cells have a product that is PROTECTIVE

4
Q

What are goblet cells & what do they produce?

A

Goblet cells produce mucin that:

  • lubricates
  • hydrates
  • protects
  • immune function
5
Q

What are the two primary stimuli for fluid and enzyme secretion by pancreatic acinar cells?

A
  • **CCK & ACh
  • CCK promotes fluid & enzyme secretion (which is enhanced by VIP or secretin)

*****Note that these two signals also promote the secretion of cholride, leading to Na+ & H20 accumulation in the lumen of the pancreatic ducts

6
Q

What are the zymogens produced by the pancreas? How are zymogens stored in the pancreas?

A
Trypsinogen* 
Chymotrypsin
Proelastease 
Proprotease E 
Procarboxypeptidase A 
Procarboxypeptidase B 

*****These are inactive proteases in the pancreas

7
Q

How are zymogens activated in the duodenum?

A
  • Secreted in an inactive form & travel from: 1) pancreatic duct, 2) common bile duct, 3) duodenum
  • In duodenum, trypsinogen is converted to trypsin via enterokinase that is secreted by duodenal cells; trypsin activates the other proteases
8
Q

What is the primary stimulus for the secretion of bicarbonate from the pancreatic duct cells?

A
  • ***Secretin action on pancreatic duct cells
    1) Low duodenal pH= secretin secretion
    2) Secretin mainly induces duct cell secretion of bicarbonate
9
Q

How does else does secretin regulate acid secretion?

A

1) Increased release of somatostatin from gastric D-cells
2) Decreased gastrin secretion from G-cells
3) Decrease proton pump expression by parietal cells

10
Q

What are the three phases of pancreatic secretion?

A

1) Cephalic
2) Gastric
3) Intestinal

11
Q

What happens in the Cephalic phase of pancreatic secretion?

A

Vagal pathways induce pancreatic enzyme secretion in response to site, taste, smell, & mastication

12
Q

What happens in the Gastric phase of pancreatic secretion?

A

Vagal/ Gastrin induce pancreatic enzyme secretion in response to distention, gastrin, and peptides in the stomach

13
Q

What happens in the Intestinal phase of pancreatic secretion?

A

CCK, Secretin, & Enterpancreatic reflexes lead to pancreatic enzymes secretion in response to amino acids, fats, and H+ in the small intestine

*****Note that this is the phase the results in the majority of maximum enzyme secretion

14
Q

What is the stimulus for returning the levels of pancreatic secretion from the fed state to the interdigestive state?

A

Once the contents of the intestines reach the ILEUM, fats in the ileum induce the release of Peptide YY & Somatostatin; these hormones return pancreatic secretions to interdigestive levels

15
Q

What are the regulators of the cyclic pattern seen in the MMC?

A

1) Stimulation of the PNS pathways
2) CCK
3) Inihibition by a a-adrenergic input

16
Q

What cell type secretes CCK? What is the key stimulus for this cell to release CCK?

A
  • I-cell

- Lipids

17
Q

Aside from the zymogens, what are the other pancreatic enzymes that are secreted?

A

Active enzymes are secreted from the pancreas in addition to the inactive proteases:

  • a-amylase
  • Carboxyle ester lipase
  • RNase
  • DNase
  • Colipase
  • Trypsin inhibitor
18
Q

What is pancreatitis?

A

Inflammation of the pancreas

19
Q

What is acute pancreatitis?

A

Acute inflammation of the pancreas associated typically with alcoholism or obstruction of the pancreatic or common bile duct leading to:

  • Autodigestion of pancreas
  • Inflammatory mediators released
  • Damage to other tissues
  • Malabsorption of dietary nutrients
20
Q

What is chronic pacreatitis?

A

Continued damage of the pancreas, typically from alcohol abuse

21
Q

What can pancreatitis lead to?

A
  • Malabsorption Syndrome

- Cancer i.e. adenocarcinoma of the pancreas

22
Q

Overview the anatomy of the pancreas i.e. how do pancreatic enzymes get into the duodenum?

A

1) Pancreatic enzymes released from acinar cells into pancreatic duct
2) Pancreatic duct–>common bile duct
3) Common bile duct–>duodenum via “Sphincter of Oddi “

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