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Flashcards in Physiology of the pancreas Deck (20):
1

Which arteries supply the pancreas?

celiac and SMA

2

What percent of the pancreas makes up the exocrine/endocrine portions?

80% exocrine
2% endocrine

3

The ventral pancreatic bud in embryology becomes:

The uncinate process. The dorsal bud=body, tail, and head

4

What forms the pancreatic duct?

The ventral duct anastamoses with the dorsal duct. When these systems fail to fuse, it is called pancreas divisum

5

What are the components of the langerhans cells and what do each of these secrete?

A cells: glucagon
PP cells: Pancreatic polypeptide
D cells: Somatostatin

6

Acinar cells have receptors for which hormones/neurotransmitters?

CCK (hormone)
Gastrin-releasing peptide
Acetylcholine
VIP.
-->All of these stimulate pancreatic digestive enzymes

7

How does the hormone CCK stimulate pancreatic secretion?

Primarily through a vagal afferent/efferent pathway.
The vagal efferents release GRP, Ach, and VIP

8

What hormone is the primary stimulant of ductal cell secretion?

Secretin. It works by increasing cAMP, which inactivates the Cl channel, causing increased secrecretory flow, high [Cl], turning on the Cl/HCO3 antiport system and thus alkalinization of pancreatic juices

9

What stimulates secretin release?

Acidity of stomach contents

10

What potentiates secretin's effects?

Acetylcholine.

11

How does the cephalic phase mediate its effects? List the stimulus, mediator, and response.

STIMULUS - sight and smell of food
MEDIATOR - vagus efferents enteric nervous system GRP, Ach, VIP
PRIMARY RESPONSE - enzyme secretion

12

How does the gastric mediate its effects? List the stimulus, mediator, and response

STIMULUS - gastric distention
MEDIATOR - vagus efferents enteric nervous system GRP, Ach, VIP
RESPONSE - enzyme secretion

13

How does the intestinatl phase mediate its effects (there are two)

STIMULUS - fatty acids, amino acids in the duodenum
MEDIATOR – CCK vagus enteric nervous system --> GRP, Ach, VIP
Also direct CCK stimulation thru receptor on Acinar cell
RESPONSE - enzyme secretion

STIMULUS - H+ in duodenum
MEDIATOR - Secretin
RESPONSE - Bicarbonate and water secretion

14

What happens when the pancreas is stimulated by secretin?

Bicarb concentration increases and Cl concentration decreases

15

Most of the digestive enzymes of the pancreas digest what substance?

They're proteolytic

16

What are the important proteolytic enzymes from the pancreas?

Trypsinogen, chymotrypsinogen, proelastase, procarboxypeptidase, and prophospholipase A2

17

How are these proenzymes converted into enzymes?

Enterokinase converts trypsinogen to trypsin in the duodenum. Then trypsin converts more trypsinogen and other proenzymes to their active forms.

18

Aside from sequestration of enterokinase in the duodenum, what other mechanisms prevent pancreatic autodigestion?

1. Membrane enclosed compartments
2. Trypsin inhibitor in the acinar cell prevents the small amount of activated trypsin from harming the pancreas
3. Acidic pH in zymogen granules inactivates trypsin
4. Tight ductal epithelium

19

What are the three lipases secreted by the pancreas?

Lipase
PhospholipaseA2
Carboxylesterase

20

What else do you need for the full activity of pancreatic lipase

bile acids and colipase