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Flashcards in Exocrine Pancreas Deck (51)
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1

The pancreas is _____

Bi-lobed
- body: pylorus
- right lobe: mesoduodenum, ventral to right kidney, apposition to duodenum
- left lobe: caudal to stomach and liver

2

Exocrine functions of pancreas

- enzymes secreted into a duct
- ducts lead to external environment
- digestive enzymes

3

Endocrine functions of pancreas

- hormones secreted into the blood
- function at distant sites, not on the cells that secreted them
- insulin

4

Exocrine histologic anatomy

- acini: digestive enzymes
- ducts: bicarbonate

5

Endocrine histologic anatomy

Islets of Langerhans
- alpha cells: glucagon
- beta cells: insulin
- delta cells: somatostatin/gastrin
- PP cell: pancreatic polypeptide

6

Acini are arranged as a ______

Cluster of grapes
- lead out to the pancreatic or accessory duct
- bicarb is made within the ducts

7

Sympathetic innervation

Inhibitory!!!
- celiac plexus
- mesenteric plexus

8

Parasympathetic innervation

Stimulatory!!
- branches of vagus or other cholinergic nerves in the enteric nervous system
- terminate in acini (exocrine) or islets (endocrine)

9

In dogs, the bile duct enters _______

Major duodenal papilla

10

Accessory pancreatic duct (dogs)

Most important
- enters minor duodenal papilla
- separate from bile duct

11

Pancreatic duct (dogs)

Less important
- may not be present
- empties into major duodenal papilla separate from bile duct

12

Most pancreatic secretions in the dog go into the _______

Accessory pancreatic duct

13

Pancreatic duct (cats)

Most important
- enters major duodenal papilla --> after joining with the common bile duct first

14

Accessory pancreatic duct (cats)

Only present in 20% of cats

15

Triaditis

Common in cats
- inflammation affects the liver, common bile duct, and the gallbladder = back up of bile flow
- pancreatitis can make cats yellow, liver complications are secondary

16

What are the 3 functions of the exocrine pancreas?

- release of mostly inactive digestive enzymes
- neutralization of gastric acid
- secretion of intrinsic factor

17

Intrinsic factor

Secreted by parietal cells in humans
- facilitates B12 absorption in the distal small intestine

18

Lack of B12

Pernicious anemia in people
- diarrhea in dogs and cats

19

Bicarbonate secretion

Released by ductal cells
- neutralizes gastric acid
- intestinal mucosa protection
- increased pH necessary for enzyme activity
- reaches 5 times the plasma bicarb concentration

20

Enzymes are only functional at a _______

Higher pH

21

What are the 3 functions of pancreatic enzymes?

- protein digestion
- carbohydrate digestion
- fat digestion

22

Protein digestion

Zymogens
- trypsinogen
- chymotrypsinogen
- procarboxypeptidase

23

Carbohydrate digestion

Pancreatic amylase

24

Fat digestion

- pancreatic amylase
- cholesterol esterase
- phospholipase

25

Proteolytic enzymes following activation

- trypsin
- chymotrypsin: both split whole proteins or partially-digested peptides into smaller peptides
- carboxypeptidase: splits some peptides into individual amino acids

26

Pancreatic amylase

Hydrolyzes starches
- glycogen and others
- into di- or trisaccharides

27

Pancreatic lipase

Neutral fat --> FA + monoglycerides
- cholesterol esterase: hydrolysis of cholesterol esters
- phospholipase: separates FAs from phospholipids

28

Protection from auto-digestion

- zymogen synthesis (proteases)
- segregation into vacuoles in acinar cell (separate from lysosomes)
- trypsin inhibitors in cytoplasm (and some are circulating)
- sphincter at pancreatic duct (inhibits reflux)

29

Zymogen

Prozymes (inactive enzyme)
- trypsinogen
- chymotrypsinogen
- activation required

30

Zymogens are synthesized by _______

Ribosomes
- formation and storage in vesicles