Choudhury - Pancreas

Question 1

Acinus (exocrine pancreas) (function)

Answer 1

secretory acini and ducts
constitute ~98% of pancreatic mass

acini
20-40 secretory cells coalesce into a sac-like unit
cells secrete digestive enzymes

Question 2

Acinar cell (exocrine pancreas) (function)

Answer 2

secrete digestive enzymes

packaged in zymogen granules,

released into acinar lumen   amylase, lipase, and trypsinogen

Question 3

Centroacinar cell (exocrine pancreas) (function)

Answer 3

secrete bicarbonate

Question 4

Lobule (exocrine pancreas) (function)

Question 5

Lobe (exocrine pancreas) (function)

Question 6

Pancreatic duct (exocrine pancreas) (function)

Question 7

Islet of Langerhans (endocrine pancreas) (function)

Answer 7

accounts for <2% of pancreatic mass

islands of cells - islets of Langerhans

Question 8

Alpha cell (endocrine pancreas) (function)

Answer 8

25-35% of islet cells
produce glucagon

Question 9

Beta cell (endocrine pancreas) (function)

Answer 9

55-65% of islet cells

produce insulin, amylin

Question 10

Delta cell (endocrine pancreas) (function)

Answer 10

5-15% of islet cells
produce somatostatin

Question 11

PP cell (endocrine pancreas) (function)

Answer 11

<2% of islet cells produce pancreatic polypeptide

(regulatory peptide)

stimulates gastric chief cells

inhibits bile secretion and intestinal motility

inhibits pancreatic enzymes and HC03- secretion

Question 12

Proteolytic endopeptidases (exocrine digestive enzyme)

Question 13

Lipases (exocrine digestive enzyme)

Question 14

Amyolytic endopeptidases (exocrine digestive enzyme)

Question 15

Nucleolytic enzymes (exocrine digestive enzyme)

Question 16

Insulin (function as an endocrine hormone)

Answer 16

released in response to glucose
promotes uptake of glucose into target tissues
(primarily liver, muscle and fat)

primary islet hormone

Question 17

Glucagon (function as an endocrine hormone)

Answer 17

secreted in response to low blood glucose
counter-regulatory hormone
promotes production of glucose from
liver glycogen
glucose precursors

“Important in starvation”

Question 18

Somatostatin (function as an endocrine hormone)

Answer 18

Somatostatin inhibits insulin and glucagon secretion (“inhibitory input”).

Question 19

Pancreatic polypeptide (PP) (function as an endocrine hormone)

Question 20

VIP (function as an endocrine hormone)

Answer 20

vasoactive intestinal peptide (VIP)

similar to action of glucagon (hyperglycemic & glycogenolytic)

also affects secretory activity & motility in gut

stimulates pancreatic exocrine secretion

Plays a role in vasodilation, arterial BP, heart contractility, glycogenolysis

Question 21

Secretin (function as an endocrine hormone)

Answer 21

acts locally

stimulates HC03- secretion (in pancreatic juice)

stimulates pancreatic enzyme secretion

Question 22

Motilin (function as an endocrine hormone)

Answer 22

increases gastric and intestinal motility

Question 23

Substance P (function as an endocrine hormone)

Answer 23

has neurotransmitter properties

Question 24

Ghrelin (function as an endocrine hormone)

Answer 24

stimulates appetite

Question 25

Describe and discuss the mechanisms of communication within the pancreas, between pancreatic cells and extra-pancreatic cells, including blood supply, paracrine relationships, junctional communications (gap junctions), innervation(sympathetics & parasympathetics), and the islet-acinar axis (islet acinar portal system).

Answer 25

blood supply paracrine relationships junctional communications (gap junctions) innervation: sympathetics & parasympathetics islet-acinar axis (islet acinar portal system)

Question 26

Location of pancreas

Answer 26

located in the retroperitoneal space attached to the duodenum and spleen at level of ~2nd lumbar vertebra oblique, transverse in position

Question 27

Pancreatic development

Answer 27

endodermal in origin develops from ventral & dorsal pancreatic buds

Question 28

Pancreatic head details

Answer 28

flattened structure, 2 – 3 cm thick includes uncinate process attached to 2nd and 3rd portions of duodenum ** gastroduodenal artery defines border with neck** yields superior pancreaticoduodenal artery (SPDA) divides into anterior & posterior SPDA branches to duodenum and rt. border of head

Question 29

Pancreatic neck details

Answer 29

2 to 3 cm in length antero-superior surface supports pylorus of stomach straddles SMV and PV superior mesenteric arterial branches emerge at inferior border posteriorly, SMV & splenic vein converge to form portal vein

Question 30

Body of the pancreas (don't memorize)

Answer 30

longest segment of organ structure anterior surface separated from stomach by lesser sac posterior surface related to: aorta, lt. adrenal, lt. renal vessels, and upper 1/3rd of lt. kidney splenic vein embedded in posterior surface inferior surface is covered by tranverse mesocolon

Question 31

Pancreatic tail

Answer 31

pancreatic tail short, narrow segment lies at level of 12th thoracic vertebra terminates at splenic hilum, within splenophrenic lig. anteriorly, related to splenic flexure of colon may be injured during splenectomy (fistula)

Question 32

Two pancreatic ducts ("be aware")

Answer 32

Main duct (duct of Wirsung) runs length of pancreas, merges with common bile duct at ampulla of Vater 2–4mm diameter, ~20 secondary branches ductal pressure is higher than in common bile duct to prevent backflow, damage Accessory duct (duct of Santorini) drains superior portion of head & empties separately into duodenum

Question 33

How many different arterial sources supply the pancreas? (list them, be familiar)

Answer 33

Seven... ## Footnote superior pancreaticoduodenal artery (from gastroduodenal artery) inferior pancreaticoduodenal artery (from sup. mesenteric artery) ant. & post. branches of each anastomose dorsal pancreatic artery (from splenic artery) great pancreatic artery (from splenic artery) caudal pancreatic artery (from splenic artery) + numerous other small, un-named branches supply body & tail

Question 34

Veins of the pancreas

Answer 34

venous drainage generally follows arterial supply ant. and post. arcades drain head & body drain to SMV and/or to portal vein splenic vein drains body & tail ultimately, all drain into hepatic portal vein Significance? Insulin drains to liver.

Question 35

"Final" digestive juice from pancreas details

Answer 35

alkaline fluid colorless, odorless, isosmotic 500-800ml secreted per day enzymes activated in duodenum by acidic environment pH neutralizes gastric acid & buffers intestinal pH

Question 36

Amylin is secreted with what other hormone?

Answer 36

Insulin

Question 37

How are islets arranged in the human pancreas?

Answer 37

precise relationship among cells types all cells “randomly” distributed, but arrayed along vessels - such that all cells see blood

Question 38

Islet-acinar axis

Answer 38

* islets of Langerhans within the exocrine pancreas has a specific purpose * insulin regulates both metabolism and secretion of pancreatic acinar * nutrients in the gastrointestinal tract will stimulate insulin secretion via nervous and hormonal pathways * insulin released will not only regulate blood glucose, but will also potentiate exocrine pancreatic secretion * insulin also stimulates other acinar cell functions, such as transport of amino acids or glucose, as well as protein and enzyme synthesis * insulin directly regulates the acinar pancreas * endogenous insulin potentiates zymogen release * insulin has both short-term and long-term effects on the exocrine pancreas * a suppressive role of the islet-acinar axis via endogenous somatostatin and/or pancreatic polypeptide is suggested

Question 39

Islet-acinar axis con...