functions and secretions of the pancreas

Question 1

pancreas

Answer 1

soft retroperitoneal gland
sits behind stomach
12-15cm x 2.5cm
has head, body, tail
releases 1.5L juices a day - into duodenum

pancreatic duct carries secretions to ampulla of vater
bile from gall bladder enters there too
bile produced by liver + contains bile salts

Question 2

where is the duodenum

Answer 2

at the start of the small intestine

Question 3

at the start of the small intestine

Answer 3

opening in the duodenum

Question 3

why are bile salts important

Answer 3

essential for fat absorption

Question 4

what type of gland is the pancreas

Answer 4

endocrine + exocrine

Question 5

function of the pancreas

Answer 5

exocrine + endocrine gland

Question 6

function of pancreas - exocrine gland

Answer 6

produces pancreatic juice

99% of cell mass

acinar + duct cells
juices released into duodenum
breaks down all categories of foodstuff

Question 7

function of pancreas - endocrine gland

Answer 7

produces hormones

1% of cell mass
islets of langerhans
hormones released into bloodstream
insulin, glucagon, somatostatin

Question 8

what are the exocrine secretions of pancreas

Answer 8

digestive enzymes
alkaline juice

Question 9

explain digestive enzymes - exocrine secretions

Answer 9

digests all food types

proteases
lipases
carbs
nucleases

Question 10

what type of foods do digestive enzymes digest

Answer 10

proteases
lipases
carbs
nucleases

Question 11

what do exocrine glands produce

Answer 11

pancreatic juice

Question 12

what do endocrine glands produce

Answer 12

hormones

Question 13

what are acinar cells specialised for

Answer 13

production + export of large quantities of digestive enzymes

Question 14

what are acinar cells stimulated by + release as a result

Answer 14

primarily by CHOLECYSTOKININ (CCK) to release enzymes

Question 15

what do acinar cells cause the gall bladder to do

Answer 15

contract + release bile

Question 16

what does CCK inhibit

Answer 16

HCl secretion from the stomach

Question 17

acinar cells surround ……. ….. …….

Answer 17

islet of langerhans

Question 18

acinar cells - full explanation

Answer 18

• specialised for production and export of large quantities of digestive enzymes
• stimulated primarily by CHOLECYSTOKININ (CCK) to release enzymes
• causes the gallbladder to contract and release bile
• CCK also inhibits HCl secretion from the stomach
• secretin and ACh can also induce acinar cell enzyme release

Question 19

what are duct cells specialised for

Answer 19

electrolytes

Question 20

when is HCO3- released fro the pnacreas

Answer 20

after eating

Question 21

duct cells - full explanation

Answer 21

• specialised for transport of electrolytes
• a HCO3- rich juice is released from the pancreas after eating but a Cl- rich juice is secreted when flow rates are low
• stimulated by secretin to release a HCO3- rich juice
• secretin also inhibits HCl secretion from the stomach
• ACh can also induce duct cell HCO3- release

Question 21

classes of enzymes in pancreatic juice

Answer 21

• proteases = 90%
• amylase = 7%
• lipases = 2%
• nucleases = <1%
• composition of juice is predominantly proteases

Question 22

what are the 3 phases of acid secretion

Answer 22

cephalic
gastric
intestinal

Question 23

what is the ampulla of vater

Answer 23

muscular structure surrounding bile and pancreatic ducts as they enter the duodenal wall

Question 24

what are the 2 type of exocrine secretions of the pancreas

Answer 24

digestive enzymes + alkaline juice

Question 25

digestive enzymes - digestion explanation

Answer 25

digests all food types proteases, lipases, carbs, nucleases

Question 26

alkaline juice - digestion explanation

Answer 26

numerous functions neutralises gastric acid prevents ulcer formation enables pancreatic enzymes to work enables micelle formation

Question 27

when is the plasma alkaline tide generated

Answer 27

when gastric parietal cells produced acid/H+ neutralised by pancreatic duct cells as they produce HCO3-

Question 28

describe the alkaline tide

Answer 28

1. stomach parietal cells send H+ (acid) into stomach and HCO3- into plasma 2. HCO3- in plasma causes alkaline tide - plasma pH INCREASES 3. when gastric acid arrives at duodenum, sensitive cells release secretin - signals pancreas to send HCO3- into duodenum + H+ into plasma 4. pancreatic HCO3- entering duodenum neutralises acid/H+ arriving from stomach 5. pancreatic H+ entering plasma neutralises alkaline tide/HCO3- arriving from stomach

Question 29

gastrin

Answer 29

secreted by: G-cells of stomach targets: gastric parietal + histamine secreting cells releasing stimuli: gastric distention + small peptides in stomach actions: stimulates gastric HCl secretion

Question 30

secretin

Answer 30

secreted by: endocrine cells of small intestine targets: stomach + pancreas releasing stimuli: acid in duodenum actions: inhibits gastric HCl secretion stimulates pancreatic HCO3- secretion

Question 31

CCK

Answer 31

secreted by: endocrine cells of small intestine - duodenum targets: stomach - esp. muscle pancreas gallbladder releasing stimuli: fat in duodenum actions: inhibits gastric emptying - DECREASE MOTILITY stimulated pancreatic enzyme secretion induces gallbladder contraction

Question 32

enzymes are secreted from the pancreas as ..... ....

Answer 32

inactive zymogens only become activated when in the SI

Question 33

why do enzymes only become activated when in the SI

Answer 33

to prevent autodigestion

Question 34

when pancreatic trypsinogen enters the SI what is it converted itno

Answer 34

the active digestive protease trypsin by ENTEROKINASE

Question 35

where is enterokinase found

Answer 35

in the brush border cells of the villi - so activation only takes place in the SI

Question 36

pancreatic enzymes

Answer 36

digestive enzymes secreted from the pancreas - inactive zymogens only activated in the SI prevents autodigestion of pancreas when pancreatic trypsinogen - enters the SI converted into active digestive proteases by enterokinase - found in the brush border cells of the villi activation only takes place in the SI trypsin can activate other inactive zymogens oancreas has trypsin inhibitors - prevent autodigestion

Question 37

how is trypsinogen converted into trypsin

Answer 37

enterokinase trypsin

Question 38

how is procarboxypeptidase converted into carboxypeptidases

Answer 38

trypsin

Question 39

how is chymotrypsinogen converted nto chymotrypsin

Answer 39

trypsin

Question 40

how is pro-elastase converted into elastase

Answer 40

trypsin

Question 41

how is prophospholipase A converted into phospholipase A

Answer 41

trypsin