GIT physiology 3

Question 1

carbohydrates are digested by

Answer 1

name-ases

Question 2

proteins are digested by

Answer 2

proteases/peptidases

Question 3

fats are digested by

Answer 3

lipases

Question 4

epithelial cells lining the pancreatic ducts

Answer 4

duct cells

Question 5

duct cells secrete

Answer 5

HCO3-, Na+, K+ and water

Question 6

enzymes are secreted by

Answer 6

acinar cells

Question 7

pancreatic secretions pH

Answer 7

alkaline

about pH 8

Question 8

functions of the pancreatic secretions

Answer 8

digestion of lipids, proteins and carbohydrates
neutralising pH of acid chyme entering the duodenum
create suitable pH for pancreatic digestive enzymes

Question 9

major pancreatic enzymes

Answer 9

trypsin 
chymotrypsin 
carboxypeptidases
elastases
nucleases
pancreatic amylase
pancreatic lipase
cholesterol esterase
phospholipase

Question 10

why is the pancreas not digested

Answer 10

proteases are synthesised in an inactive form

Question 11

trypsinogen

Answer 11

inactive form of trypsin

Question 12

trypsinogen is activated by

Answer 12

enterokinase

Question 13

tryspin

Answer 13

activates others eg. chymotrypsinogen, procarboxypeptidase

Question 14

acute pancreatitis

Answer 14

pancreas may digest itself within hours

Question 15

synthesis and exocytosis of enzymes are controlled by

Answer 15

CCK and ACh

Question 16

inactive proteases are synthesised and stores as

Answer 16

zymogen granules

Question 17

regulation of pancreatic secretion

Answer 17

• acetyl choline
• secretin
• cholecystokinin
• somatostatin

Question 18

cephalic phase

Answer 18

acetyl choline from vagus nerve

does not result in any secretion into the duodenum, just starts production

Question 19

secretin and cholecystokinin

Answer 19

produced by chemically sensitive cells in the duodenum

not initiated until gastric emptying

Question 20

cholecystokinin produced by

Answer 20

gut mucosal “I” cells

Question 21

secretin released in response to

Answer 21

acid in the duodenum

Question 22

secretin acts on

Answer 22

duct cells - produce bicarbonate

Question 23

secretin is produced by

Answer 23

duodenal “S” cells

Question 24

somatostatin produced by

Answer 24

intestinal “D” cells

Question 25

cholecystokinin secreted in response to

Answer 25

duodenal fat and protein

Question 26

cholecystokinin acts on

Answer 26

enzyme production/secretion by acinar cells | opens duodenal papilla - CCK receptors on the smooth muscle on the sphincter of oddi

Question 27

sphincter of oddi

Answer 27

allows pancreatic juices and bile to enter

Question 28

somatostatin acts on

Answer 28

is inhibitory

Question 29

3 phases of pancreatic secretiion

Answer 29

1. cephalic phase 2. gastric phase 3. intestinal phase

Question 30

cephalic phase controlled by

Answer 30

vagus nerve

Question 31

gastric phase

Answer 31

gastrin binds CCK-receptos

Question 32

intestinal phase

Answer 32

CCK, secretin and ACh released

Question 33

S cells produce

Answer 33

secretin

Question 34

stimulus to secrete secretin

Answer 34

H+ ion contact with mucosal S calls | also protein catabolites

Question 35

half life of secretin

Answer 35

short - 5 mins

Question 36

main action of secretin

Answer 36

stimulates HCO3- secretion by pancreas duct cells neuropeptide decreases gastric H+ secretion causes pyloric sphincter contraction

Question 37

I cells secrete

Answer 37

CCK

Question 38

stimulus for CCK secretion

Answer 38

long chain fatty acids, peptides, AAs, (generally protein digestion products

Question 39

CCK is inhibited by

Answer 39

trypsin in lumen and somatostatin from D cells in the small intestine

Question 40

main action of CCK

Answer 40

stimulates pancreatic acinar cell enzyme production and secretin relaxation of the sphincter of odd neuropeptide inhibits gastric emptying, stimulates enetrokinase synthesis, enhances intestinal motility, glucagon release

Question 41

bile stored in

Answer 41

gall bladder

Question 42

bile discharged into

Answer 42

duodenum

Question 43

role of bile

Answer 43

emulsifies fats to increase access to lipases

Question 44

bile acids synthesised from

Answer 44

cholesterol

Question 45

bile acids synthesised by

Answer 45

hepatocytes

Question 46

bile acids conjugated with

Answer 46

glycine or taurine ionises the bile acids prevents immediate reabsorption

Question 47

2 degree bile acids converted by

Answer 47

converted by bacteria removes glycine/taurine enables reabsorption

Question 48

why are bile acids conjugated

Answer 48

to prevent immidiate reabsorption

Question 49

conversion to 2 degree bile acids enables

Answer 49

reabsorption

Question 50

bile acids cycle between

Answer 50

the liver and the small intestine

Question 51

total bile acid pool

Answer 51

about 3g

Question 52

percentage bile acids lost daily

Answer 52

5-10%

Question 53

the biliary system

Answer 53

produces bile remove excess cholesterol remove bilirubin by modifying it

Question 54

things lost by diffusion in the biliary system

Answer 54

- water - glucose - calcium - glutathione - amino acids - urea

Question 55

causes of gallstone

Answer 55

too much absorption of water from bile too much absorption of bile acids from bile too much cholesterol in bile immflamuation of epithelium

Question 56

bile is release in response to

Answer 56

CCK

Question 57

pancreatic secretion is regulated by

Answer 57

ACh, secretin, and CCK