Pancreatic & Biliary Secretions

Question 1

What are the three parts of the small intestine?

Answer 1

Duodenum
Jejunum
Ileum

Question 2

What does the small intestine receive?

Answer 2

chyme
pancreatic juice
bile

Question 3

What structures make the small intestine ideal for absorption?

Answer 3

circular folds
villi
microvilli

Question 4

What does the duodenum secrete into the blood?

Answer 4

Gastrin - D cells
CCK - I cells - duodenum and jejunum
Secretin - S cells - duodenum
Motilin - M cells - duodenum and jejunum
Glucose-dependent Insulinotropic peptide - K cells of duodenum and jujenum

Question 5

How much does the duodenum secrete a day?

Answer 5

2L

Question 6

What are the enhancing control mechanisms for secretion?

Answer 6

distension, irritation, gastrin and CCK, secretin and parasympathetic activity

Question 7

What is the inhibitory control mechanism for secretion?

Answer 7

sympathetic nerve activity

Question 8

What does the secretions from the small intestine contain?

Answer 8

mucus
aqueous salt
no digestive enzymes

Question 9

What transporters are involved in secretion?

Answer 9

Na-K ATPase - apical, NKCC - apical, CFTR - basolateral

Question 10

What happens during segmentation?

Answer 10

chopping movements move chyme back and forth vigorously with alternating contractions and relaxations of segments of the circular muscle

Question 11

What is the frequency of segmentation in the sm. intestine?

Answer 11

duodenum has 12/min, ileum has 9/min which moved food along

Question 12

What is the gastroileal reflex?

Answer 12

where segmentation occurs in the empty ileum due to gastrin

Question 13

What peristalic activities occur in the fasting state?

Answer 13

a few localised contractions

the migrating motor complex

Question 14

What is the migrating motor complex?

Answer 14

occurs between meals 90-120mins
strong peristalic contractions passing length of small intestine
clears sm. intestine of undigested debris, mucus and sloughed epithelial cells

Question 15

What triggers the migrating motor complex?

Answer 15

motilin

Question 16

what inhibits the migrating motor complex?

Answer 16

feeding and vagal activity

gastrin and CCK

Question 17

Where do the digestive enzymes from the pancreas come from?

Answer 17

acinar cells

Question 18

What does the pancreas secrete for digestion?

Answer 18

aqeous NaHCO3 from duct cells

digestive enzymes from the acinar cells

Question 19

What pancreatic enzymes are produced by the acinar cells?

Answer 19

trypsinogen
chymotrypsinogen
procarboxypeptidase
pancreatic amylase
pancreatic lipase

Question 20

What activates trypsinogen in the first instance?

Answer 20

enterkinase

Question 21

where is enterokinase made?

Answer 21

the mucosal cells

Question 22

What is the function of the aqeuos NaHCO3 secretion from the duct cells?

Answer 22

neutralises acid chyme
ideal pH for enzymes
protects mucosa from erosion by acid
CF patients have reduced secretion

Question 23

What are the three phases of pancreatic secretion?

Answer 23

cephalic
gastric
intestinal

Question 24

What occurs in the cephalic phase of pancreatic secretion?

Answer 24

increase vagal stimulation of acinar cells

Question 25

What occurs in the gastric phase of pancreatic secretion?

Answer 25

distension -> vagovagal reflex resulting in parasympathetic stimulation of acinar and duct cells

Question 26

What occurs in the intestinal phase of pancreatic secretion?

Answer 26

increased acid -> increased secretin -> increases NaHC03 from duct cells increased fat/protein in duodenum -> increased CCK -> increases enzymes from acinar cells

Question 27

What are the hepatic ducts?

Answer 27

left, right, common

Question 28

What are the bile ducts?

Answer 28

cystic, common

Question 29

Where do the secretions from the gall bladder, liver and pancrease all meet?

Answer 29

sphincter of oddi

Question 30

how much bile is produced daily?

Answer 30

0.6-1.2L

Question 31

Where is bile stored between meals?

Answer 31

in the gall bladder

Question 32

What happens to bile during a meal?

Answer 32

chyme in the duodenum stimulates gall bladder sm. muscle to contract via CCK and vagal impulses

Question 33

What causes the sphincter of Oddi to open ?

Answer 33

CCK

Question 34

What two cells secrete bile?

Answer 34

hepatocytes | cholangiocytes

Question 35

What does bile specifically aid in the digestion of?

Answer 35

fats

Question 36

what increases the flow rate of bile?

Answer 36

secretin

Question 37

what does the bile contribute to?

Answer 37

micelle formation neutralisation of chyme pH adjustment for enzymes protection of the mucosa

Question 38

what is hepatic bile composed of?

Answer 38

``` primary bile acids forming bile salts with Na and K cholic acid chenodeoxycholic acid water and electrolytes cholesterol lipids and phospholipids IgA Bilirubin ```

Question 39

What are bile salts usually conjugated with?

Answer 39

glycine or taurine - occasionally sulfate

Question 40

Why is only a small amount of bile produced in relation to the amount released?

Answer 40

it is recycled enterohepatically from the gut

Question 41

What resins bind bile salts to lower cholesterol?

Answer 41

colestryamine | colestipol

Question 42

How is bile synthesis regulated?

Answer 42

dependent on hepatic blood concentration of salts | low stimulates production

Question 43

How is bile secretion regulated?

Answer 43

Bile salt returning to liver stimulates secretion CCK Secretin Vagal Activity

Question 44

What is secretin released in response to?

Answer 44

acid in the lumen of the gut

Question 45

What does secretin stimulate?

Answer 45

Increased NaHCO3 secretion from pancreatic duct cells and hepatobiliary cells decreased gastric secretion and emptying

Question 46

What is CCK released in response to?

Answer 46

fat and protein in the duodenal lumen

Question 47

What does CCK stimulate?

Answer 47

increased digestive enzymes from acinar cells contracts gallbladder and relaxes sphincter of oddi decreased gastric secretion and emptying

Question 48

What drugs might you use in analgesia for GI?

Answer 48

morphine, bupenorphine, pethidine

Question 49

What drugs might you use to ease biliary spasm?

Answer 49

atropine, GTN