Pancreatic & Biliary Secretions Flashcards Preview

Human Epithelial Biology > Pancreatic & Biliary Secretions > Flashcards

Flashcards in Pancreatic & Biliary Secretions Deck (49)
1

What are the three parts of the small intestine?

Duodenum
Jejunum
Ileum

2

What does the small intestine receive?

chyme
pancreatic juice
bile

3

What structures make the small intestine ideal for absorption?

circular folds
villi
microvilli

4

What does the duodenum secrete into the blood?

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

5

How much does the duodenum secrete a day?

2L

6

What are the enhancing control mechanisms for secretion?

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

7

What is the inhibitory control mechanism for secretion?

sympathetic nerve activity

8

What does the secretions from the small intestine contain?

mucus
aqueous salt
no digestive enzymes

9

What transporters are involved in secretion?

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

10

What happens during segmentation?

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

11

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

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

12

What is the gastroileal reflex?

where segmentation occurs in the empty ileum due to gastrin

13

What peristalic activities occur in the fasting state?

a few localised contractions
the migrating motor complex

14

What is the migrating motor complex?

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

15

What triggers the migrating motor complex?

motilin

16

what inhibits the migrating motor complex?

feeding and vagal activity
gastrin and CCK

17

Where do the digestive enzymes from the pancreas come from?

acinar cells

18

What does the pancreas secrete for digestion?

aqeous NaHCO3 from duct cells
digestive enzymes from the acinar cells

19

What pancreatic enzymes are produced by the acinar cells?

trypsinogen
chymotrypsinogen
procarboxypeptidase
pancreatic amylase
pancreatic lipase

20

What activates trypsinogen in the first instance?

enterkinase

21

where is enterokinase made?

the mucosal cells

22

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

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

23

What are the three phases of pancreatic secretion?

cephalic
gastric
intestinal

24

What occurs in the cephalic phase of pancreatic secretion?

increase vagal stimulation of acinar cells

25

What occurs in the gastric phase of pancreatic secretion?

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

26

What occurs in the intestinal phase of pancreatic secretion?

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

27

What are the hepatic ducts?

left, right, common

28

What are the bile ducts?

cystic, common

29

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

sphincter of oddi

30

how much bile is produced daily?

0.6-1.2L

31

Where is bile stored between meals?

in the gall bladder

32

What happens to bile during a meal?

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

33

What causes the sphincter of Oddi to open ?

CCK

34

What two cells secrete bile?

hepatocytes
cholangiocytes

35

What does bile specifically aid in the digestion of?

fats

36

what increases the flow rate of bile?

secretin

37

what does the bile contribute to?

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

38

what is hepatic bile composed of?

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

39

What are bile salts usually conjugated with?

glycine or taurine - occasionally sulfate

40

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

it is recycled enterohepatically from the gut

41

What resins bind bile salts to lower cholesterol?

colestryamine
colestipol

42

How is bile synthesis regulated?

dependent on hepatic blood concentration of salts
low stimulates production

43

How is bile secretion regulated?

Bile salt returning to liver stimulates secretion
CCK
Secretin
Vagal Activity

44

What is secretin released in response to?

acid in the lumen of the gut

45

What does secretin stimulate?

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

46

What is CCK released in response to?

fat and protein in the duodenal lumen

47

What does CCK stimulate?

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

48

What drugs might you use in analgesia for GI?

morphine, bupenorphine, pethidine

49

What drugs might you use to ease biliary spasm?

atropine, GTN