GIT secretions

Question 1

3 phases of gastric secretion

Answer 1

• cephalic - reflex (secrete gastrin + histamine)
• gastric - stimulate receptors (secrete gastrin + histamine)
• intestinal - stimulate secretion (secrete secretin)

Question 2

exocrine secretion definition

Answer 2

secretion of substances onto an epithelial surface by way of a duct
ex: salivary, mucus

Question 3

endocrine secretion definition

Answer 3

substances secreted directly into blood by way of ductless glands
ex: pancreas, gonads

Question 4

modes of cellular secretion - merocrine definition

Answer 4

vesicles fuse with apical plasma membrane to release products into duct
ex: saliva

Question 5

modes of cellular secretion - apocrine definition

Answer 5

products released in vesicles into duct

Question 6

modes of cellular secretion - hollocrine definition

Answer 6

products accumulate in secretory cells - die - cell and products released into a short duct
ex: oils on skin

Question 7

what do stomach paretial cells secrete

Answer 7

HCL
intrinsic factor

Question 8

what to stomach cheif cells secrete

Answer 8

pepsinogen
gastric lipase

Question 9

what do stomach G cells secrete

Answer 9

gastrin

Question 10

gastrin function

Answer 10

promotes growth of gut mucosa

Question 11

What regulates SI secretion

Answer 11

chyme

Question 12

SI exocrine secretions

Answer 12

mucus, peptidase, sucrase, maltase, lactase, lipase, enterokinase

Question 13

SI endocrine secretions

Answer 13

secretin, cholecystokinin

Question 14

brunners glands function

Answer 14

secrete alkaline mucoid fluid (no enzyme)
protect SI mucosa from stomach acid damage

Question 15

where are biles acids produced

Answer 15

cholesterol in smooth ER of HEPATOCYTES

Question 16

composition of bile

Answer 16

water, salts, phospholipids, cholesterol, pigments

Question 17

Pancreas exocrine secretions

Answer 17

trypsiongen, carboxylpepetidase, aminopeptidase, lipase, amylase, nuclease

Question 18

what stimulates pancreas secretions

Answer 18

acetylcholine, cholecystokinin, secretin

Question 19

trypsinogen function

Answer 19

hydrolyze proteins into peptides and amino acids

Question 20

carboxypeptidase function

Answer 20

remove C terminal of amino acid

Question 21

aminopeptidase function

Answer 21

catalyze cleavage of amino acids from amino terminus of protein or peptide substrates

Question 22

lipase function

Answer 22

breakdown fats into fatty acids and glycerol

Question 23

amylase function

Answer 23

hydrolyzse glycocidic bonds in starch molecules converting carbs into simple sugars

Question 24

nuclease function

Answer 24

catalyse cleavage in phosphodiester bonds, breakdown DNA molecules

Question 25

what do acinar cells do

Answer 25

secrete digestive enzymes

Question 26

pancreatic hormones

Answer 26

insulin + glucagon

Question 27

enterocyte fucntion

Answer 27

absorptive unit in SI
energy supply - fatty acids + glucose

Question 28

mechanisms of absorption over brush border into cells

Answer 28

facilitated diffusion
active transport
passive fidducion
endocytosis

Question 29

protease function

Answer 29

breakdown proteins and peptides
hydrolyze peptide bonds

Question 30

what secretes proteases

Answer 30

zymogens

Question 31

two types of proteases and their function

Answer 31

• endopeptidase - attack and cleavage middle of amino acid chain
  ex: stomach and pancreas
• exopeptidase - split of amino acids from end of chain
  ex: pancreas and SI glands

Question 32

pepsins definition

Answer 32

gastric proteases
found in pepsinogen secreted by cheif cells
attacks all proteins

Question 33

chylomicrons function

Answer 33

vesicle like cells
transport triglycerides + cholesterol absorbed by intestinal epithelia

Question 34

micelles function

Answer 34

carry fat digestion products to brush border for absorption