pancreatic and intestinal secretions

Question 1

what are the exocrine secretions of the pancreas

Answer 1

bicarbonate ions

lipase, amylase and protease

Question 2

what factors increase the secretion of bicarbonate

Answer 2

secretin

cholecystokinin

Question 3

what increases secretion of digestive enzymes from the pancreas

Answer 3

parasympathetic NS via the vagus

inhibited by sympathetic

Question 4

what are pancreatic enzymes stored in until they are ready for release

Answer 4

condensed zymogen granules

Question 5

what cells release the aqueous component of secretion

Answer 5

centroacinar cells and ductal cells

Question 6

what does the pancreatic fluid contain

Answer 6

potassium, sodium, chloride and bicarbonate ions

it is isotonic

Question 7

what cells release digestive enzymes

Answer 7

acinar cells

Question 8

in what form are pancreatic proteases secreted

Answer 8

inactive form

activated in the duodenum by enterokinase

Question 9

what are the phases of pancreatic secretion

Answer 9

cephalic, vagus mediated
gastric, vagus mediated
intestinal phase- 80%

Question 10

what substance do duodenal 1 cells release in response to small peptides, fatty acids and amino acids

Answer 10

CCK (cholecystokinin)

Question 11

what neurotransmitter potentiates CCK action

Answer 11

ACh released from the vagus

Question 12

what cells in the duodenum release secretin

Answer 12

S cells

this stimulates bicarbonate secretion

Question 13

what stimulates secretin release

Answer 13

arrival of acidic chime in the duodenum

Question 14

what two substances potentiate secretin action

Answer 14

ACh and CCK

Question 15

what is the name of solubised digestion products

Answer 15

micelles

Question 16

what stimulates bile secretion

Answer 16

CCK (duodenal 1 cells and jejunal mucosa) and parasympathetic supply

Question 17

when is bile ejected

Answer 17

30 mins after a meal

Question 18

what is the function of CCK

Answer 18

contraction of the gall bladder
relaxation of the sphincter of Oddi
secretion of pancreatic enzymes
secretion of bicarbonate
growth of exocrine pancreas and gall bladder
inhibition of gastric emptying

Question 19

how are bile salts returned to the liver

Answer 19

by the enterohepatic portal circulation

extracted by hepatocytes

Question 20

what do micelles contain

Answer 20

cholesterol,
monoglycerides, lysolecithin and free fatty
acids- core

surface coating of bile salts

Question 21

what are the circular folds of Keckring

Answer 21

folds on the surface of the small intestine with villi projecting aka plicae circulares

Question 22

what cells cover the surface of the villi

Answer 22

enterocytes and goblet cells

apical surface of epithelial cells are covered by microvilli brush border

Question 23

what type of carbohydrate can be absorbed

Answer 23

monosaccharides only- glucose, galactose and fructose

Question 24

how are glucose and galactose absorbed

Answer 24

sodium dependant co transport via SLGT1

Question 25

how is fructose absorbed

Answer 25

facilitated diffusion - GLUT5

Question 26

What do endopeptidases do

Answer 26

hydrolyse the interior peptide

bonds of proteins

Question 27

what do exopeptidases do

Answer 27

hydrolyse one amino acid at a time

Question 28

name the pancreatic proteases secreted as inactive precursors

Answer 28

Trypsinogen
Chymotrypsinogen
Proelastase
ProcarboxypeptidaseA
 Procarboxypeptidase B

Question 29

what enzyme activates trypsinogen

Answer 29

brush border enzyme enterokinase

trypsis then catalyses the conversion of other inactive precursors