Pancreatic secretions, carbohydrate/vitamin/mineral absortion Peyer patches, bile p. 282-283

Question 1

pancreatic secretions: what is the role of alpha-amylase?

Answer 1

starch digestion

Question 2

pancreatic secretions: what enzyme digests starch?

Answer 2

alpha-amylase

Question 3

pancreatic secretions: what is the role of lipase?

Answer 3

fat digestion

Question 4

pancreatic secretions: which enzyme digests fat?

Answer 4

lipase

Question 5

pancreatic secretions: what is the rol of trypsinogen?

Answer 5

converted to trypsin -> activation of other proenzymes and cleaving of more trypsinogen (positive feedback)

Question 6

is alpha-amylase secreted in the active form?

Answer 6

yes

Question 7

pancreatic secretions: what is the role of proteases?

Answer 7

protein digestion

Question 8

name 4 types of proteases

Answer 8

trypsin, chymotrypsin, elastase, carboxypeptidases

Question 9

how are proteases secreted (enzymes or proenzymes), and how do you call this?

Answer 9

proenzymes, zymogens

Question 10

by which enzymes does trypsinogen get converted to trypsin?

Answer 10

enterokinease, enteropeptidase

Question 11

where are enterokinase/enteropeptidase located? (the enzymes that convert trypsinogen into trypsin)

Answer 11

in the brush border of the duodenum and jejunum

Question 12

what kind of saccharides are absorbed by enterocytes? poly or mono?

Answer 12

monosaccharides (glucose, galactose, fructose)

Question 13

name 3 kinds of monosaccharides

Answer 13

glucose, fructose, galactose

Question 14

via which transporter is fructose taken up by the enterocyte? and via what type of diffusion?

Answer 14

GLUT5, facilitated diffusion

Question 15

via which transporter is galactose and glucose taken up by the enterocyte? and what is this dependent on (what type of transport)?

Answer 15

SGLT1, Na+ dependent

Question 16

via what transporter are all monosaccharides (glucose, fructose, galactose) transported from the enterocyte to the blood?

Answer 16

GLUT2

Question 17

what is the d-xylose test?

Answer 17

d-xylose is a simple sugar that is passively absorbed in proximal small intestine. blood/urine levels decrease with mucosal damage. (normal in pancreatic insufficieny)

Question 18

vitamin and mineral deficiencies develop in patients with which conditions?

Answer 18

small bowel disease, bowel resection, bariatric surgery (e.g. vitamin B12 deficiency after terminal ileum resection)

Question 19

small bowel disease, bowel resection, bariatric surgery. can lead to what?

Answer 19

vitamin and mineral deficiency

Question 20

ileum resection: which deficiency?

Answer 20

vitamin b12

Question 21

how is iron absorbed and where?

Answer 21

as Fe2+ in duodenum

Question 22

where is folate absorbed?

Answer 22

small bowel

Question 23

where is vitamin b12 absorbed? what does this require?

Answer 23

terminal ileum (along with bile salts), requires intrinsic factor

Question 24

what are Peyer patches?

Answer 24

unencapsulated lymphoid tissue
found ileum (lamina propria and submucosa)

Question 25

unencapsulated lymphoid tissue found in lamina propria and submucosa of ileum

what is this?

Answer 25

Peyer patches

Question 26

where are Peyer patches located?

Answer 26

ileum (lamina propria and submucosa)

Question 27

what type of specialized cells do Peyer patches contain? what do they do?

Answer 27

M cells (microfold cells), present antigens to immune cells

Question 28

what do M cells in the Peyer patches do?

Answer 28

present antigens to immune cells

Question 29

what do B cells inside Peyer patches differentiate into? what do they secrete? where do they reside?

Answer 29

plasma cells, secrete IgA, reside in lamina propria

Question 30

what happens to IgA secreted by plasma cells in the lamina propria?

Answer 30

it gets transported into gut to deal with intraluminal antigens

Question 31

mnemonic IgA in the gut?

Answer 31

IgA = Intra-gut-Antibody

Question 32

bile: what is this composed of?

Answer 32

bile salts. phospholipids, cholesterol, bilirubin, water, ions

Question 33

what can bile acids be conjugated to? what is the results?

Answer 33

glycine or taurine, makes them water soluble

Question 34

what makes bile salts water soluble?

Answer 34

conjugation to glycine or taurine

Question 35

what is the function of cholesterol 7alpha-hydroxylase ?

Answer 35

rate limiting step of bile acid synthesis

Question 36

what are bile salts?

Answer 36

bile acids conjugated to taurine or glycine to make them water soluble

Question 37

what are the functions of bile? (3)

Answer 37

1. digestion/absorption of lipids and fat-soluble vitamins
2. bilirubin and cholesterol excretion
3. antimicrobial activity (via membrane disruption)

Question 38

what is the body’s 1st means of eliminating bilirubin and cholesterol?

Answer 38

via bile

Question 39

decreased absorption of enteric bile salts at the distal ileum.

what does this lead to? (2 things)

Answer 39

abnormal fat absorption, and bile acid diarrhea

Question 40

decreased absorption of enteric bile salts at the distal ileum.

name 2 examples of diseases that have this decreased absorption?

Answer 40

short bowel syndrome, crohn

Question 41

what happens with calcium/oxalate when there’s decreased fat absorption in the gut?

Answer 41

calcium binds normally oxalate, but now binds fat instead. oxalate absorbed by gut -> calcium oxalate kidney stones

Question 42

decreased absorption of enteric bile salts at the distal ileum leads to:
1) abnormal absorption of fat
2) bile acid diarrhea

what else can happen?

Answer 42

calcium oxalate kidney stones

(calcium binds normally oxalate, but now binds fat instead. oxalate absorbed by gut)