Digestion

Question 1

What form do fats, proteins, and complex carbs have to be broken down into before they are digested?

Answer 1

Amino Acids, monomeric sugars, monoglycerides.

Question 2

Saliva: digestion of carbohydrates?

Answer 2

salivary alpha-amylase (by serosal cells)

Question 3

Saliva: digestion of lipids?

Answer 3

lingual lipase (by mucosal cells)

Question 4

Saliva: other secretions

Answer 4

Mucin (by mucosal cells), Ca2+

Question 5

How long does it take for the epithelium to renew?

Answer 5

2-3 days.

Question 6

Saliva: best known stimuli

Answer 6

cholinergic fibers

Question 7

Pancreas: digestion of carbs

Answer 7

pancreatic alpha-amylase

Question 8

Pancreas: digestion of lipids

Answer 8

pancreatic lipase (acts on surface of micelles)
pro-colipase (anchors enzyme, prevents denaturation)
pro P-lipase A2 (activated by trypsin, helps emulsify dietary fat)
cholesterol esterase (produces FFA and cholesterol)
nonspecific esterase

Question 9

Pancreas: digestion of proteins

Answer 9

trypsinogen
chymotrypsinogen (activated by trypsin)
Procarboxy
pepidase A and B (activated by trypsin)
Proelastase (activated by trypsin)

Question 10

Pancreas: digestion of nucleic acids

Answer 10

RNAse, DNAse

Question 11

Pancreas: other

Answer 11

mucin
Na bicarbonate
trypsin inhibitor

Question 12

Pancreas: best known stimuli

Answer 12

secretin from duodenum (for bicarb)

cholecystokinin (for enzymes)

Question 13

Stomach: digestion of lipids

Answer 13

gastric lipase (impt for infants digesting emulsified milk fat)

Question 14

Stomach: digestion of proteins

Answer 14

H+ denaturation

pepsinogen (chief cells)

Question 15

stomach: other

Answer 15

HCl (Parietal/oxyntic cells)
Mucin (by mucosal cells)
intrinsic factor (parietal cells)

Question 16

Stomach: best known stimuli

Answer 16

cholinergic fibers (vagus)
gastrin (G cells - endocrine)
histamine (ECL cells-paracrine)

Question 17

Bile: digestion of lipids

Answer 17

conjugated cholic (aka bile) acids
P-lipids
cholesterol

Question 18

Bile: other

Answer 18

Na Bicarb
bilirubin
conjugated substances

Question 19

Bile: best known stimuli (to empty gallbladder)

Answer 19

cholecystokinin

Question 20

Intestinal secretion: name 3

Answer 20

Na bicarb
NaCl (epithelial cells)
Mucin

Question 21

Intestinal secretion: best known stimuli

Answer 21

secretin

Question 22

Intestinal brush border: digestion of carbs

Answer 22

sucrase-maltase-isomaltase

lactase (absence -> lactose intol)

Question 23

Intestinal Brush Border: digestion of lipids

Answer 23

recombination of FA+

monoacylglycerol

Question 24

Intestinal Brush Border: digestion of proteins

Answer 24

exopeptidases

Question 25

Intestinal Brush Border: digestion of nucleic acids

Answer 25

nucleotidases | nucleosidases

Question 26

Intestinal Brush Border: other

Answer 26

enteropeptidase, which activates trypsin, which initiates cascade of proteolytic activation of all pancreatic pro-enzymes.

Question 27

Bacteria: digestion of carbs

Answer 27

cellulose

Question 28

Bacteria: other

Answer 28

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Question 29

absorption of carbs

Answer 29

glucose and galactose: Na+ symport

Question 30

absorption of lipids

Answer 30

chylomicrons

Question 31

absorption of proteins

Answer 31

amino acids: Na symport | di/tri peptides: H symport

Question 32

What is required for intestinal absorption of Vit B12?

Answer 32

intrinsic factor (parietal cells of stomach)

Question 33

How does pepsinogen become activated?

Answer 33

Activated to pepsin upon contact with acid

Question 34

4 roles of stomach acidity

Answer 34

kills organisms denatures proteins activates pepsinogen --> pepsin stimulates duodenal secr of secretin

Question 35

2 ways to inhibit stomach acid secretion

Answer 35

H2 receptor agonists (ex Zantac) | Proton pump inhibitors (ex Prilosec)

Question 36

Acidity of chyme stimulates what in duodenum

Answer 36

secretion of secretin (which then stims secr of sodium bicarb by pancreas and intestine)

Question 37

Peptides and fats in chyme stimulate what in duodenum

Answer 37

secretion of CCK

Question 38

secretion of CCK from the duodenum stimulates what?

Answer 38

secretion of enzymes, by fusion of storage granules with apical portion of plasma membrane

Question 39

many digestive enzymes are secreted as proenzymes: which are secreted in active form?

Answer 39

alpha-amylase, DNase, RNase

Question 40

absorption of fructose?

Answer 40

not well absorbed, so excess of this sugar can cause diarrhea

Question 41

Why are glucose and amino acids helpful in oral rehydration therapy of cholera patients?

Answer 41

They are absorbed via Na -symports and thus promote absorption of NaCl.