[4] Digestion and Absorption

Question 1

Small Intestine Surface Area gets amplified how many times?

Answer 1

600x

Question 2

Composition:

Sucrose
Lactose
Maltose

Answer 2

Glu-Fru
Glu-Gal
Glu-Glu

Question 3

Carbohydrates compose what % of our diet

Answer 3

50-60%

Question 4

What is more effective? Ptaylin or Pancreatic Amylase?

Answer 4

Ptyalin: 20-40%
Pancreatic Amylase: 50-80%

% Digestion

Question 5

Triglycerides require _____ and _____ to become ____ and ____

Answer 5

Colipase and Lipase

Fatty Acids and Monoglycerides

Question 6

Phospholipids require _____ to become ____ and ____

Answer 6

Phospholipase A2

Fatty Acids and Lysolecithin

Question 7

In a normal intestine which is greater? Absorption or Secretion?

Answer 7

Absorption > Secretion

Question 8

SCFA’s are taken up by?

Answer 8

Colonocytes

Question 9

Fat-Soluble Vitamins

Answer 9

ADEK

Question 10

Where are Bile Acids and Vitamin B12 absorbed?

Answer 10

Ileum

Question 11

What do you need to properly absorb Calcium?

Answer 11

Vitamin D

Question 12

Should you take calcium before, during, or after meals?

Answer 12

2 hours after

Some food can interfere with Ca uptake

Question 13

What state is it easier to uptake iron in? Ferrous or Ferric?

Answer 13

Ferrous (Fe2+)

Question 14

What can decrease iron absorption?

Answer 14

Tannins (Non-herbal Teas)

Phytates, wheat, and other cereals

Question 15

What is the storage form of iron in the body?

Answer 15

Ferritin

Question 16

Best site of absorption of Carbohydrates?

Answer 16

Duodenum

Question 17

[Effect on Absorption]

1. Lipid Solubility
2. Size
3. Presence of Special Carrier
4. Electrochemical Gradient

Answer 17

1. • = +
2. Smaller = +
3. W/ special carriers = +
4. • = +

Question 18

Effect of Plicae Circulares on Surface Area

Answer 18

x3

Question 19

Effect of Villi on Surface Area

Answer 19

x10

Question 20

Effect of Microvilli on Surface Area

Answer 20

x20

Question 21

How is sucrose digested?

Answer 21

Membrane Digestion

Occurs at the immediate vicinity of the brush border

Question 22

How are proteins digested?

Answer 22

Luminal Digestion

With proteases occuring within GI lumen

Question 23

How are some tri and dipeptides absorbed?

Answer 23

Intracellular Hydrolysis

Question 24

How are triglycerides taken up?

Answer 24

Luminal hydrolysis by lipase -> Simple diffusion to enterocyte -> Intracellular resynthesis into triglyceride

Question 25

[T/F] Lipids have brush border digestion

Answer 25

F

Question 26

How many g/day of Carbohydrates should be consumed?

Answer 26

250-800g/day

Question 27

Luminal Digestion Enzymes Components

Answer 27

Ptyalin: 20-40% | Pancreatic Amylase: 60-80%

Question 28

Enzyme found in the mouth

Answer 28

Salivary alpha-amylase

Question 29

% of starch digestion in the mouth

Answer 29

20%

Question 30

Enzyme found in the Duodenum

Answer 30

Pancreatic alpha-amylase

Question 31

What breaks down disaccharides in the duodenum?

Answer 31

Brush Borders

Question 32

How are Glucose and Galactose transported?

Answer 32

Enter through the apical side together with Na+ through SGLT-1 (Sodium Glucose Transporter 1)

Question 33

How many sodium ions to one glucose or galactose?

Answer 33

2 Na+ : 1 GLU/GAL

Question 34

How is Fructose absorbed?

Answer 34

GLUT-5

Question 35

How do Glucose, Galactose, and Fructose pass the basolateral side to the interstitial space?

Answer 35

GLUT-2 Facilitated Diffusion

Question 36

Order of Absorbability of Monosaccharides

Answer 36

``` Galactose Glucose Fructose Mannose Xylose Arabinose ```

Question 37

Daily Dietary Protein Requirement

Answer 37

0.5-0.7g/kg

Question 38

[Endogenous Proteins] Amount per day? Where are they from?

Answer 38

30-40g/day From secretory proteins and desquamated cells Sources of the protein in stools

Question 39

[Exogenous Proteins] Amount per day? Where are they from?

Answer 39

70-100g/day | Dietary Proteins

Question 40

Where does protein digestion start?

Answer 40

Stomach

Question 41

Proteins are acted upon by _____ to produce _______?

Answer 41

Pepsin Proteoses, peptones, and polypeptides

Question 42

Proteoses, peptones, and polypeptides are acted upon by ______ to produce _______?

Answer 42

Trypsin, chymotrypsin, carboxypolypeptidase, proelastase Polypeptides + Amino Acids

Question 43

Polypeptides + Amino Acids are acted upon by _____ to produce ______

Answer 43

Peptidases Amino Acids

Question 44

Complete digestion of food requires?

Answer 44

Pancreatic and Brush Border Enzymes

Question 45

What activates Trypsin?

Answer 45

Enterokinase

Question 46

Where are enterokinases produced?

Answer 46

Duodenum and Jejunum

Question 47

What is the transport protein for di/tripeptides?

Answer 47

PepT1

Question 48

Common Cause of Fat Malabsorption

Answer 48

Obstruction of common bile duct or tumor in the pancreatic head/bile duct

Question 49

Function: Colipase

Answer 49

Anchors lipase displayed by bile acids

Question 50

Phospholipids are acted upon by ______ to become ______ and ______

Answer 50

Phospholpase A2 Fatty Acids and Lysolecithin

Question 51

Cholesterol Esters (CE) are acted upon by _______ to become _______ and ________

Answer 51

Cholesterol Esterase Fatty Acids and Cholesterol

Question 52

Gastric Lipase is responsible for what % of fat digestion?

Answer 52

15%

Question 53

Can chylomicrons enter the capillary?

Answer 53

No, because they are too large. Only Medium-Chain FAs can go into capillaries

Question 54

Define: Steatorrhea

Answer 54

Failure of fat absorption due to the lack of bile

Question 55

Where is sodium mainly absorbed?

Answer 55

Small Intestine and Colon

Question 56

Where are vitamins absorbed?

Answer 56

Proximal Portion of the Small Intestine