Lecture 6: Digestion and Reabsorption of Carbs and Lipids

Question 1

What are the two paths for absorption of carbohydrates and proteins

Answer 1

Transcellular
Paracellular

Question 2

Transverse folds of intestinal mucosa
Folds are large circular folds of mucosa

Answer 2

Folds of Kerckring

Question 3

Villi line

Answer 3

Lumen of small intestine

Question 4

Villi are lined by what kind of cells

Answer 4

Epithelial cells and goblet cells

Question 5

What do goblet cells secrete?

Answer 5

Mucus

Question 6

Where are villi longest and shortest?

Answer 6

Longest in duodenum
Shortest in terminus of ileum

Question 7

What form the brush border?

Answer 7

The surface of epithelial cells lined with microvilli

Question 8

Folds + villi =

Answer 8

Microvilli

Question 9

What fold is SA increased by microvilli

Answer 9

600

Question 10

What is turnover rate of epithelial cells

Answer 10

Every 3-6 days

Question 11

Natural diet of horse, cattle, sheep

Answer 11

Grass

Question 12

Grass is high in

Answer 12

Cellulose

Question 13

Grain is high in

Answer 13

Starch

Question 14

Chicken and pigs usually fed diets high in

Answer 14

Starch

Question 15

Dogs are classified as

Answer 15

Omnivores

Question 16

What diet do dogs do well on?

Answer 16

Diets of starch + soluble fibers

Question 17

What is the primary source of energy for most cells?

Answer 17

Glucose

Question 18

Monosaccharides definition

Answer 18

Simple sugars

Question 19

Glucose, fructose, galactose, ribose are examples of

Answer 19

Monosaccharides

Question 20

Sucrose, maltose, lactose are examples of

Answer 20

Disaccharides

Question 21

Disaccharides definition

Answer 21

2 monosaccharides

Question 22

Polysaccharides definition

Answer 22

Complex chains of sugars

Question 23

Starch, cellulose, glycogen, hemicellulose are examples of

Answer 23

Polysaccharides

Question 24

All ingested carbs must be digested to what for absorption?

Answer 24

Monosaccharides

Question 25

What absorbs monosaccharides?

Answer 25

Enterocytes

Question 26

How does digestion of carbohydrates begin?

Answer 26

Enzymatic cleavage makes chains shorter

Question 27

What cleaves internal linkages of amylose (alpha 1,4 glycosidic bonds) in starch digestion?

Answer 27

Alpha-amylase

Question 28

What cleaves linear or branched portions of amylose or glycogen in starch digestion?

Answer 28

Glucoamylase

Question 29

In starch digestion, what is used to digest oligosaccharides? AKA Brush border enzyme

Answer 29

Alpha-dextrinase

Question 30

What are the brush border enzymes in starch digestion?

Answer 30

Alpha-dextrinase, maltase, sucrase, lactase

Question 31

What does maltase (brush border enzyme) do in starch digestion?

Answer 31

Converts maltose to 2 glucose units

Question 32

What are the monosaccharides for absorption?*

Answer 32

Glucose, galactose, fructose

Question 33

What enzymes digest cellulose/hemicellulose?

Answer 33

No mammalian enzymes for digesting these

Question 34

What transports both glucose and galactose from intestinal lumen to enterocyte?

Answer 34

SGLT 1 (Na+/glucose co-transporter)

Question 35

What transport method is using to transport fructose from intestinal lumen into enterocyte?

Answer 35

Facilitated diffusion

Question 36

What transporter is fructose specific?

Answer 36

GLUT 5

Question 37

What transport method is using to transport glucose, galactose, fructose from enterocyte into blood?

Answer 37

Facilitated diffusion

Question 38

What specific transporter is used to transport glucose, galactose, and fructose from enterocyte into blood?

Answer 38

GLUT 2

Question 39

What is deficient in lactose intolerance?

Answer 39

Lactase

Question 40

What domestic species have dietary requirements for essential amino acids?

Answer 40

Dogs, cats, chickens, pigs, horses

Question 41

What domestic species have dietary protein requirement only?

Answer 41

Cattle, sheep, goats

Question 42

Why do cattle, sheep, goats only have a dietary protein requirement?

Answer 42

Microbes can take the dietary protein and make essential AA which will be absorbed in SI

Question 43

In species that have dietary requirements for essential amino acids, what must be special about the protein in their diets?

Answer 43

Protein must be high quality

Question 44

What does high quality protein mean?

Answer 44

Protein with essential amino acid profile

Question 45

What form are amino acids usually provided in?

Answer 45

Protein

Question 46

Essential AA P.V.T

Answer 46

Phenylalanine Valine Threonine

Question 47

Essential AA T.I.M

Answer 47

Tryptophan Isoleucine Methionine

Question 48

Essential AA H.A.L.L

Answer 48

Histidine Arginine Leucine Lysine

Question 49

Digestion of protein in the stomach is ultimately completed by

Answer 49

Endopeptidases and exopeptidases

Question 50

What do exopeptidases do

Answer 50

Hydrolyze 1 AA at a time from C terminal end

Question 51

Protein digestion begins where

Answer 51

Stomach

Question 52

When is pepsinogen activated to pepin?

Answer 52

When pH is 1-2

Question 53

Pepsin exopeptidase or endopeptidase?

Answer 53

Endopeptidase

Question 54

What does endopeptidases do?

Answer 54

Hydrolyze interior bonds

Question 55

What does HCl do to proteins?

Answer 55

Causes them to unfold and expose their peptide bonds to pepsin

Question 56

In young ruminants, chief cells produce

Answer 56

Rennin

Question 57

Enzyme that coagulates milk + reduces (decreases) passage rate in young ruminants

Answer 57

Rennin

Question 58

Inactive enzymes

Answer 58

Zymogens

Question 59

What does SI utilize in protein digestion?

Answer 59

Pancreatic proteases and brush border proteases

Question 60

When digesta enters SI, what is released?

Answer 60

CCK

Question 61

When digesta enters SI, CCK is released, which causes the release of

Answer 61

Zymogens

Question 62

SI endopeptidases

Answer 62

Trypsin, chymotrypsin, elastase

Question 63

SI exopeptidases

Answer 63

Carboxypeptidases A and B

Question 64

What activates trypsinogen to form trypsin?

Answer 64

Enterokinase

Question 65

What does trypsinogen form when activated?

Answer 65

Trypsin

Question 66

What breaks down the proteins in the SI? Name all

Answer 66

Trypsinogen, chymotrypsinogen, proelastase, procarboxypeptidase A and B

Question 67

What activates other zymogens after initial release?

Answer 67

Trypsin

Question 68

What is the final protein digestion step in SI?

Answer 68

Aminopeptidases at the brush border break down peptides further

Question 69

AA move across basolateral membrane via

Answer 69

Facilitated diffusion

Question 70

Carb products of digestion

Answer 70

Glucose Galactose Fructose

Question 71

Protein products of digestion

Answer 71

Amino acids Dipeptides Tripeptides

Question 72

Carbohydrate absorption mechanisms

Answer 72

Na+-glucose co transporter Na+-galactose co transporter Facilitated diffusion

Question 73

Protein absorption mechanisms

Answer 73

Na+-amino acid co-transporter H+-dipeptide co-transporter H+-tripeptide co-transpower

Question 74

Loss of appetite, vomiting, weakness, abdominal pain, dehydration, diarrhea are symptoms of

Answer 74

Pancreatitis

Question 75

Prematurely activated enzymes can lead to local damage of exocrine pancreas, which leads to?

Answer 75

Pancreatitis

Question 76

Insufficient production and secretion of digestive enzymes (which can be caused by long-term pancreatitis) is a cause of what?

Answer 76

Exocrine pancreatic insufficiency

Question 77

Destruction of cells producing digestive enzymes is a cause of what?

Answer 77

Exocrine pancreatic insufficiency

Question 78

Lack of digestion, malabsorption, weight loss, nutrient deficiencies are all symptoms of

Answer 78

Exocrine pancreatic insufficiency

Question 79

Defect or absence of Na+/amino acid co-transporter is a cause of

Answer 79

Cystinuria

Question 80

Crystal formation and calculi, urinary blockages, are symptoms of

Answer 80

Cystinuria