Digestion Of Protein And Carbohydrates Flashcards

1
Q

What stimulates the secretion of pancreatic amylase?

A

CCK

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which enzymes are involved in the digestion of starch to oligosachharides?

A

Salivary amylase

Pancreatic amylase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which Oligosaccharides are produced form the hydrolysis of starch?

A

Alpha limit dextrins

Maltose

Maltotriose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the three brush border oligosaccharides?

A
  1. lactase
  2. maltase
  3. sucrase-isomaltase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where does brush border digestion for oligosaccharides mainly occur?

A

Proximal Jejunum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which enzymes are involved in the digestion of alpha limit dextrins?

A

Isomaltase

Maltase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the products of lactose digestion?

A

Galactose

Glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the products of sucrose digestion?

A

Glucose

Fructose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does the absorption of glucose, galactose and fructose occur in the small intestine?

A
  1. Uptake across the apical membrane into the epthelial cell
    1. Glucose, Galactose- Na/glucose transporter SLGT1
      • secondary active transport, glucose inlux occurs against glucose concentration gradient, Na+ gradient maintained by basolateral Na-K pump
    2. Fructose- GLUT5 transporter- facilated diffusion
  2. Exit across the basolaterla membrane
    • facilated sugar transporter GLUT2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What transporter is involved in the transport of glucose and galactose across the apical cell membrane?

A

SLT-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does SLT-1 transporter do?

A

Transport glucose and galactose across apical cell membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What transporter is involved in the transport of fructose across apical cell membrane?

A

GLUT-5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the transport of glucose and galactose called and why?

A

secondary active transport because its Na driven

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does the three monosaccharides exit the basolateral membrane

A

through GLUT-2 transporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the symptoms of lactase deficiency after ingestion of lactose

A

GI symptoms, diarrhea and cramps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why does individuals with primary lactase deficiency have increased breath H2

A

Non absorbed lactose is metabolised by colonic bacteria to form H2, which is absorbed into the blood and excreted by the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which dietry proteins are absorbed intact?

A

Antigenic proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Who can absorb intact proteins in substantial amounts?

A

Neonates- up to 6 months. From colostrum through endocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the first pathway for digestion of proteins

A

Digestion of proteins into peptides by luminal enzymes. Digestion of peptides into amino acids by luminal enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the second pathway for digestion of proteins

A

Digestion of protein into peptides by luminal enzymes Digestion of peptides into amino acids by brush border enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the third pathway for digestion of proteins

A

Digestion of proteins into oligopeptides by luminal enzymes Oligopeptides are taken up by enterocyte Digestion into intracellular amino acids by cytosolic enzymes Transport across the basallateral membrane into the blood by transporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the fourth pathway for digestion of proteins

A

Digestion of proteins into oligopeptides by luminal enzymes Oligopeptides are taken up by enterocyte Move directly into the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does gastric chief cells secrete

A

Pepsinogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How does pepsinogen get activated

A

Low intragastric pH

25
Q

What is pepsin

A

An endopeptidase with primary specificity for peptide linkages of aromatic and larger amino acids

26
Q

What are the 5 pancreatic proenzymes

A

Trypsinogen Chymotrypsinogen Proelastase Procarboxylase A Procarboxylase B

27
Q

How does the pancreatic proenzymes activate

A

Trypsinogen by enterokinase. The rest by trypsin

28
Q

What are the 5 pancreatic enzymes

A

Trypsin Chymotrypin Elastase Carboxylase A Carboxylase B

29
Q

What are the products of endopeptidase

A

oligosachharides with 2 to 6 amino acids

30
Q

What are the products of exopeptidase

A

Amino acids

31
Q

Which pancreatic enzymes are endopeptidase

A

Tryspin Chymotrypsin Elastase

32
Q

Which pancreatic enzymes are exopeptidase

A

Carboxylase A Carboxylase B

33
Q

For individuals with primary lactase deficiency, what does ingestion of lactose have on plasma glucose concentration?

A

Smaller rise in plasma glucose

34
Q

What does brush border peptidase have an affinity towards?

A

relatively larger oligopeptides- 3-8AAs

35
Q

What does cytoplasmic peptidase primarily hydrolyse?

A

di and tri peptides

36
Q

What transporter is responsible for the uptake of luminal oligopeptides?

A

PEPT-1

37
Q

What system is responsible for the uptake of cationic and cystine?

A

b0

38
Q

What does b0 system involve?

A

an Na+ independent transporter for cationic amino acids and cystine. This transporter is an antiporter coupling the uptake to the efflux of neutral amino acids

39
Q

What system is responsible for the uptake of neutral amino acids?

A

B0

40
Q

What does B0 system involve?

A

an Na+ dependent transporter

41
Q

What system is responsible for the transport of glycine and proline?

A

IMINO system

42
Q

What does IMINO system involve?

A

Na+ dependent IMINO system and H+ dependent imino acid carrier for the transport of glycine and proline

43
Q

What system is responsible for the transport of anionic amino acids?

A

EAAT3 (XAG)

44
Q

Why is the transport system for anionic amino acids named XAG?

A

because it involves a Na+ dependent transporter for aspartate and glutamate

45
Q

Which transporter is involved in the transport of cationic amino acids across the basolateral membrane?

A

heteromeric antiporter 4F2hc/y*LAT1

46
Q

Which transporter is involved in the efflux of neutral amino acids

A

4F2hc independent LAT transporters of the SLC43 family

47
Q

Hartnup and cystinuria- inheritance

A

autosomal recessive

48
Q

What transport is affected in Hartnup and cysteria?

A

Apical membrane amino acid trasnport

49
Q

What are the clinical signs associated with Hartnup disease?

A

Most evident in children- Skin changes of pellagra, cerebellar ataxia and psychiatric abnormalities

50
Q

Which systems are affected in Hartnup diesease?

A

System B- neutral amino acids uptake However, oligopeptides containing neutral amino acids are absorbed normally in Hartnup disease

51
Q

What are the clinical signs assocaited with cystinuria?

A

kidney stones

52
Q

Which systems are affected in Cystinuria?

A

b0+ and B0+ system Cysteine and basic amino acids import are affected

53
Q

Why is there lack of evidence of protein deficiency in Hartnup and Cystinuria?

A

More than one transport system for different amino acids Seperate transporter for oligopeptides

54
Q

What are the two routes responsible for the uptake of intact protein?

A

Enterocyte-phagocytosis M cells

55
Q

What happens in Enterocyte phagocytosis?

A

A small amount of intact protein makes it to the interstitial space. The vast majority is degraded in lysosomes

56
Q

Where are M cells located?

A

Payers patches. They have few microvilli and are specialised for protien uptake

57
Q

What does M cells do?

A

They package ingested proten in Clathrin-coated vesicles, which they secrete at their basolateral membranes into the lamina propria There, the immunocompetent cells process the target antigen s and transfer them to lymphocytes to initiate an immune response

58
Q

Give some examples of insoluble dietry fibre

A

Cellulose and hemicellulose

59
Q

Give some examples of soluble fibre

A

Pectins, gums and mucilage