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Flashcards in Digestion and absorption Deck (43):
1

What is the site of B12 absorption?

Ileum

2

What are the cells that produce intrinsic factor?

Parietal cells of the stomach

3

Are oligosaccharide or polysaccharides absorbed directly?

No--digested to monosaccharides first

4

Where is the first primary site of polysaccharide digestion? What is the enzyme utilized here?

Lumen of the intestine

alpha-amylase

5

What stimulates the release of alpha-amylase? Where does the enzyme come from?

Ach and CCK

Pancreas

6

Where are the lactase, maltase, and isomaltase enzymes found?

On the brush border of the intestines

7

What are the glucose transporters utilized in the intestine?

Luminal side: SLGT1, GLUT5

Intracellular side: GLUT2

8

SGLT1 can move what across the membrane?

Na, Glu, Glc.

9

What is the substrate for GLUT5?

Fructose

10

Where does protein digestion begin? What is the enzyme utilized here? Where does this enzyme from from?

Stomach

Pepsin from chief cells

11

What is the function of gastrin?

Promotes acid secretion, and delays gastric emptying

12

What are the enzymes in the intestines that digest peptides? Where do these come from? What causes their release?

Trypsin--pancreas in response to CCK

Brush border peptidases

13

Are oligopeptide able to be absorbed, or do they need to be broken down fully to amino acids?

Can absorb oligopeptides

14

What is the transporter that can move small oligopeptides across the apical membrane? What is cotransported?

PEP1, uses H ions co transport

15

What is the transporter that can move amino acids across the apical membrane? What is cotransported?

B transporter
Na

16

Where do lipids begin to be digested? What are the enzymes utilized here?

Lumen of the stomach

Lingual lipase
Gastric lipase
Emulsification

17

What are the enzymes that digest lipids in the lumen of the duodenum?

Pancreatic lipase
Co-lipase
Emulsification
(Bile)

18

What inactivates gastric lipases?

pancreatic proteases and alkaline conditions

19

What is the **primary** site of lipid digestion?

Lumen of the duodenum

20

What is the cell types that responds to FAs in the duodenum? What does it release?

I cells, CCK

21

What is the function of colipase?

Regulatory protein that anchors lipase to fatty droplets---IT HAS NO ENZYMATIC ACTIVITY

22

What are the fat soluble vitamins? A defect in what leads to a deficiency?

A, D, E, K
Reduce bile synthesis or secretion

23

What is the transporter for cholesterol and FAs?

NPC1L1

24

What are chylomicrons?

MIxture of lipids in intestinal epithelial cells

25

What do chylomicrons combine with to be transported through the blood?

Lipoproteins

26

Where is the intrinsic factor receptor expressed?

Ileum

27

What is the protein that transports B12 in the body?

transcobalamin

28

Where is B12 stored? Secreted?

Liver and secreted in the bile

29

What happens to parietal cells as we age? Problem with this?

Less of them = less IF = less B12

30

What is the cause of pernicious anemia?

Several important pathologies are related to either an actual or a
functional vitamin B12 deficiency. Actual deficiency refers to a lack of vitamin B12 in
the diet whereas functional deficiency refers to an inability to absorb or otherwise
metabolize the vitamin.

31

What regulates the expression of the Ca transporter in the intestines?

Vit D

32

Lactose intolerance is due to what? What are the symptoms that this causes?

Lactase deficiency in the lumen of the intestines

Osmotic diarrhea--bacterial gas production

33

Lactose = what two monomers?

Glucose + galactose

34

Why does gastroparesis lead to poor glycemic control?

Irregular dumping of food into the intestines, causing inefficient absorption. This can change the amount of medication absorbed.

35

What is the role of folic acid?

Needed for DNA synthesis--thus will be upregulated if there is less B12, but no good

36

What transporter is utilized to transport glu, glc, and fructose across the basolateral cell membrane, into the interstitium?

GLUT-2

37

What is the transporter that absorbs cholesterol?

Neimann Pick C1-like1 (NPC1L1)

38

What is the importance of folic acid and B12? What is the primary symptom of a folate deficiency?

Used in DNA synthesis and cell division

Anemia d/t loss of RBC production

39

Colbalamin = ?

Vit B12

40

Why is ferric ion not absorbed from the intestines?

It precipitates out at pHs above 3

41

What is the vitamin that reduces Fe 3+ to Fe2+?

C

42

What is the protein carrier of Fe?

Transferrin

43

What is the transporter that absorbs Fe from the intestines?

divalent cation transporter 1 (DCT-1)