Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GEMS > GI Nutrient Digestion & Absorption > Flashcards

GI Nutrient Digestion & Absorption Flashcards

1
Q

Where is the greatest amount of absorption? What is absorbed?

A

Duodenum
CHOs, proteins, lipids

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

Where are fatty acids absorbed?

A

Colon

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

What is absorbed in the small intestine?

A

Carbs, proteins, lipids (greatest in duodenum)

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

Where are Ca++, Fe+++, folate absorbed?

A

Actively absorbed in the duodenum

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

Where is bile acid absorbed?

A

Along the entire small intestine.

Only active absorption in ileum

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

Where is B12 (cobalamin) absorbed

A

Ileum (ONLY)

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

What process is defective in Celiac Disease?

A

Fat absorption & Lactose hydrolysis

In the duodenum and jejunum

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

What process is defective in Chronic pacreatitis?

A

Fat digestion

In the exocrine pancreas

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

What process is defective in Crohn disease (or surgical resection) of ileum?

A

Cobalamin & bile acid absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What process is defective in primary lactase deficiency?

A

Lactose hydrolysis in the small intestine

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

What occurs as a result of intraluminal hydrolysis?

A

Starch breaks down into oligosaccharides by hydrolysis via salivary a-amylases & pancreatic a-amylases

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

Amylases are produced in what cells?

A

Acinar cells of salivary glands & pancreas

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

Carb Metabolism: What are the products of intraluminal hydrolysis (step 1)?

A
  1. Linear glucose oligomers
  2. Maltotriose (linear glucose trimer)
  3. Maltose (linear glucose dimer)
  4. a-limit dextrins (contain a-1,6 branching)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Carb Metabolism: Membrane Digestion (step 2) – function

A

Digest oligosaccharides into monosaccharides

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

Glucose

A

Requires no breakdown to cross lumen –> interstitial space

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

Luminal hydrolysis

A

Protein to aa to tx lumen –> interstitial space

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

Diasaccharides hydrolyzed at brush boarder from oilgomers to monomers

A

Sucrose –> glucose + fructose for transport

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

Example of luminal hydrolysis followed by intracellular resynthesis

A

Triacylglycerol –> glycerol/FA–> cross brush border –> re-essemble TAG–> cross to interstitial

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

Carb Metabolism: Membrane Digestion (step 2) – location

A

Enzymes are integral membrane proteins bound to apical membrane of intestinal epithelial cells

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

Lactose

A

Enzyme: Lactase
Transport: SGLT1
Monomers: Glucose + Galactose

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

Maltose

A

Enzyme: Glucoamylase (maltase)
Transport: SGLT1
Monomers: Glucoses

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

Sucrose & Maltose

A

Enzyme: Sucarase (Sucrose –>glucose+fructose)-isomaltase (maltose –> glucose)
Transport: SGLT1 & GLUT5
Monomers: Glucose + Fructose (sucrose) & Glucose + Glucose (maltose)

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

Salivary gland
-Product
-Substrate
-Stimulator

A
  1. Salivary a-amylase
  2. Starch (amylose & amylopectin)
  3. Food stimuli (PNS)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Pancreas Acinar cells
-Product
-Substrate
-Stimulator

A
  1. Pancreatic a-amylase
  2. Starch (amylose & amylopectin)
  3. Choleocystokinin (CCK) –> stim a-amuylase secreation (acinar cells)
25
SGLT1
Na+ coupled transporter Mediates: uptake of GLUCOSE & GALACTOSE (lumen->enterocyte) Secondary active tx
26
GLUT5
Mediates FACILITATED diffusion of FRUCTOSE into enterocyte
27
GLUT2
Mediates the FACILITATED diffusion of GLUCOSE, FRUCTOSE, GALACTOSE Basolateral --> interstitial space (circulation)
28
Impacts glucose in plasma & H2 in the breath
Lactase deficiency
29
3 ways to digest proteins
1. Luminal peptidases 2. Brush boarder peptidases 3. Cytosolic peptidases
30
Pancreas secretes 5 proteases as proenzyme (activate in small intestine work at slightly alkaline pH)
Endopeptidases: TRYPSIN, CHYMOTRYPSIN, ELASTASE Exopeptidases: CARBOXYPEPTIDASE A & B
31
3 endopeptidases (trypsin, chymotrpysin, elastase)
Disassemble proteins into oligopeptides (<6 aa)
32
Exopeptidases (carboxypeptidase A & B)
Cleave off single aa from oligopeptides
33
Proteases also xxxx --> leads to rapid decrease in luminal activity once enzymes are active
DIGEST EACH OTHER
34
Luminal peptidases
Secreted by stomach (pepsin) and pancreas (tyrpsin, chymotrypsin, carbozypeptidases) Break proteins into smaller oligopeptides in lumen of stomach/small intestine
35
Brush border peptidases
Located apical membrane enterocytes Hydrolyze oligopeptides into aa and di/tripeptides for absorption
36
Cytosolic peptidases
INSIDE enterocytes Further hydrolyze absorbed dipeptides and tripeptides into aa -- transported into bloodstream
37
Trypsin
Pancreatic protease Secreted as trypsinogen Activates other zymogens Digests proteins to peptides and aa
38
Chymotrypsin
Pancreatic protease Secreted as chymotrypsinogen Cleaves aromatic aa within peptide chain
39
Carboxypeptidase A
Pancreatic protease Secreted as procarboxypeptidase A Cleaves hydrophobic aa from the C-terminus
40
Carboxypeptidase B
Pancreatic protease Secreted as procarboxypeptidase B Cleaves basic aa (lysine, arginine) C-terminus
41
Apical absorption enterocyte 1. Dipeptides, tripeptides, tetrapeptides 2. AA
1. Occurs w/ H+ driven transporter 2. occurs with Na+-AA co-transporter
42
Lipase
Triglyceride --> monoglyceride + Fatty Acid
43
Cholesterol ester hydrolase
Cholesterol ester --> Cholesterol + Fatty Acid
44
Phospholipase A2
Phospholipid --> Lysolecithin + Fatty Acid
45
Triacylglycerol (TAGs) Most of lipids in diet
3 Fatty Acids to a glycerol backbone
46
Other lipids in diet (not TAGs)
Phospholipids Cholesterols Free Fatty Acids
47
Lingual Lipase
Not a sig role Stim: fat in food -- sent to stomach Produce: Fatty Acid & Diacylglycerols (DAG) Can't break long chain fatty acids
48
Gastric Lipase
Produced by chief cells Stim: Gastrin from G cells Resistant to PEPSIN in acidic environment Produce: Fatty Acid & Diacylglycerols (DAG) Can't break long chain fatty acids
49
Long Chain Fatty Acids
Require emulsification by bile salts in small intestine Further breakdown by pancreatic lipase
50
Fat digestion
Initiated in stomach Completed in duodenum/jejunum
51
CCK (Cholecystokinin)
Release in response to FA enter duodenum Stim: bile release and pancreatic enzymes
52
GIP (gastric inhibitory polypeptide)
Released by duodenal mucosa in response to FA Helps regulate gastric emptying
53
Pancreatic lipase
MAJOR enzyme for TAG digestion in small intestine requires colipase (cofactor for pancreatic lipase) Hydrolyzes TAGs into monoacylglycerols (MAGs x2), free fatty acids (FFAs)
54
Bile Salts
Emulsify fat droplets -- increase surface area for enzyme activity Facilitate the formation of micelles (transport digestion products MAGs/FFAs/Cholesterol/fat-soluble vita) to brush border --> absorb Recycled via enterohepatic circulation (REUSE)
55
Micelles
Diffuse through water layer @ intestinal brush border --> efficient lipid absorption enterocytes Lipid components absorbed by specific transporters
56
Short chain FA (SCFA) Med chain FA (MCFA)
Diffuse across intestinal epithelium and enter the portal circulation
57
Long chain FA (LCFA) MAGs Lysophospholipids Cholesterols
Re-esterified, incorporated into chylomicrons and exocytosed Chylomicrons so large can ONLY access lymphatic vessels
58
Absorption of Vitamin B12 (cobalamin)
Stomach: B12 binds to heptocorrin Small intestine: binds to intrinsic factor (IF) ---> absorbed endocytosis by enterocytes in ILEUM
59
Vitamin B12
Required for conversion of homocysteine-->methionine

GEMS (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions