Brainscape's Knowledge GenomeTM

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


See full index

GASTROINTESTINAL PHYSIOLOGY > Digestion of Fats, vits, mins > Flashcards

Digestion of Fats, vits, mins Flashcards

1
Q

How is the majority of water absorbed in the GIT?

A

Passive diffusion through the tight junction following the osmotic Na gdt

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

What does lipase act on?

A

The outside of a lipid droplet

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

How can lipase be made more efficient?

A

Reducing the size of lipid droplets

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

What is the effect of pancreatic lipase on TAGs?

A

TAG -> monoglyceride + 2 FAs

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

Is lipase water or fat soluble?

A

Water soluble

would be useless if soluble in fat

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

What is emulsification?

A

Large water droplets divided into smaller droplets (1mm) increasing its surface area

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

What are the requirements of emulsification?

A

Mechanical disruption

Emulsifying agent

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

How does mechanical disruption occur for gastric emulsification?

A

Smooth muscle contraction grinding/mixing lumenal contents

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

What are the emulsifying agents present in the gastric secretions?

A

Bile Salts

Phospholipids

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

What is the charge of emulsifying agents?

A

Amphiphatic (polar and non-polar portions)

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

What is the orientation of amphiphatic poles in fat droplets?

A

Non-polar side in the fat phase, polar in the water phase (makes it soluble)

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

What is the function of micelles?

A

Speed up the fat digestion process moreso that small droplets of fat
Carry FAs to the brush border membrane

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

How is the reformation of large fat droplets prevented?

A

Polar portions of the amphiphatic molecules repel the polar portions on others

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

Is the micelle absorbed?

A

No - the micelle is just a transportER

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

What are the components of a micelle?

A

Bile Salt
Phospholipids
Monoglycerides
Fatty acids

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

What is the effect of the acidic microclimate on micelles?

A

The FAs become proteinated, destabilising the micelle causing it to release them for diffusion across the membrane

17
Q

Are all FAs/MGs released at once?

A

No, some stored to contantly replenish free molecules

18
Q

Where do FAs/MGs go after entering the cell?

A

Smooth Endoplasmic Reticulum

19
Q

What does the sER do with FAs/MGs?

A

Reform into Triacylglycerols, then covered in an amphiphatic protein (emulsified)

20
Q

What happens with the TAG droplets?

A

Packaged into vesicles on sER membrane, processed by Golgi and exocytosed

21
Q

Where are TAG vesicles exocytosed into the extracellular fluid?

A

Serosal membrane

22
Q

What are extracellular fat droplets called?

A

Chylomicrons

23
Q

What do Chylomicrons contain? How large are they?

A 
TAGs
PPLs
Cholesterol
Fat-soluble vitamins
1um diameter
24
Q

Where are Chylomicrons sent?

A

Passed into lacteals

25
Q

What are lacteals?

A

Small lymphatic branches between endothelial cells

26
Q

What are the fat soluble vitamins?

A

A
D
E
K

27
Q

What are the water soluble vitamins?

A

B group
C
Folic acid

28
Q

How are water soluble vitamins absorbed?

A

Passive diffusion

Carrier mediated transport

29
Q

Why is Vit B12 not passively absorbed?

A

Large charged molecule

30
Q

How is B12 absorbed?

A

Binds to Intrinsic Factor in stomach

Absorbed by transport mechanism in Ileum

31
Q

What is the name given to B12 deficiency?

A 
Pernicious anaemia 
(RBC don't mature)
32
Q

How much iron is absorbed in the intestine?

A

10%

33
Q

What protein is used to transport iron across the brush border membrane?

A

DMT1

Protein coupled

34
Q

Where is iron transported to?

A

Duodenal enterocytes

35
Q

How is iron bound in the cell?

A

Ferritin

36
Q

What happens to unbound iron?

A

Transported across the serosal membrane

Stored as transferrin in the blood

37
Q

What is the ferritin expression in Hyperaemia?

A

Increased ferritin levels, more iron bound in the cells

38
Q

What is the ferritin expression in anaemia?

A

Decreased ferritin levels, less iron bound in cells, more in blood

39
Q

What is the risk of having free iron in the cell/blood?

A

Formation of oxygen free radicals

GASTROINTESTINAL PHYSIOLOGY (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions