Nutrient Digestion II - Fats, Vitamins and Minerals Flashcards

1
Q

In what form is almost all fat ingested as?

A

Triacylglycerides

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

What molecule is responsible for fat digestion in the small intestine?

A

Pancreatic lipases

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

How do TAGs present in water?

A

Large lipid droplets

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

Digestion can only take place at what point on a lipid droplet? What implication does this have on speed of digestion?

A

The surface (interface) therefore digests very slowly

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

What process helps to speed up digestion and uptake of lipids from small intestine?

A

Emulsification

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

What two steps occur in the emulsification process?

A

Mechanical disruption and emulsification

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

How is mechanical disruption of lipid droplets achieved?

A

Smooth muscle contraction grinds and mixes lumenal contents

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

What emulsifier is used to break up lipid droplets?

A

Bile (mixture of bile salts and phospholipids)

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

What is an amphipathic molecule?

A

A molecule with both polar and non-polar regions

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

The formation of smaller conglomerate molecules also help speed up monoglyceride digestion. What are these molecules called?

A

Micelles

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

What are micelles comprised of?

A

Monoglycerides
Bile salts
Phospholipids
Fatty acid

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

After crossing into the intestinal epithelial cells, what is the fate of free fatty acids?

A

They are reformed into TAGs in the smooth endoplasmic reticulum and covered in amphipathic proteins

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

What organelle facilitates the transport of TAGs in the epithelial cells?

A

Golgi Apparatus

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

What are extracellular fat droplets called after they have been absorbed?

A

Chylomicrons

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

What are chylomicrons comprised of?

A

Phospholipids, cholesterol, fat soluble vitamins

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

Approximately how large a diameter are chylomicrons?

A

Approx. 1 micron in diameter

17
Q

How do chylomicrons move between epithelial cells and the blood?

A

Through lacteals (lymphatic vessels in the small intestine)

18
Q

How many classes of vitamins are there? What are they?

A

Two:

Fat-soluble
Water-soluble

19
Q

What are examples of fat-soluble vitamins?

A

A D E K

20
Q

What are examples of water-soluble vitamins?

A

B C and folic acid

21
Q

Describe the structure of vitamin B12?

A

Large, charged molecule

22
Q

What happens when someone has a deficiency of vitamin B12?

A

Pernicious anaemia

23
Q

What is pernicious anaemia?

A

Failure of RBCs to maturate

24
Q

How are fat soluble vitamins digested?

A

Follow same pathway as fat

25
Q

How are water-soluble vitamins digested?

A

Binds to intrinsic factor in the stomach and absorbed by specific mechanism in the distal ileum

26
Q

What percentage of daily ingested iron is absorbed into the blood?

A

10%

27
Q

How is iron transported across the brush boarder? Where is it absorbed to?

A

DMT1 into duodenal enterocytes

28
Q

Once inside duodenal enterocytes, how are iron ions stored?

A

In ferritin complex

29
Q

Where is unbound iron found?

A

Across the serosal membrane and into the blood

30
Q

What form does iron in the blood take?

A

Transferrin

31
Q

How is ferritin expression regulated?

A

Based on the body’s iron status

Hyperaemia leads to increased expression (more iron bound in enterocytes)

Anaemia leads to decreased expression (more iron released to blood)