Brainscape's Knowledge GenomeTM

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


See full index

GI > Nutrition and Digestion (FATS + VITAMINS + MINERALS) > Flashcards

Nutrition and Digestion (FATS + VITAMINS + MINERALS) Flashcards

1
Q

what form does dietary fat usually take

A

triglycerides (triacylglycerol)

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

What form do triglycerides have

A

glycerol backbone with 3 stearic (fatty) acid chains

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

what digests fat in the small intestine

A

pancreatic lipase

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

how do triglycerols present in water

A

large lipid droplets - insoluble in water

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

what kind of enzyme of lipase

A

water soluble - digestion can only take place at the surface of the lipid droplet so very slow

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

emulsification definition

A

dividing large lipid droplets into smaller droplets

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

how does emulsification help with digestion of lipids

A

by making the droplets smaller the surface area on which lipase can act is increased

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

three steps to emulsification

A
  1. mechanical disruption - large droplets to small droplets
  2. smooth muscle contraction grinds and mixes lumens content
  3. emulsifying agents present - prevent small droplets reforming large droplets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how do emulsifying agents work

A

they are amphipathic molecules (i.e. have polar and non-polar portions)

  1. Polar (charged) surfaces so repel each other and stop reaggregation
  2. non-polar portions associate with non-polar interior interior
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

emulsifying agents

A

bile salts and phospholipids secreted in bile

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

Aside from emulsification, what else helps speed up absorption of lipids

A

micelles - similar to emulsion droplets but smaller

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

what makes up a micelle

A

bile salt + monoglycerides + fatty acids + phospholipids

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

where are the polar and non-polar portions of micelles

A

polar - at micelle surface
non-polar - form micelle core
*Micelles never enter cells

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

How do micelles breakdown

A
  1. in low pH layer there is an acid microclimate at cell surface
  2. causes them to take on H ions - become uncharged
  3. small amounts of free fatty acids (FFA) and monoglycerides released into solution
  4. FFA diffuse across the the membrane into the cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

where do fatty acids and monoglycerides go when they enter epithelial cells and what happens there

A

go to the smooth ER

reformed into triacylglycerols (by enzymes in sER)

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

what happens during emulsification of triacylglyceril

A

triacylglycerol coated with amphiphatic proteins

17
Q

what happens after the triacylglycerol droplets have been emulsified

A

transported through cell in vesicles formed from sER membrane - processed through Golgi apparatus and exocytosed into extracellular fluid at serosal membrane

18
Q

what are the extracellular fat droplets known as

A

chylomicrons (also contain phospholipids, cholesterol and fat soluble vitamins)

19
Q

where do chylomicrons pass through

A

pass into lacteals between endothelial cells (cannot pass through capillary basement membrane)

20
Q

what are the 2 classes of vitamins

A

fat soluble

water soluble

21
Q

what are fat soluble vitamins and how are they absorbed

A

A, D, E, K - follow the same absorptive path as fat

22
Q

what are water soluble vitamins and how are they absorbed

A

B group, C, folic acid - either absorbed by passive diffusion or carrier-mediated transport.

23
Q

how is B12 (a large charged molecule) absorbed

A

Binds to intrinsic factor in stomach to form complex which is absorbed via specific transport mechanism in distal ileum

24
Q

what can B12 deficiency lead to

A

pernicious anaemia

failure of red blood cell maturation

25
Q

where and how is iron absorbed into the blood

A

across the intestine - transported across brush border membrane into duodenal enterocytes via DMT1 (divalent metal transporter 1)

26
Q

what happens to iron ions once in the duodenal enterocytes

A

incorporated into ferritin (protein-iron complex  intracellular iron store) - becomes BOUND

27
Q

what happens to unbound iron

A

transported across serosal membrane into blood - here it binds to transferrin

28
Q

what regulates ferritin expression in the body

A

the body’s iron status

29
Q

what does hyperaemia cause

A

increased ferritin levels - more iron bound in enterocytes

30
Q

what does anaemia cause

A

decreased ferritin levels - more iron released to blood

31
Q

when iron reacts with oxygen what is formed

A

free radicals which are bad for the body

32
Q

how does the body get around the formation of free radicals

A

reduces them from Fe3+ to Fe2+

Fe2+ is held in ferritin - prevents it from reacting with oxygen - once in it cannot get out

33
Q

what happens to faeces if there is more iron in them

A

get much darker

GI (25 decks)

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