Brainscape's Knowledge GenomeTM

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


See full index

HUBS 192 > Gastrointestinal system 7 > Flashcards

Gastrointestinal system 7 Flashcards

1
Q

What are the main nutrients that undergo chemical digestion

A

Carbohydrates (sugars)
Proteins
Lipids (fats)

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

Why are carbohydrates an important source of energy

A

250-800 mg per day

Storage polysaccharides

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

Describe structure of carbohydrates

A

Large complex chains of monosaccharides - (like glucose)

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

Describe the composition of starch and glycogen

A

Long chains of glucose joined by alpha 1-4 glycosidic bonds

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

What are three disaccharides

A

Sucrose (glucose and fructose)
Lactose (glucose and galactose)
Maltose (2 glucose)

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

How much protein do we ingest a day

A

70-100g per day

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

Are proteins a source of energy

A

No

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

Why are proteins important

A

Required for amino acids

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

How many amino acids can we synthesise

A

12

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

What essential amino acids need to be ingested

A

Histidine
Leucine
Lysine

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

Where do our proteins come from

A

50% diet

50% endogenous proteins - secreted into intestine (enzymes and immunoglobins)

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

How much lipids do we ingest

A

100-150 per day

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

Why do we need lipids

A

Source of energy - not essential -
Fat soluble vitamins (A,D, E & K),
Slow gastric emptying

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

What is the main lipid

A

Gylcerol (backbone with 3 fatty acids attached)

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

What are the viable lengths of fatty acids

A

Short chain - <6 carbons
Medium chain - 6-12 carbons
Long chain - 12-24 carbons

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

Why do we need chemical digestion

A

Large complex molecules only absorbed as small molecules - reduces size of nutrients to allow absorption

17
Q

How is chemical and mechanical digestion related

A

Chemical digestion breaks up food particles to increase surface area for chemical digestion

18
Q

What are general properties of digestive enzymes

A

Extracellular
Organic catalysts
Very specific
Have optimal pH

19
Q

What is the composition of cellulose

A

Long chains of beta 1-4 glycosidic bonds

20
Q

What are the optimal pH’s of different enzymes

A

Salivary enzymes - alkaline
Gastric enzymes - Acidic
Small intestine - Alkaline

21
Q

What are the two stages of chemical digestion called

A

Luminal digestion

Contact digestion

22
Q

Describe luminal digestion

A

Enzymes secreted in lumen
Salivary - amylase
Stomach - pepsin
SI - Pancreatic enzymes

23
Q

Describe Contact digestion

A

In SI - completes digestion before absorption

Involves enzymes produced by enterocytes - attached to brush boarder

24
Q

Describe luminal digestion of carbohydrates

A

Salivary and pancreatic amylase converts polysaccharides to disaccharides

25
Q

Describe contact digestion of carbohydrates

A

Disaccharides converted to monosaccharides - Sucrase, lactase, maltase

26
Q

Describe luminal digestion of proteins

A

Pepsin in stomach

trypsin, Chymotrypsin and carbopeptidase in SI convert proteins into polypeptides

27
Q

Describe contact digestion of proteins

A

Peptidase attaches to brush boarder and converts polypeptides into amino acids

28
Q

Describe chemical digestion of lipids

A

Pancreatic lipase - lingual lipase and gastric lipase minor

No contact digestion

29
Q

What is the problem with lipid digestion

A

Digestive enzymes dissolved in luminal fluid - as lipids are fat soluble requires more complex process

30
Q

Describe the steps in chemical digestion of fats

A

Emulsification
Stabilisation
Digestion (Hydrolysis)
Formation of micelles

31
Q

What does emulsification do

A

Breaks up lipid droplets into small droplets (0.5 - 1 um)
In stomach - simple
In SI - complex - bile salts stabilise

32
Q

Describe Stabilization

A

In SI

Bile salts - released with arrival of food - stabilize emulsion in small intestine - reduces size further

33
Q

Describe bile salts

A

Secreted by liver and concentrated in gall bladder

Have a hydrophobic and hydrophilic side

34
Q

Describe hydrolysis

A

Surface area of emulsion droplets in SI

Lipase converts triglycerides to monoglycerides and free fatty acids

35
Q

What is involved in hydrolysis

A

Involves Lipase and cofactor colipase - secreted by pancreas

Colipase anchors lipase to surface of droplet

36
Q

Why do we need micelles

A

Products of fat digestion insoluble in water

37
Q

Describe formation of micelles

A

Small droplets consisting of 20-30 molecules - Bile salts (amphipathic) surround fatty acids and monoglycerides

HUBS 192 (36 decks)

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