Brainscape's Knowledge GenomeTM

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


See full index

BAMS Human Systems > Macronutrients: digestion and absorption > Flashcards

Macronutrients: digestion and absorption Flashcards

1
Q

what acute and chronic illnesses is a vitamin D deficiency associated with?

A

preeclampsia
childhood dental caries
periodontitis
autoimmune disease
infectious diseases
cardiovascular disease
deadly cancers
type 2 diabetes
neurological disorders

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

what does vitamin D do for the teeth?

A

absorbs, carries and deposits calcium in the bones

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

what does a lack of vitamin D lead to in the teeth?

A

dental caries
weak and brittle teeth that easily break chip and crack

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

what is the % reduction of cavities in children that take vitamin D supplements?

A

47%

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

what are the primary reasons for nutrient imbalances?

A

inadequate intake, malabsorption and nutrient wasting

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

what medical conditions can a nutrient imbalance result in?

A

chrons disease
cystic fibrosis
bariatric surgery
parental and tube feeding
allergic states
HIV infection
malignancies

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

what are renal and hepatic diseases and what do they lead to?

A

Alter protein storage and lead to nutritional deficiency

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

what social factors contribute to insufficient nutritional intake?

A

poverty
homelessness
famine
war

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

what is the difference between free sugar and not free sugar?

A

free sugar = monosaccharides/ disaccharides ADDED to the food or sugar naturally present in honey, syrups and unsweetened fruit juices and fruit juice concentrates
not free sugar = sugar NATURALLY PRESENT in intact fruits and lactose naturally present in human milk, formula, cow/goat milk, unsweetened milk products

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

what type of sugar increases the risk of obesity, diabetes, poor nutrient supply and dental caries?

A

free sugars

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

what do non starch polysaccharides do in the GIT?

A

absorb water > faecal bulking > increases transit time

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

what are NSPs fuel for?

A

bacterial metabolism

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

what are 3 common characteristics of dietary fibre?

A
  • saccharides of plant origin
  • resistance to digestion and absorption in the small intestine
  • fermentation in the colon to produce short chain of fatty acids that are absorbed and metabolised in various pars of the body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what short chain fatty acids are produced from the fermentation of NSPs?

A

acetic acid
propionic acids
butyric acid

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

what are oligosaccharides?

A

non digestible polysaccharides
dietary fibre

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

what are fructans?

A

inulin and oligofructose
(mix of oligosaccharides and polysaccharides composed of fructose)

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

inulin and oligofructose are not hydrolysed or absorbed in the upper GIT. what happens to them?

A

reach colon and become either totally, patially or not fermented.

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

what ferments inulin and oligofructose in the colon?

A

microflora

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

what does the fermentation of inulin and oligofructose in the colon lead to?

A

selective simulation of the growth go the bifidobacteria population

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

why are inulin and oligofructose termed prebiotics?

A

nondigestible good ingredients that selectively stimulate growth and activity of a number of potentially health stimulating intestinal bacteria

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

name 3 natural sources of inulin and oligofructose?

A

chicory roots
Jerusalem artichokes
garlic

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

what is the recommended daily intake of dietary fibres in most countries (not western)?

A

25-35g

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

what is hydrolysis in terms of carb digestion?

A
  • basic process of digestion
  • major types of macronutrients in food are primarily digested by hydrolysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what must happen to polysaccharides and disaccharides prior to them being absorbed?

A

they must be digested to monosaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

describe the digestion process of starch?

A

first digested by amylase in pancreatic secretions (and saliva) to maltose, maltriose and limit dextrins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

disaccharides require brush border hydrolyses. what are these?

A

maltose - cleaves maltose unto 2 molecules of glucose
lactase - cleaves lactose into a glucose and a galactose
sucrase - cleaves sucrose into a glucose and a fructose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what happens to polysaccharides in the GIT?

A
  • starches digested to maltose and glucose units, absorbed as glucose in SI
  • NSP digested in LI and absorbed as SCFA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what happens to oligosaccharides in the GIT?

A

digested in LI and absorbed as SCFA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what happens to mono and disaccharides in the GIT?

A

digested and absorbed in small intestine as monosaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

do monosaccharides eg. glucose and fructose in fruits need to be digested?

A

no they are absorbable carbohydrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is a lactose intolerance?

A

loss of lactase at weaning
- lactose not hydrolysed, passes to bowel and metabolised to SCFA, gases

32
Q

how do you diagnose a lactose intolerance ?

A

H2 in breath for lactose malabsorption

33
Q

what is a secondary lactose intolerance?

A

infection, illness - reduced lactase expression

34
Q

what are GLUT transporters?

A
  • all facilitated (passive transporters)
  • 12 members
35
Q

what are SGLT (sodium glucose transport) transporters?

A
  • active transporters that need sodium
  • move glucose from low to high conc
36
Q

how are sugar transported regulated?

A

dietary CHO bioavailability

37
Q

what is the transport capacity of human intestines?

A

10kg of monosaccharides per day

38
Q

what are the metabolic and hormonal responses after meal intake?

A
  • increases blood glucose
  • intakes blood TG
  • decreases blood NEFA
  • decreases B-hydroxybutryrate
  • increase insulin
    *decreases glucagon
39
Q

what is the fate of dietary carbohydrates?

A
  • glucose uptake by muscles
  • liver and muscle glycogen synthesis
  • oxidative disposal of glucose in muscle and other tissues
40
Q

what is the definition of fats?

A

solid at room temp
- refers to dietary triacylglycerols (triglycerides)

41
Q

what is the definition of oil?

A

liquid at room temp

42
Q

what is the definition of lipid?

A

group of water insoluble compounds of which trycylglycerols are the major form in diet

43
Q

what are the main dietary lipids?

A
  1. triacylglycerols or triglycerides 90-95%
    = glycerol and 3 fatty acids
  2. phospholipids
    = phosphorus + 2 fatty acids (lecithin)
  3. sterols
    = derived from fatty acids (cholesterol)
44
Q

how do the presence of double bonds structurally effect the properties of fatty acids?

A
  • saturated and unsaturated fatty acids
  • cis and trans isomers
  • position of the double bond
45
Q

what is a saturated fat?

A

no double bonds present so all C atoms are fully saturated with H atoms

46
Q

what are the 2 types of unsaturated fat?

A

monounsaturated = 1 double bond
eg. olive oil, rapeseed oil

polyunsaturated =>1 double bond
eg. sunflower oil

47
Q

what are cis fats?

A

configuration of double bonds in naturally occurring unsaturated fats
eg. veg oil

48
Q

what are trans fats?

A

have 1 double bond
- industrially produced - ‘partially or fully hydrogenated’
- naturally occurring - meat/dairy & produced by action of bacteria in stomach

49
Q

what is TAG digestion?

A

emulsification by bile acids and formation of small micelles
hydrolyses of TAG by pancreatic lipase

50
Q

what problems are there with fat digestion?

A

fat is insoluble in water
enzymes in aqueous phase

  • need to bring both together to break up fat
51
Q

what are some emulsifying agents?

A

fatty acids
monoglycerides
cholesterol
lecithin
protein
bile acids

52
Q

what happens during micelle formation?

A

bile acids with fatty acids
- at critical micellar concentration
2-5mmol/l from mixed micelles
- bile acids coat lipid soluble material with water soluble skin

53
Q

what is the structure of a micelle?

A
  • polar head = hydrophilic
  • non polar hydrocarbon tail = hydrophobic
  • hydrophobic lipid core = insoluble long chain fatty acids, 2-monoacylglycerol, tocopherol and carotenoids)
54
Q

how are fatty acids absorbed?

A
  • at brush border - lower pH at mucosa reduces solubility of lipid in micelles
  • fatty acids absorbed by diffusion (but may be a carrier protein)
55
Q

what fatty acids don’t need micelles?

A

medium chain fatty acids

56
Q

when do fatty acids go straight into portal blood?

A

when they are less than 12 carbons long

57
Q

what happens if fatty acids are more than 12 carbons long?

A

triglycerides reformed in cell coating in protein, phospholipid and cholesterol enclosed in vesicles

58
Q

what side are chylomicrons and how are they secreted?

A

76-100nm in diameter
secreted into lymphatics via lacteals

59
Q

what form chylomicrons?

A

newly formed TAG packed with phospholipids and proteins
- dietary cholesterol cholesterol esters also incorporated into the chylomicrons

60
Q

what is the composition of newly secreted chylomicrons?

A

core = TAG, cholesterol esters

surface = unesterified cholesterol, phospholipids, apoproteins B48 and A1

61
Q

how much of our total protein intake is made up of animal protein foods?

A

60-70%

62
Q

how are proteins absorbed?

A

rarely absorbed whole so are digested into amino acids or di and tripeptides

63
Q

what does acid do in the digestion of proteins?

A
  • denatures proteins, unfolding the 3D structure
  • activates zymogen - pepsinogen to pepsin
  • stimulus for proteolytic enzyme secretion
64
Q

what % of proteins are digested by stomach pepsin?

A

20%

65
Q

where are dietary proteins hydrolysed and what do they go into?

A

within the lumen of the small intestine predominantly into medium and small peptides (oligopeptides )

66
Q

what does protein digestion rely on?

A

pancreatic proteases either endopeptidase or exopeptidase

67
Q

what is endopeptidase?

A

a pancreatic protease that acts inside the peptide chain

68
Q

what is exopeptidase?

A

a pancreatic protease that acts at the extremities of the peptide chain

69
Q

give an overview of the 3 steps of protein digestion?

A

proteins to peptides to peptides and amino acids

70
Q

what type of transporters are majority of the ones involved in amino acid absorption?
what do they depend on?

A

sodium dependant co transporters
- only bind amino acids after binding sodium

71
Q

what does amino acid absorption have to do with water absorption?

A

amino acid absorption generates an osmotic gradient that drives water absorption

72
Q

what peptides can be absorbed and which can’t?

A

peptides longer than 4 amino acids will NOT be absorbed
- di and tri peptides are absorbed in the small intestine

73
Q

how are di and tri peptides digested into amino acids?

A

by cytoplasmic peptidases

74
Q

what are the functions of macronutrients?

A
  • provide energy in sufficient quantities
  • provide range of building blocks
  • provide essential nutrients we can’t make ourselves
75
Q

how much energy per gram of the following macronutrients in kcal?

  • carbs
  • fat
  • protein
  • alcohol
A

carbs = 4
fat = 9
protein = 4
alcohol = 7

76
Q

what is the role of essential fatty acids?

A
  • cell membranes
  • biologically active compounds
  • growth and development
77
Q

what is the role of dietary fats?

A
  • energy provision
  • essential fatty acids
  • help carry fat-soluble vitamins
  • enables storage of energy
  • structural role in cell membranes
  • metabolic functions

BAMS Human Systems (33 decks)

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