Brainscape's Knowledge GenomeTM

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


See full index

YEAR 2: Skeletal Muscle in Health and Disease (MGEM2017 UNUK) (SPR1 23-24) > Whole body Composition: Measurement Methods > Flashcards

Whole body Composition: Measurement Methods Flashcards

1
Q

what is a limitation of body composition in vivo?

A
  • all in vivo methods for whole body composiiton are estimations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are 4 reasons we use body composition analysis?

A
  • tracks epidemiological differences and changes
  • determine the true efficacy of interventions
  • assess health risk
  • determine the cause of weight change (e.g in sarcopenia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the three components of body composition

A
  • bone
  • fat
  • muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the benefits of skin fold measurements?

A
  • cheap
  • easy to use
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what percentage of muscle is water?

A

75%

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

what percentage of fat is water?

A

10%

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

what is component of the body carries the highest percentage of body weight and give its percentage

A
  • muscle
  • 41% of body weight
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

why do females generally have 4 times greater essential fat than males?

A

for child-bearing and pregnancy

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

how much body fat does the average young male possess vs females in percentage?

A

males:
- 12-15%

females:
- 25-28%

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

what can testosterone do other than increase muscle mass?

A

It can help increase fat metabolism

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

what are the percentages of these normal body fat classifications in males AND females:

  • unhealthy range (too low)
  • acceptable range (lower end)
  • acceptable range (higher end)
  • unhealthy (too high)
A

MALES:

  • unhealthy (too low): ≤ 5%
  • acceptable (lower end): 6-15%
  • acceptable (higher end): 16-24%
  • unhealthy (too high): ≥ 25%

FEMALES:

  • unhealthy (too low): ≤ 8%
  • acceptable (lower end): 9-23%
  • acceptable range (higher end): 24-31%
  • unhealthy (too high): ≥ 32%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Density of what is lower in children than in adults?

A

density of free-fat mass is lower

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

what component of free fat mass is higher in children compared to adults?

A

water content of free fat mass is higher in children compared to adults

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

what are 3 reasons why muscle mass important in older age

A
  • decreased muscle mass = increase in injury
  • glucose disposal to prevent high blood glucose levels, which can lead to things like diabetes
  • glycogen storage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

in body composition equations/methods, why are there more components in some equations/methods?

A

because the more components the equation/method uses, the more reliable it is

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

Give 3 examples of 2 component body composition measurment methods

A
  • skinfolds
  • hydrodensitometry
  • BIA (bioelectrical impedence analysis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what 2 things do two component body composition equation methods assume?

A

Assumes that:

  • density of fat is 0.9
  • density of fat-free mass is 1.10 kg/L^-1
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Give an example of a three-component body composition measurment method/equation

A
  • radio-active isotope tracers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what does the three component body composition equation/method overcome and why?

A
  • As it includes an actual measure of body water, it overcomes errors introduced when a constant proportion of 0.72 Free fat mass is assumed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are 2 examples of four component body composition equation methods?

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

what does the four component body composition equation/method overcome and why?

A
  • As the four component body composition method/equation includes an actual measure of body mineral conent, it overcomes errors introduced when a constant proportion of 0.72 Free-fat mass is assumed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the chemical division of two component body composition equations and what is the anatomical division?

A

chemical:
- fat mass (FM) vs ONLY Fat Free Mass (FFM)

Anatomical:
- adipose tissue vs Lean Body Mass (LBM)

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

what are the chemical and anatomical divisions of multi-component body composition equations

A

chemical:
- Fat mass vs Water, protein, mineral, and or carbohydrates

Anatomical:
- adipose tissue vs. muscle, skeleton, skin, viscera

24
Q

what is hydrostatic weighing?

A

a body composition technique based on archimedes principle of water displacement. The loss of weight in water equals weight of water displaced which yields volume of water displaced at any temperature

25
Q

what are the 2 equations for hydrostatic weighing?

A
  1. Weight in air - weight underwater = weight of water displaced
  2. Body volume (BV) = (BW-UWW)/0.997 - (RV+0.1)

where:
- BW = body weight in air
- UWW = under water body weight
- RV = litres of gas in lungs

26
Q

what are 3 advantages hydrostatic weighing

A

Advantages:
- Used to be considered gold standard
- scientifically sound principle for body volume
- no radiation exposure

27
Q

what are 5 limitations of hydrostatic weighing

A

Disadvantages:
- includes measurement of residual lung volume
- Precision of underwater weight
- cost (can be expensive)
- Non-portable
- Not suitable for all subjects

28
Q

what are 2 assumptions of Hydrostatic weighing

A
  • assumes density of fat and lean mass are constant between individuals
  • assumes GI gas volume is constant
29
Q

outline how an air displacement plethysmography works in 2 steps?

A
  1. measures body volume by air displacement by measuring the pressure changes with injection of known volume of air into the closed chamber
  2. the large body volume displaces air volume in chamber resulting in bigger increase in pressure with injection of known volume of air
30
Q

what is the advantage of air displacement Plethysmography?

A
  • high validity compared to hydrodensitometry
31
Q

how does bioelectrical impedance anaylsis measure impedance?

A

measures impedance (opposition) by body tissues to the flow of a small (** < 1mA**), alternating electrical current of 50kHz

32
Q

what 2 things is impedance a function of?

A

function of:
- electrical resistance of tissue
- elecrtrical capacitance (storage) of tissue (reactance)

33
Q

in bioelectrical impedance analysis, what facilitates electrical flow and what doesn’t and why?

A
  • hydrated fat free body tissues and extracellular water facilitate flow.
  • fat does not facilitate flow

this is because of greater electrolyte content of fat-free componenet

34
Q

in bioelectrical impedance what needs to be the same between each test?

A

the hydration levels of the subject

35
Q

what are the 3 advantages of bioelectrical impedance analysis?

A
  • inexpensive
  • portable
  • quick and non-invasive
36
Q

what are 3 limitations of bioelectrical impedance analysis?

A
  • low accuracy precision but no worse than hydrodensitometry
  • variation between manufacturers/models
  • very sensitive to hydration, temp and electrode position
37
Q

what are 3 assumptions made during bioelectrical impedance analysis

A
  • assumes the body is a series of cylindrical units
  • assumes homogeneous body composition
  • assumes a large limb contribution
38
Q

what method is most widely used by COMAP for whole-body composition?

A

Dual-energy X-ray Absorptiometry (DXA)

39
Q

what are 5 limitations of a DXA scan?

A
  • expensive specialist equipment
  • radiation exposure
  • radiation trained staff are required to operate them
  • no reference values for certain groups
  • excludes populations like pregnant women
40
Q

what are 5 advantages of a DXA scan?

A
  • accurate
  • reliable
  • no discomfort for patients
  • 4-compartment/component model
  • can be used to look at regional/local composition
41
Q

what 3 steps explain how a DXA scan works on a basic level

A
  1. 2 different energy-level x-ray are emitted by the DXA scanner
  2. lean mass, fat mass and bone mass each reduce/attenuate the X-ray signals in different ways
  3. computer analyses scan point by point to determine body composition
42
Q

how does ultrasound work?

A

It converts electrical energy through a probe into high frequency pulsed sound waves that penetrate the skin surface to the fat-muscle interface

43
Q

what method of assessment of body composition is most widely used by COMAP for assessment of single muscle architecture?

A

Ultrasound

44
Q

what are 5 measurements that are included in anthropometry?

A
  • skinfolds
  • height
  • weight
  • width
  • circumferences
45
Q

what is a disadvantage of skin-folds regarding Fat?

A

it can only measure subcutaneous fat (fat under the skin) and not visceral fat (around the liver etc)

46
Q

in skinfolds, how much constant tension does the calipers exert?

A

10 g/mm^2

47
Q

what does the sum of skinfolds indicate?

A

relative fatness of the individual

48
Q

what are 4 advantages of skin-folds

A
  • inexpensive
  • quick
  • portable
  • larger reference database
49
Q

what are 3 limitations of skin-folds

A
  • there can be technician error
  • skinfold thickness can be affected by factors other than amount of fat
  • poorly predicts visceral fat
50
Q

use 2 steps to explain how a CT scan works

A
  1. generates detailed cross-sectional, 2 dimensional radiographic images from many x-rays taken at different angles
  2. x-rays will pass through tissues of different densities
51
Q

what 3 things does a CT scan provide quantitive information on?

A

Provides quantitive information on:
- total tissue area
- total fat and muscle area
- thickness and volume of tissues within an organ

52
Q

what is the 2 disadvantages of CT scan?

A
  • high radiation exposure
  • expensive
53
Q

what are the 2 advantages of CT scans

A
  • highly accurate
  • can be diagnostic
54
Q

outline 2 steps of how MRI works

A
  1. electromagnetic radiation (NON-IONSING) in strong magnetic field exites hydrogen nuclei of body’s water and lipid molecules
  2. these nuclei then project detectable signal to visually represent various body tissues
55
Q

what does MRI provide quantitative information on?

A

provides quantitative information on total and subcutaneous adipose tissue

56
Q

3 advantages of MRI

A
  • doesnt use ionising radiation
  • ongoing cost (once the machine is bought) arent extremely expensive
  • provides quantitive infomration on total and subcutaneous adipose tissue
57
Q

1 disadvantage of MRI?

A
  • expensive to initially buy the MRI scanner

YEAR 2: Skeletal Muscle in Health and Disease (MGEM2017 UNUK) (SPR1 23-24) (23 decks)

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