Section 5 Flashcards
What are the 5 body composition models?
Atomic, Molecular, Cellular, Tissue, Whole Body
Atomic level
95% - O, N, C, H
4.5% - Na, K, P, Cl, Ca, Mg, S
Molecular level
Water, lipids, protein, minerals (small weight of CHO)
Cellular level
Cells and extracellular fluids and solids
What is cell mass?
intracellular fluids/solids
Tissue level
skeletal muscle, organs, bones, adipose, and residual
Whole body level
size, shape, physique
Two-component model
Body weight = FFM + FM
traditional
What is FFM?
water, protein, mineral (anything that is not adipose tissue)
Three-component model
Body weight = TBW + FFDM + FM
use today
What is the largest component of weight / can measure?
Total body water
What is FFDM?
protein, glycogen, bone/soft tissue mineral
Four component model
Body weight = TBW + BM + FM + residual
Fat mass has a negative or positive influence on activity/performance?
negative
90% non essential lipids
triglycerides for energy
10% essential lipids
omega-3 and omega-6 fatty acids
Why are the essential lipids important?
cell function, inflammatory, mood, behaviour
What does densitometry measure?
body density (mass/volume)
What is denser, water or fat?
water
What is hydrostatic weighing?
weight in air - weight underwater = body density
What does hydrometry measure?
Total body water (estimation of FFM)
% water composition in body
55-65%
What method uses an isotope tracer of a known amount and calculated the known volume/mass?
Isotope Dilution Method (measures TBW)
What does measuring the potassium concentration estimate?
FFM
DEXA
measures bone mineral/fat-free soft tissue
Low radiation exposure method
DEXA
What does BIA measure? (bioelectrical impedance analysis)
measurement of the body’s impedance to the flow of an electrical current from source to sink electrodes (ankle to wrist)
Low impedance
FFM
High impedance
FM
How to calculate FM
FM= BW-FFM
Does body density increase or decrease in boys age 8/10?
decrease
What happens to body density for boys at ages 16/17?
Linear increase
What happens to girls body density at ages 8/11?
decreases
True or false:
At age 14, body density for girls slightly increases then plateaus
true
Do girls have a higher body fat percentage than boys?
yes
During adolescence, which gender has the higher spurt in TBW?
boys
What are the two components of body composition?
FM and FFM
What is absolute fat mass
kg
Who has higher fat mass after age 8?
girls
What is relative fat mass
%
True or false:
Boys have a greater % body fat than girls
false
Describe apidogenesis
Adiphoblasts—–> preadipocytes——-> very small adipocytes—-> mature adipocytes
Adipose cells
- clustered in fat droplets
- many cells supported by collagen
- abundant network of neural connection and blood vessels
Blood bourne hormones/homeostasis
endocrine
Effect local (adjacent cells)
paracrine
Effect secreting cell
autocrine
What important molecules do adipose cells secrete?
Lipoprotein lipase (enzyme), leptin (hormone), IGF-1, PAI-1, angiotensinogen
Function of lipoprotein lipase
- regulation of lipid storage into adipose cells
- hydrolyzes fatty acids for storage
- primary release from subcutaneous adipocytes
- regulation of energy intake/expenditure, glucose/lipid metabolism, puberty, reproductive function, angiogenesis
leptin hormone
Which secretory molecule promotes growth?
Insulinlike growth factor-1 (IGF-1)
Having a high PAI-1 contributes to what?
higher blood clotting and obesity
What is the role of angiotensinogen?
blood pressure regulation
Does a white adipose cell have a large vacuole?
yes
White or brown adipose cell?
- numerous lipid droplets
brown adipose cell
Which adipose cell is larger?
white
Which adipose cell do we have more in the body?
white
Which adipose tissue:
- primarily triglyceride
- well innervated/vascular
- insulation of internal organs
- subcutaneous
- can be measured using skin folds
white
How many adipocytes does a newborn have?
5 billion adipocytes (white adipose tissue)
- 0.5 kg
White adipose tissue postnatally
- 30 to 50 billion in non-obese young adult
- grow in size
- 10 kg (males) to 14 kg (females)
Describe hyperplasia growth in white adipose tissue
increases (doubles) during puberty
Describe hypertrophy in white adipose tissue
- 2 to 3 fold increase in first postnatal year
- no significant increase throughout childhood
- small increase during puberty
True or false:
Breastfed babies are less likely to become obese children
true
Which adipose tissue?
- generation of heat (non-shivering thermogenesis)
brown
Is lipoprotein lipase autocrine or endocrine?
autocrine
Is IGF-1 autocrine or endocrine?
endocrine
True or false:
Extremity fat > trunk fat
true