Unit 4: Body Composition & Adipose Tissue Flashcards
What are the different body composition models
Level 1 Atomic, level 2 molecular, level 3 cellular, level 4 tissue, level 5 whole body
Atomic body composition model
Includes oxygen, carbon, hydrogen, nitrogen and other elements
-allows us to break down the body to the atomic level
-95% of our body is O, C, H and N
-4.5% of our body is Na, K, P, Cl, Ca, Mg, S
Molecular body composition model
includes water, protein, minerals, glycogen and lipids
- separates body components into different molecules
-A lot of this work was assessed in the 1900s, via cadaver studies
Cellular body composition model
includes cells, extracellular fluids and solids
-body composition is the sum of all the cells in the body and all the fluids that live extracellularly in the body
- Body composition = cells + extracellular fluids/ solids
-cell mass = intracellular fluids / solids
-Fat mass = sum the total of all adipocytes in the body
-body weight = sum of all the cells
What is body composition made up of on a cellular level
body composition = cells + extracellular fluids / solids
What is cell mass made up of on a cellular level
Cell mass= intracellular fluids / solids
What is fat mass made up of on the cellular level
fat mass = sum the total of all adipocytes in the body
what is body weight comprised of on the cellular level
sum of all the cells
Tissue level body composition model
includes skeletal muscle, visceral, skeleton, adipose and residual
-body composition=sum of the specific issues interested in the study
-body is made up of muscle, adipose, bone, blood, organs and brain
Whole body level body composition model
we can look at the whole-body size, shape, physique
-measure using anthropometry
-body volume and density used to estimate relative body fat
What is the skin comprised of
Hair, epidermis, dermis, subcutaneous tissue
Hair in skin
keeps us warm, protects sensitive areas form dust/ debris
Role of Epidermis
provides a barrier against UV radiation, chemicals, bacteria
Role of Dermis
connective tissue, assist in thermoregulation and aids in sensation
Role of subcutaneous tissue
(Fat) insulating the body, cushions the body stores energy
Visceral adipose tissue
organ linings
Adipose tissue in babies and childern
babies lose body heat more easily than adults due to their size and the extra adipose tissue helps regulate body temperature by providing insulation
Changes in subcutaneous tissue as we age
our body fat typically increases until about age 70 but fat distribution changes
-decreases in face, hands and feet
-increases in the thighs and abdomen
10 methods for estimating body composition
Skinfolds, body circumference measurements, dual-energy X-Ray Absorptiometry, hydrostatic weighing, air displacement plethysmography (body pod), Bioelectrical impedance analysis (BIA), bioimpedance spectroscopy (BIs), electrical impedance myography (EIM) 3D body scanners, multi-compartment models
Skinfolds
-has been used to estimate body fat for >50 years
-measure the thickness of your subcutaneous fat
-7-site measurement: axilla, chest, abdominal, subscapular, suprailiac triceps, thigh
Advantages of skinfolds
affordable, measurement can be taken quickly, portable
Disadvantages of skinfolds
method of collecting data requires practice, if done incorrectly can hurt
Body circumference measurements
-uses flexible measuring tape
-shape of your body can provide information about your body fat
-used by the military along with age and height to calculate body fat
-neck, waist and hips
advantages of body circumference measurements
easy, affordable, portable
Disadvantages of body circumference measurements
not considered an ideal method of measuring body fat - doesn’t take into account muscle vs fat
Dual- Energy X-Ray absorptiometry
DXA uses X-rays of 2 different energies to estimate your body fat percentage
-one low energy and one high
- Patient lies on back for 10-minutes, W-ray scans over them
DXA advantages
provides accurate and detailed information including a breakdown of different body regions and body density readings
DXA disadvantages
does not take into account muscle vs fat
Hydrostatic weighting
(underwater weighing)
- relies on densitometry
-density=mass/ unit volume
-water =1.0gm/cm^3
-fat= 0.9007 gm/cm^3
-lean = 1.100 gm/cm^3
Disadvantages of hydrostatic weighting
under water weight is quite a low number compared to out of water weight
not ideal for childern under 7 or individuals who are uncomfortable with being submerged under water
Bod Pod
a computer-based egg shape device that measures your weight and volume to determine your body density and calculate your percentage of body fat
-sit inside bod pod for about 3 minutes
-pressure changes feel similar to airplane or elevator
What information does the bod pod provide
% fat, %fat free mass, fat mass, fat free mass, body fat rating
Bioelectrical Impedance analysis (BIA)
makes an estimation of body composition
-runs a small electrical current through the body
-uses resistance of the body
-dehydration, consuming meals and exercise are recognized factors affecting BIA results (about +/- 5 kg)
-current moves slower through fat
- measures total body water
Bioimpedance spectroscopy (BIS)
Non-invasive, passes low strength, painless electrical currents through the body measuring the flow of the current
-measures body’s resistance to currents
-uses a multiple frequencies
BIS is able to not only measure total body water but can differentiate between extracellular water and intracellular water
-can estimate body cell mass
Electrical Impedance Myography (EIM)
an electrical current is applied to a muscle or specific muscle group of interest
-more localized approach
-mostly used in examining muscle
3D Body scanners
uses multiple infrared depth sensors
-multiple applications for these machines (airport security, fitness)
-very expensive
Multicomponent models
Partition of body mass into meaningful components
Two-component model (traditional)
Three- component model
Two-component model
body weight = fat free mass + fat mass
three-component model
Body weight = total body water + fat free dry mass +fat mass
-TBW - largest component of weight
-FFDM - protein, glycogen, bone, soft tissue, minerals
Why is it important to use the same brands throughout research experiments
slight differences between brands
Changes in body density through growth
-not much of a sex difference in early childhood
-we have more info on body density at around 8-10 (hydrostatic weighing hard on children)
-slight increase after 12
-plateau around 14 in girls
-boys have higher body density than girls but have less fat %
Do boys tend to increase or decrease in their percent of body fat
decrease
Stages of adipogenesis
Adiphoblasts, preadipocytes, very small adipocytes, mature adipocytes
Adipogenesis stage 1
Adiophoblasts- embryonic stage for the maturation of adipose tissue celss
Adipogenesis stage 2
Preadipocyte- fat cell precursor
Adipogenesis stage 3
very small adipocytes- very small drops of adipose tissue containing hormones
Adipogenesis stage 4
Mature adipocytes - what we would see after birth
Types of adipocytes
white, beige and brown
White adipocytes
- one fat droplet
-few organelles
-most abundant in adult life
-located under skin and around internal organs as well as in central cavities of bones
-stores energy
-insulates the body, cusions vital organs and secrets body hormones
Beige adipocytes
scattered among white adipocytes, sometimes generate heat
Brown adipocytes
-many fat droplets
-many mitochondria
-generates heat
-more in fetal life and infancy
-upper back, above clavicles and around vertebrae
Divisions of white adipose tissue
Subcutaneous fat: greatest portion, cushions trauma, insulation of the bones and muscles
internal fat: protects the organs (intestines, kidneys and liver)
White adipose tissues during prenatal developement
at 14 weeks gestation white adipose cells are noticeable, after 23 weeks they multiple and this is the rapid weight gain we see in the last trimester of growth
White adipose tissues in newborns
about 5 billion adipocytes and are about 30 to 40 micrometer in diameter
-stored energy for extra-uterine life
-many babies will lose 1 to 2 pounds right after birth because it takes time for the digestive system to become more efficient
White adipose tissue in postnatally
30-50 billion adipocytes in non-obese young adults
-80 to 100 micrometers in diameter
hyperplasia
-no immediate postnatal change
-age 1 to 2 through to middle childhood years we see an increase
-puberty- the number of fat cells doubles
-young adulthood the number of fat cells plateaus
-increase in fat cells is really stimulated with any over consumption of calories - in obese children there may be fat cells increase 8-12x the amounts
What kinds of animals/ stages in human life is there a great amount of brown adipose tissue
animals that hibernate, babies, adult humans only have it in certain regions ( around kidneys, back of neck)
-after infancy brown adipose tissue shrinks and disappears in most areas of the body
Characteristics of brown adipose tissue
higher proportion of mitochondria -allows for production of heat
Brown in color
responsible for non-shivering thermogenesis
How does breast feeding affect obesity
breast fed babies are less likely to become obese children
Trends in Steps per day
Decreases with age, increases with income, decreases with high body max index, decreases with the amount of tv one watches
4 things families can do to prevent childhood obesity according to the CDC
- Model a healthy eating pattern - adopting a healthy eating pattern as a family helps children reach and maintain a healthy weight as they age
- Move more as a family - physically active youth have stronger muscles and bones, better cardiovascular fitness, and lower body fat compared to those that are inactive
- Set consistent sleep routines - Lack of sleep lead to lack of energy throughout the day to be physically active
- Replace screen time with family time- in children, screen time can lead to pour sleep, weight gain, and poor mental health. reducing screen time can free up time for family activities and can remove cues to eat unhealthy food
How long should children ages 3-5 be active for in a day
Should be active throughout the day
How long should children ages 6-17 be active for throughout the day
60 minutes of physical activity a day
How many hours of sleep do children 6-12 need per night
9-12 hours per night
how many hours a night do preschoolers need
11-13 hours per day (including naps)
How many hours of sleep do children ages 13-18 need
8-10 per night
