FINAL Flashcards
Describe the main components of human energy expenditure (HEE)
How the Body USes Energy:
- Inhalation of O2 & exhalation of CO2
- Cellular metabolism, disease states, exercise/activity
- Increase in LBM= Increase in EE
Total EE= Heat produced + Work on environment
- Adaptive Thermogenesis (heat production)
- Variable, regulated by brain
- Responds to diet and temperature
- Occurs in brown adipocytes, mitochondria, skeletal muscle, etc.
- When organisms are at rest- all EE is = to thermogenesis - Physical activity (variable)
- Obligatory Energy Expenditure - Required for performance of cellular and organ functions
Understand the cellular processes of HEE
Food + O2 –> CO2 + H2O + Heat
- O2 metabolizes energy received from food
- heat is main product of HEE
- phosphorylation of ADP using oxidation-reduction reactions to produce ATP in Ocidative phosphorylation which requires O2 and produces CO2
Explain the Primary factors that influence HEE
- Key Regulation of ATP Synthesis
- Amount of available ATP(d)
- Ratio of NADH/NAD(i)
- Ratio of FADH/FAD(i)
- Available Oxygen(i)
- Vitamins(i) - Control of ATP Synthesis
- ETC exports H–> Electron Gradient–> ATP Synthase - Uncoupling Proteins
- Creates “leaks” in the ETC
- Allows H+ ions to dissipate across membrane
- Decrease electron gradient
- Decrease capacity to produce ATP
- Generate heat w/o increased energy need
- Uncouples heat production from Oxidative Phosphorylation - Uncoupling of Oxidative Phosphorylation
- e- flow down ETC is coupled to ATP synthesis
- Cyanide and Carbon Monoxide inhibit electron flow
Uncouplers: compounds and systems that result in e- flow with no ATP synthesis (just heat production)
- Proton ionohpores: dinitrophenol, CCCP, FCCP
- Complex 1 inhibitors: rotenone, amytal
- Uncoupling proteins
UNcoupling Protein and Brown Adipose Tissue
- Primarily present in babies & hibernating animals. Human adults primarily have white adipose tissue
-UCP 1: thermogenin- Brown Adipose Tissue
Unidentified (mitochondrial) Carrier Proteins (not uncouplers) - UCP2: muscle
- UCP3: muscle, brown adipose tissue
- Possibly UCP4 and UCP5
Methods to Estimate TEE and EEPA
- Direct Calorimetry or Indirect Calorimetry
- Stable Isotopes
- Activity Monitor
Direct Calorimetry
- Measure of heat production
- Direct measure of energy expenditure
- Required a closed circuit (e.g., a room)
- Subject must live in calorimeter 23 hr/day
Indirect Calorimetry
Measure of CO2 exhalation
Stable Isotopes (names, pros, cons, how)
- Deuterium D2O
- Oxygen-18, H2O^18
Pros: Safe, nontoxic use in from children to elderly, generally portable
Cons: Expensive (generally used for water and analyses)
Use of doubly labeled water:
- Assessment of total, free-living energy expenditure
- estimate body composition
- estimate of daily physical activity, only when combined w/ estimate of RMR using predictions or indirect calorimetry
Prediction equations
- measure a large # of people
- create an equation to match their mean measurements
Activity Monitor
- Pedometer/Accelerometers
Use prediction equation to estimate TEE based on gender, weight, and sometimes age - Use movement coupled with BMR prediction to estimate TEE
Pro: cheap and good for large studies
Con: generally not reliable (+/0 10-20%); weight is measured–> estimation of 70% LBM based on average sex–> significant overestimation of BMR for those with high fat mass
***Activity monitors aren’t accurate–> only to be used for relative data
Statistical Significance:
results are either truth or chance, no result is ever known to be truth
______ _______ is dependent upon cells that produce ATP
Energy metabolism
ATP is formed through ______ _________ requiring O2 and producing CO2
oxidation phosphorylation
The _____ ______ of the ETC is necessary to phosphorylate ADP
hydrogen gradient
