FHN- Energy

Anna Regan
Flashcards by Anna Regan, updated more than 1 year ago
Anna Regan
Created by Anna Regan over 5 years ago


FHN exam 14-5-15

Resource summary

Question Answer
Name 3 contributors to energy input Food, Drink, Air, Gut, Skin, Lungs
Name 4 contributors to energy output Faecal loss, urine, other body fluids, air, gut, bladder, skin, lungs.
what is nutritional balance intake = loss
intake > losses = ? Positive balance
Intake < losses = ? Negative balance
Name 4 non-degradable nutrients Energy, iron, nitrogen, calcium, sodium, trace elements.
Name 4 degradable nutrients Protein, fat, carbohydrates, fibre, vitamins.
The time it takes to measure balance is dependent on ______ The nutrient
Name 5 forms of energy Heat, light, electrical, magnetic, kinetic , potential, chemical
heat + kinetic + potential = ? Chemical
When is chemical energy released? When bonds between atoms in nutrient molecules are released.
What are the units of energy? Joules ( J ) Calories ( cal )
1 calorie = ? J 4.184
Approximately how many calories does an average adult use per 24 hours? 1800 - 3000 kcal
What are the atwater values for the macronutrients? Carbohydrate - 4 kcal/g Fat - 9 kcal/g Protein - 4 kcal/g Alcohol - 7 kcal/g
How does a bomb calorimeter work? Food is blended and dehydrated so it can be burnt. Models are used for food and environmental samples. Samples are homogenized and dried.
What is digestible energy (including equation) ? All energy which isn't excreted including body stores. ~ 96% of energy is absorbed. DE = GE - Faecal energy.
What is Metabolizable energy (including equation) ? Energy which is used, not stored. ~84% GE ME = DE (fat) + DE (CHO) + [0.75 x DE (protein)] not all protein is digested - 25% lost in urine.
What is Net Metabolizable Energy? NME = ME - ΔHE
What is Respiratory Quotient and its equation? Oxidation of macronutrients. Ratio of CO2 produced to oxygen used. RQ = CO2/O2
What are the Respiratory Quotients for the macronutrients? Carb - 1.00 Fat - 0.70 Protein - 0.82 Alcohol - 0.67
If a person eats a high fat / low CHO intake will the RQ be high or low? Low
Total Energy Expenditure = ? TEE = Basal metabolic Rate + Dietary induced thermogenesis + energy of physical activity + others.
What is basal metabolic rate? the energy costs of the essential metabolic processes required to maintain life.
What conditions does a person have to be in to measure BMR? lying down, resting (awake), at least 10 hours after last intake, normal body temp, in thermal comfort, without physical/ psychological stress.
What proportion of TEE is BMR? usually 60-70% can be 50-80%
what are the other names for BMR? Why might these be used instead of BMR? Resting metabolic rate (RMR) Resting energy expenditure (REE) Same component but may not be measured under such strict conditions as they are often very difficult to maintain.
What biological components contribute? Heart and respiratory muscle contractions Kidney function Electrical conductivity of nerves Protein synthesis Metabolic processes.
Fill in the table
Put in order of which contribute more - less of % BMR skeletal muscle, adipose tissue, vital organs 1. Vital organs 2. Skeletal muscle 3. Adipose tissue
What influences BMR? body comp, sex, age, disease/ injury, thyroid function.
What is Dietary induced thermogenesis? The increase in energy expenditure observed after nutrient intake
What proportion of TEE is DIT? usually 5- 15%
What are other names for DIT? post-prandial thermogenesis specific dynamic action thermic effect of food/ a meal
What contributes to DIT? Digestion, Absorption, Transport of nutrients, Post-absorptive metabolism, Storage of excess dietary energy.
What influences DIT? Food eaten Time since consumption
If quantity of intake increases will DIT increase or decrease? Increase
If the ratio of CHO : fat increases will DIT increase or decrease? Increase
What is the maximum response time to measure DIT? ~ 1 hour after nutrient intake
What is the definition for physical activity? the increase in energy expenditure observed with physical activity.
What proportion of TEE is PA? Usually 20- 40% Most variable component and depends on the individual
What are other names for PA? thermic effect of exercise thermic effect of activity activity induced thermogenesis
What contributes to PA? Physical movement of the body, heat loss
What influences PA? Activity, Subject
What influences actiivity? Type, intensity, duration, frequency
What influences the subject? Body mass, 'fitness', efficiency
What is the equation for Physical Activity Ratio? energy spent doing activity in x mins/ energy spent in BMR in x mins
Give 3 examples of PAR values 1.0 - 1.4 - lying, standing 1.5 - 1.8 - driving, washing up 1.9 - 2.4 - cooking, mixed housework 2.5 - 3.3 - showering, walking 3-4 km/hr 3.4-4.4 - gardening, walking 4- 6 km/hr 4.5 - 5.9 - dancing, gentle cycling 6.0 - 7.9 - walking uphill, running >8.0 - squash, rock climbing
What are other components of Energy expenditure? non- exercise activity adaptive psychological cold induced drug induced
What is non- exercise activity thermogenesis? include an example NEAT = TEE - ( BMR + DIT + exercise) eg . fidgeting
What are other names for adaptive thermogenesis? non- shivering thermogenesis facultative thermogenesis regulatory thermogenesis
What is adaptive thermogenesis? Activation or suppression of 'futile cycles'
Explain the effect of psychological thermogenesis on energy expenditure. if there is psychological stress energy expenditure increases. It is mediated by stress hormones and can increase heart rate and respiration.
What are the 2 components of Cold-induced thermogenesis? Shivering - rhythmic muscle contractions Non- shivering - adaptive thermogenesis
Give two examples of drugs which contribute to drug induced thermogenesis caffeine, Nicotine
Measuring energy expended as heat = ? Direct Calorimetry
Calculating EE from other measurements that relate to heat production = ? Indirect calorimetry
What are prediction equations? estimate EE from equations based on population measurements
Explain how direct calorimetry is measured subject is placed in an insulated box heat produced by the subject warms the area temperature increase is measured
What are the different types of direct calorimetry? Isothemal heat sink convection differential
Name 3 advantages of direct calorimetry simple in theory direct measurements no conversion factors accurate measurements considered a gold standard
Name 3 disadvantages of direct calorimetry complex to operate in practice expensive equipment equipment rarely available subject is restrained time required for heat equilibration only measures heat produced
What is indirect calorimetry based on? relationship between O2 uptake and CO2 production.
What is collected in indirect calorimetry? inspired and expired air
What are the types of indirect calorimetry? room calorimetry metabolic cart portable respiratory doubly labelled water
Explain what is involved in the room calorimeter/ ventilated chamber sealed well insulated room with bed, chair, table, air lock hatch for food, drink, urine and faeces. air drawn through chamber at measured rate, O2 and CO2 measured entering and leaving, temp and pressure recorded, uptake of O2 and production of CO2 calculated. Then EE calculated using formula.
What are the advantages of the ventilated chamber? accurate can measure TEE over 2-14 days subject less restrained than other methods provides data on nutrient metabolism as well as energy.
What are the disadvantages of the Ventilated chamber? complex to operate in practice expensive bulky equipment subject is not free living time required for gaseous equilibration assumptions must be made in calculations
What is the metabolic cart? Custom- built trolley incorporates O2 and CO2 analyser mouthpiece/mask with tent/ hood software involved used in conjunction with bed or exercise bike.
What are the advantages of the metabolic cart? relatively easy to operate portable accurate enough for clinical/research purposes measure over 0.25- 8 hours health and sick individuals
What are the disadvantages of the metabolic cart? relatively expensive subject is not free living assumptions made in calculations accuracy depends on good calibration
What does portable respiratory require? system to collect inspired/expired air measurement of volume analysis of O2 and CO2 concentration calculation
What are the advantages of portable respirometry? cheap and easy to use can use for physical activities some portable
What are the disadvantages of portable respirometry? poor accuracy rely on assumptions and calculations
What is the technique of doubly labelled water? subject drinks accurate dose of doubly labelled water collect saliva/blood/urine sample for 2-3 weeks plot graph of concentration to show loss calculate rate of loss - CO2 production - energy
What are the advantages of doubly labelled water? measures TEE free living subjects blood sample not essential considered gold standard
What are the disadvantages of doubly labelled water? relies on assumptions isotopes expensive compared with direct calorimetry +/- 7%
Explain the theory behind using a heart rate monitor significant relationship between heart rate and TEE portable, small and non-restraining measurements for 72 hours + best for population studies
What are the advantages of the heart rate monitor? estimates TEE in free living individuals accuracy is ok useful for field studies/ large groups reasonably cheap
What are the disadvantages of the heart rate monitor? if not individually calibrated accuracy is poor not suitable for metabolic studies or accurate research
What are pedometers and accelerometers? portable devices that measure movement
How do pedometers and accelerometers work? attach to body enable collection of free-living date usually require calibration useful for measuring changes useful for groups less useful for quantifying EE
Name the 3 prediction equations for BMR Harris-Benedict 1919 Schofield 1985 Henry 2005
What are the advantages of prediction equations? Cheap quick and easy equipment readily available useful for a rough indicator can be used to check other methods
What are the disadvantages of Prediction equations? Only predict REE inaccurate must be population specific less accurate with individuals least accurate in illness and disease
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