Peds 200 Energy Transfer 1&2

Front 1

define energy.

Back 1

the capacity to do work.

Front 2

1st law of thermodynamics

Back 2

"in any process, the total energy of the universe remains connstant- principle of conservation of energy" or " energy cannot be created or destroyed but can be transformed from one form to another."

Front 3

metabolism

Back 3

energy transformations within the body that allow mechanical work (e.g. muscle shortening), chemical work (e.g. protein synthesis) or transport work (e.g. active transport).

Front 4

exergonic and endergonic

Back 4

reactions that releases energy and endergonic stores energy.

Front 5

what is the common chemical intermediate?

Back 5

ATP is the common chemical intermediate for the transfer of energy from food or other high energy compounds to cellular processes including muscle contraction.

Front 6

energy transfered in the body includes all the chemical processes involved in the production and utilization of what?

Back 6

ATP Adenosine Triphosphate

Front 7

what is the enzyme that breaks down ATP and where is it structurally bond?

Back 7

ATPase and the head of the myosin.

Front 8

what happens to the energy from food that is not converted to mechanical energy?

Back 8

it is lost as heat energy

Front 9

what is the 2nd Law of Thermodynamics?

Back 9

all processes move toward decay and disintegration, with a net increase in what is the entropy or state or randomness/ disorder within the system. therefore total energy conversion produces some usable energy (mechanical) and some unusable energy (heat)

Front 10

how do we measure heat energy?

Back 10

with a Calorimeter.

Front 11

what is a calorie?

Back 11

the amount of heat needed to raise one gram of water 1'C.

Front 12

what are the limitations to Direct Calorimetry?

Back 12

~expensive
~not all the heat generated in a carlorimeter is from the body
~thermoregulation of a subject influences the rate of heat given off
~ not the most efficient

Front 13

what do we know from using direct calorimetry?

Back 13

the amount of O2 consumed is proportional to the work done and heat given off.

Front 14

explain of we use can use indirect calorimetry.

Back 14

during exercise/rest we consume O2 to enable our metabolic pathways to convert food energy into cellular/mechanical energy resulting in heat energy production and given off CO2. so we can use VO2 (l/min) during exercise to determine total energy expended from muscular work (ergometry) and heat production (calorimetry).

Front 15

how is VO2 and VCO2 measured during open spirometry?

Back 15

we only need to determine the amount of expired O2 &CO2 to be able to calculate consumed O2 and CO2 produced .

VO2 (concumed)= ViO2 - VeO2
VCO2 (produced)= VeCO2- ViCO2

Front 16

What is Boyles Law?

Back 16

as pressure increases gas volume decreases.

Front 17

What is Charles Law?

Back 17

as temperature increases volume of gas increases.

Front 18

What is the respiratory quotient?

Back 18

RQ is the ratio of metabolic gas exchange at the cellular level or the ratio of CO2 produced to O2 consumed during the "breakdown" of a food in cellular metabolism for energy production.

Front 19

what is the RQ for carbohydrates and why is that?

Back 19

CHO requires the equivillent amount of O2 consumed in metabolism to breakdown 1 molecule of glucose resulting in an equivalent amount of CO2 & H2O produced:
C8H12O8 + 6O2 ---- 6H2O + 6CO2

therefore the RQ is 1.0

Front 20

what is the RQ for Fat and why?

Back 20

fat requires more O2 to metabolize due to the greater number of hydrogen molecules found in its structure, therefor the RQ is less the 1.0 for fat.

a pure fat will never go below 0.70

Front 21

what is the RQ for protien and why?

Back 21

Protien can be broken down to amino acids and used in metabolic pathways for energy but under "normal' conditions resting and submaximal, short duration exercise conditions, the contribution of AA's to metabolic energy is negligable.

therefore exercise physiologists do not often use RQ for Protein.

however it is calculated to be 0.82.

Front 22

What is RER?

Back 22

Respiratory Exchange Ratio is the ratio of the volume of CO2 expired (Vco2) to O2 consumed (Vo2) at the "mouth" level measured using open circuit spirometry when food is metabolized for energy production.

Vco2/Vo2 = RER

Front 23

What is the difference between RER and RQ? and when are they the same?

Back 23

RQ~ is the respiratory quotient and is the ratio of CO2 to O2 in the cell

RER~ is the respiratory exchange ratio and is the ratio of Vco2 to Vo2 measured at lung level.

the are the same under rest and sub-maximal exercise conditions.

Front 24

An individual averaged 3.22L O2/min(Vo2) and 2.78LCO2/ min(Vco2) during 30 minutes of exercise.
What is the RER?
What is the energy equivalent(kcal) at this rate of Vo2 and RER?
How much energy is expended for the 30 min of exercise?
What proportion of carbohydrates vs fat was used?

Back 24

1. Vco2/Vo2 = 2.78/3.22 = 0.86
2. RQ/RER of 0.86 = 4.875 kcal of O2 consumed thus 3.22L/min * 4.875 kcal/L = 15.7 kcal/min
3. 15.7 kcal/min *30min = 471 kcal
4. 54.1% CHO and 45.9% Fat

Front 25

when do RER values of 1.1 or greater appear? and why does it happen?

Back 25

during high intensity exercise because of the bicarbonate buffering (HCO3-) buffering of "anareobically" produced H+ accumulating in blood that leads to "extra" CO2 production.

Front 26

why does RER drop rapidly during recovery?

Back 26

it is due to the rapid drop in Ve (hypoventilation) and re-establishing blood bicarbonate equilibrium. thus Vco2 decreases more rapidly than Vo2.

Front 27

why does diet influence RER?

Back 27

low glycogen stores result in more fat metabolized, which in turn decreases RER values.

Front 28

What are the limitations of using indirect measurment?

Back 28

1. all indirect measurements involve error (90% for subject, 10% for techinical)
2. Vo2 must be at a steady state which assumes ATP is generally being regenerated aerobically.
3. Assume that protein is not being metabolized.
4. you should also examine rest and recovery energy expenditure to account for the total amount of energy used in an exercise session.
5. consideration must be given to exercise efficiency [both mechanical (ergomentry) & chemical (ATP)]

Front 29

what is the economy of movement?

Back 29

Vo2 needed to maintain velocity of movement & is the quantity of energy to perform an activity relative to the quality of performance of the activity.

Front 30

how do you determine % mechanical efficiency?

Back 30

%ME = work output
energy Expenditure *100

Front 31

Cycling a Monark ergometer at 4.00kg(kp) and 60.00 rpm; Vo2 of 3.22 L/min at an RER of 0.86.
Estimate total energy expenditure using Vo2 and RER.
Determine amount of mechanical work done cycling.
determine %ME.

Back 31

1. 3.22 L/min x 4.875 kcal/L = 15.70kcal/min
2. W= f*d = (4.00kg x 9.81m/s2) x (60rpm x 6m) = 14.13 kJ in 1.00 min or 3.38 kcal/min (1kJ = 0.2389 kcal)
3. Thus, %ME = (3.38kcal/min / 15.70 kcal/min) x 100 = 21.5% the remaining energy being lost as heat.

Front 32

what are the general factors influencing efficiency? why

Back 32

1. Age
2. Fiber type/ anatomy
3. Body mass
4.Skill/technique/sport issues
5. fitness level/ training
6. environmental conditions
7. engineering or construction of equipment.