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Oxygen physiology > Energy Expenditure And Temperature > Flashcards

Energy Expenditure And Temperature Flashcards

1
Q

Caloric Theory

A

Heats consists of a self-repellent fluid (“caloric”) that can be transferred from one body to another, but cannot be created or destroyed.

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2
Q

Caloric Theory was superseded by

A

the mechanical theory of heat

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3
Q

Lavoisier and LaPlace Calorimeter (1780)

A

Placed animal in chamber with insulation all around it (insulated from outside environment). Air flow, packed with ice. Experiment evaluated amount of heat produced by the mouse (measured by amount of ice that melted into water). 80 kcal of heat melts 1 kg of ice. How do you measure thermal production Measure heat based on what it does to ice Body heat of guinea pig melts ice Ice into an isolated chamber it wont melt but if you add a guniea pig its body heat will melt. Air needs to be able to enter and exit. Heat only leaves the chamber because of ice melting and then you measure the amount of water collected and get heat.

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4
Q

Heat according to caloric theory is similar too

A

phlogostin

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5
Q

Joules work on heat

A

Theoretical experiment: Chamber mixed with water. Drop a 427 kg weight from height of one meter. Transfer of energy into spinner. When weight falls, will raise temperature by 1°C. 427 mkg work → 1 kcal heat. 427 mkg = 1 kcal heat mechanical energy → 0.56 g (mechanical) give 1 kcal chemical energy → 0.465 x 10-10g = 1 kcal nuclear energy 1 BTU = 1 lb water raised 1°F = 252 calories Calorie = energy it takes to increase the temperature of one gram of water by 1°C Conversion between Joules and calories: 1 calorie = 4.1833 Joule

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6
Q

427 mkg

A

1 kcal heat mechanical energy

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7
Q

0.56 g (mechanical) give

A

1 kcal chemical energy

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8
Q

0.465 x 10^-10g

A

1 kcal nuclear energy

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9
Q

Conversions

A

427 mkg = 1 kcal heat mechanical energy → 0.56 g (mechanical) give 1 kcal chemical energy → 0.465 x 10-10g = 1 kcal nuclear energy

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10
Q

1 BTU

A

1 lb water raised 1°F = 252 calories A lb is half a liter but 1 degree farenheight is about half a degree centigrade 1 btu equals approx 1 kilojoule

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11
Q

Calorie

A

energy it takes to increase the temperature of one gram of water by 1°C

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12
Q

Conversion between Joules and calories:

A

1 calorie = 4.1833 Joule

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13
Q

kcal

A

food calorie which equals 1000 small calories which equals 4186 joules

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14
Q

Joules unit conversion

A

1 J = (kg x m^2)/s^2 = N x m = W x s = Pa x m^3 = C x V

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15
Q

Specific heat of water:

A

1 calorie = 4.1855 J = “15° calorie” (14.5°C → 15.5°C, typical calorie) 4.184 J = “thermochemical calorie” (0°C → 1°C) - physiologist use this one 4.190 J = “mean calorie” (0°C - 100° C) (avg energy to move 1 g of water 1 C)

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16
Q

Resting Metabolic Rate

A

70 kcal/hour 250 mlO2/min 85 Watts

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17
Q

Exercise Increases the RMR

A

400-600 kcal/hr – 5x increase in calorie/heat production along with rr/circulatory rates and o2 consuption and is pretty constant across mid range mammals.

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18
Q

Athletes and Thouroghbreads

A

Athletes and thoroughbread horses can go from 10-20x RMR during exercise They have a lower resting rate and a larger maximum rate

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19
Q

Shivering increases energy production by

A

400%

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20
Q

Q10

A

relationship btw enzymatc activity at 2 different temperatures in bio tissues q10 is 2 meaning for an increase of 10 degrees activity will double. We use it in the other direction to lower in kids we can go really low. A 20 degree drop in temperature reduces the rmr by 4

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21
Q

Carbs and Protein

A

4 kcal/gram

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22
Q

Alcohol

A

7 kcal/gram

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23
Q

Fats

A

9 kcal/gram Fats are the most concentrated form

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24
Q

To maintain body weight you need

A

15 cal/lb (RMR)

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25
Q

A 200 lb person would need to eat how many calories per pound to maintain his weight

A

15 calories/lb so about 3000 calories to gain or lose weight

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26
Q

3500 kcal/lb to

A

gain or lose weight - dependent on water balance

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27
Q

Most of metabolism is set to

A

gain weight i.e. increase fat stores for leaner times

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28
Q

Exercise increase skeletal muscle and rmr by

A

Exercise increase skeletal muscle and rmr by 5x so contribution decreases for these 5 and increases for skeletal muscle reduce for these 5 and increase

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29
Q

Exercise increase skeletal muscle and rmr by

A

Exercise increase skeletal muscle and rmr by 5x so contribution decreases for these 5 and increases for skeletal muscle reduce for these 5 and increase

30
Q

Brain

A

2 percent body mass uses 20% energy, blood, O2

31
Q

Ratio of central nervous system to body metabolism in vertebrates

A

Mink et al Am J Physiol 241:R203-R212, 1981 most vertebrate species use 2-8% of their basal metabolism for the central nervous system (CNS). “of all animals, man has the largest brain in proportion to his size,”- Aristotle Domesticated animals use less (bred for size and dumbness?) <2% Primates use more (>10%); also mouse 8.5%; but shrew 1.5% Very large animals also low; ostrich 0.7%, elephant 2.0%, whale 0.5% Humans need to use less of their brain to take care of them selves percent is how much of their energy used to support CNS more energy used for your brain less function

32
Q

Mechanical Work is

A

easily defined physiologically using muscles

33
Q

Chemical Work

A

is difficult to define but is used in assumptions to quanitfy the work done by the brain Moving ions, neurotransmitters (nerve cells) Establishing “batteries” = energy stored in ion gradients Mitochondrial “fuel cell” to recharge batteries Work defined by energy expenditure by muscles Brain is hard to relate to the physics of work – most chemical work – use energy based on ATPase and pumps and how much work done to make the pumps work

34
Q

Brain O2 consumption

A

1.5 umol/g/min = 3.5 ml/100g/min

35
Q

70 Kg Man has ____ Kg brain

A

1.4 Kg brain

36
Q

Brain consumes ______ O2/day

A

Brain consumes 3 Moles O2/day 67L O2/day = about 15 balloons

37
Q

Brain makes ______ water per day

A

6 Moles of water per day (18 g/M, 18 mL/M = 108 mL H2O/day)

38
Q

The brain Makes ______ Moles of ATP

A

Makes 18.12 Moles of ATP (~9 Kg; 20 lb) / day 7mM/min = 10 M ATP a day;

39
Q

In an Normal Young Adult Male Cerebral Blood Flow is

A

57 ml/min/100g of brain tissue 798 ml/min/total brain (1400 grams) Brain about a liter a min bec 1/5 co and co 5 liters is led bulb about as efficient as mito

40
Q

In an Normal Young Adult Male Cerebral O2 consumption is

A

3.5 ml/min/100g of brain tissue 49 ml/min/total brain (1400 grams)

41
Q

In an Normal Young Adult Male Cerebral glucose utilization is

A

5.5 mg/min/100g of brain tissue 77 mg/min/total brain (1400 grams)

42
Q

brain uses energy

A

in small burst rather than one shot like most energy production

43
Q

The 10% Brain Myth

A

Humans only use 10% of their brain and if we use more of it at one time we can increase our mental abilities it is false

44
Q

Proof 10% Brain Myth is False: Energy

A
  1. Look at the energy!!! Resting brain metabolism is 2 times that of brain with suppressed activity Maximum cerebral metabolic rate is about 2.5 times resting metabolism Metabolic scope is thus about 5. Thus, at rest the brain is using using about 20% of our useful energy capacity, Rmr – darkned room 50 ml/min Zero activity – 02 is half 25ml/min Comp activate – seizure – increse by 2 times ½ to 2 and a 1/2 gives the 1/5 ratio
45
Q

Proof 10% Brain Myth is False: Full Activation

A
  1. Full activation, all nerve cells firing at once is non-functional (represented by status epilepticus. So, for best brain function focus narrows the number of nerve cells used at any one time. - Focal and Local
46
Q

Brain Use Facts: Truths

A
  1. There is no part of the brain that is not used at some time or other. 2. There is some activity in every part of the brain at all times 3. The brain uses a lot of energy. If 90% were unnecessary there would a large survival value to smaller, more efficient brains. Brains. An inefficient brain would be unlikely to evolve. 4. Because of the constraints of the female pelvic opening and the difficulties of childbirth due to a large brain with large skull, evolutionary pressure would select against a brain where 90% of the mass is redundant.
47
Q

Metaphor

A

Brain as a piano 88 keys use all keys at some point but only use 10 keys at any one time

48
Q

Brain Energy Consumption

A

20% of cardiac output goes to the brain; 20% of O2 consumption of the body at rest comes from the brain. Flaming marshmallow analogy → oxidation of glucose (in brain, happens in steps as opposed to continuously)

49
Q

Temperature, RMR, Life Span

A

Low temperature environments - decrease RMR and increase life span

50
Q

Homeothermy vs Poikilothermy

A

Regulation of internal body temperature

51
Q

Homeothermy

A

Regulation of internal body temperature

52
Q

Poikilothermy

A

Internal body temperature varies

53
Q

Endothermy vs Ectothermy

A

Regulation by exchange with environment

Endotherm: internal heat generation mechanisms

Ectotherm: environment causes temperature changes

54
Q

Endothermy

A

produce heat to control body temperature - warm blooded

55
Q

Ectothermy

A

Use ambient temperature to control blood temperature with very little or neglibile heat production - cold blooded

56
Q

Warm Blooded vs Cold Blooded

A

Set point vs relative temperature

Human enzymes optimized to work at body temperature

Other enzymes can work at variable temperatures

Dinosaurs have trouble cooling off due to size

57
Q

Average Temperature of Mammals

A

37-38ºC

58
Q

Average Temperature of Birds

A

39-40ºC

59
Q

Average Temperature of Marsupials

A

36ºC

60
Q

Average Temperature of Monotremes

A

31ºC

They are homeotherms and endotherms

61
Q

Temperature Facts

A

Birds evolved from dinosaurs Advantage constant temp – effient enzymes at that range Higher temp – more efficient metabolism – need to eat more

62
Q

Modes of Heat Transfer

A

Conduction – needs something to carry it – occurs when objects are in direct contact Convection – via fluid from hot to cold needs contact

Radiation - waves

Evaporation – water changing state

or

Conduction: requires contact

Convection: carries by another fluid i.e. air or water

Radiation: electromagnetic energy

Evaporation: water evaporating from skin, endothermic to cause cooling

63
Q

Heat Balance Equation

A
64
Q

Modes of Heat Transfer Equations

A

A lot of this is based on gradients all from ficks law of diff gradients are impt for energy

65
Q

Van’t Hoff relation & Physiological Q10

A
66
Q

Svante Arrhenius (1859 – 1927)

A

Arrhenius used absolute temp and co2 variations and climate changes

67
Q

Surface Law / Surface Rule

A

§Heat loss is from the surface, small animals have increased S / V and so have increased heat loss which must be balanced by increased metabolic heat production to keep warm

Smaller u r the more heat u lose so smaller higher met rate

Heat loss proportional to surface area – E C and R are directly proportional to surface area

Heat production is a function of mito volume

Animal smaller volume is bigger

Larger animal produce more vol wise but smaller area to get rid of it

Area to vol is 3 to 2

68
Q

Bergmann’s Rule

A

1847

Warm blooded animals in colder climates are larger in body size than relatives in warm climates

Heat loss related to surface area

Heat production is related to volume/mito

Some wiggle room

Small animal loses heat faster than a large animal, needs higher metabolic rate in order to keep warm

Hypothesis: lose less heat because of the surface-to-volume ratio

Easier to keep warm with larger body size

Equatorial vs temperate

69
Q

Body Temp, RMR, and Life Span

A

Decrease body temp live longer bec lower met rate

Lower met rate increase lifespan

Increase body size increase life span but lower met rate

Lower met rate increase life span

70
Q

The relation of body weight to metabolic weight and organ size

A
71
Q

Study in mice

A

Reduction of core body temperature resulted in an extended lifespan

Lower metabolic rate = greater lifespan

Oxygen physiology (6 decks)

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