lab 9 Flashcards

1
Q

Define thermoregulation

A

physiological or behavioral responses by which organisms regulate body temperature

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2
Q

organisms are categorized into what two categories and how are they divided

A

endotherms or ectotherms

  • divided based on how they primarily regualte body temperature
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3
Q

Explain what endothermic species are

A

such as mammals, warm their tissues from metabolic heat production

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4
Q

Explain what ectothermic species are

A

such as reptiles and amphibians
* depend on the external environment for warming

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5
Q

deviations away from normothermia can lead to what

A

lead to physiological consequences

  • decrease in core temp of 10 degrees C or elevations in core above 5 degrees C can be fatal
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6
Q

Where is the thermal gradient

A

from deep body temperature (core temperature) to the shell (skin) temperature

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7
Q

What is core temperature and what locations can you find them

A

temperature often measured by clinicians and researchers

  • ie. oral, axillary, tympanic, rectal, temporal
  • or esophageal and GI temp
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8
Q

How is esophageal temp measured

A

measured by inserting a thermometer through nose into esophagus

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9
Q

How is esophageal temp measured

A

measured using an ingestible pill sensor

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10
Q

What is normal core temperature

A

around 37 degrees C

  • variations due to circadian veriation in male and female and menstrual phase in female
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11
Q

Stage one hypothermia occurs when?

A

at or below a core temp of 35 degrees C

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12
Q

At 32 degrees C what symptoms occur

A

hallucinations, delirium, excessive sleepiness

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13
Q

what are signs of hypothermia

A

shivering, loss of limb movement, blueness in the skin, confusion

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14
Q

At temp b/t 24 and 26 degrees C what can occur

A

respiratory or cardiac arrest may occur –> comatose or death

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15
Q

What is the physiological response to an increase in core temperature

A

increased sweatrate, HR, and breathing rate

  • if continues to increase, nausea, dizziness, weakness, and fainting may occur
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16
Q

Heat exhaustion and and heat stroke may be observed in temps that exceed what

A

40 degrees C and higher and death certain at 45 degrees C

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17
Q

What is convection

A

body heat is lost to surrounding air, which becomes warmer, rises and is replaced with cooler air

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18
Q

What is radiation

A

body heat is lost to nearby objects without physically touching them

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19
Q

What is evaporation

A

body heat causes perspiration which is lost from the body surface when changed from liquid to vapor

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20
Q

What is conduction

A

body heat is lost to nearby objects though direct physical touch

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21
Q

If the environment is cooler than the body, heat will be lost from the body via what processes

A

radiation, conduction, and convection

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22
Q

as environmental temperature increases, heat loss via what decreases and the importance of what type of heat loss increases

A

radiation, conduction, and convection decrease but evaporative heat loss increases

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23
Q

As environmental temperature exceeds body temperature the thermal gradient for conduction, convection, and radiation does waht

A

is reversed and the body gains heat through these mechanisms

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24
Q

What is the only mechanism for heat loss

A

evaporation

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25
Q

the capacity for evaporative heat loss is affected by what

A

by the environment and primarily via humidity and ambient temperature

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26
Q

as humidity and ambient temperature increase the max capacity for evaporative heat loss increases or decreases

A

decreases

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27
Q

when humidity is near 100% and ambient temp is > 30 degrees C what happens to evaporative heat loss

A

evaporative heat loss is minimal

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28
Q

What is the Wet Bulb Globe Temperature (WBGT) index

A

whether a given environment is safe or dangerous

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29
Q

What is the equation for the Wet Bulb Globe Temperature index

A

WBGT = 0.7(Tw) + 0.2(Tg) + 0.1(Td)

30
Q

What is Tw

A

temperature of the wet bulb which is influenced by the level of humidity

31
Q

What is Tg

A

temperature of the black globe which measures radiant heat

32
Q

What is Td

A

actual ambient air temperature indivated by the dry bulb

33
Q

What happens to heat produced that is not lost

A

stored in body tissues and this will rise body temperature

34
Q

what is the equation for body heat gain during exercise

A

heat produced - heat loss

35
Q

What is specific heat of the body

A

amount of heat required to raise body temperature by 1 degrees C

35
Q

What is the specific heat in humans

A

0.83 kcal/kg * body mass

36
Q

What is the equation for heat requried to raise body temperature 1 decrees C (kcal)

A

(0.83 kcal/kg)(body mass (kg))

37
Q

exercise and heat stress does what to sweat

A
  • exercise increases sweat rate
  • heat stress exacerbates sweat loss
38
Q

with high sweating what happens to the body

A

cuases dehydration and reductions in plasma volume (NOT THE SAME)

39
Q

changes in plasma volume are influenced by what

A

alteration in total body water AND distribution of water b/t intravasular, instersitital, and intercellular compartments

40
Q

Body water loss during exercise can occur through what four primary mechanisms

A
  1. sweat loss
  2. metabolic mass loss (MML)
  3. respiratory water loss (RWL)
  4. urinary water loss (UWL)
41
Q

sweat loss is equal to what

A

body mass change following exercise

42
Q

if a subject loses 1 kg of body mass during 1 hr of exercise their sweat loss is estimated as what in mL

A

1000 ml (1g/mL)

43
Q

For calculating sweat loss what do you need to keep constant

A

subject wearing dry clothing

44
Q

is the assumption that sweat loss is the only mechanism of water loss correct

A

NO it is incorrect

45
Q

What is metabolic mass loss (MML)

A

restulting from O2/CO2 exchange

46
Q

What is the equation of metabolic mass loss

A

VO2STPD (L/min) * [((44 g/mol) * RER) - 32 g/mol) / 22.4 L]

47
Q

What is the respiratory water loss (RWL) and what is the formula

A

resulting from ventilation

respiratory water loss = (0.019 * VO2STPD (L/min)) * (44-PH2O)

48
Q

What is urinary water loss (UWL) formula

A

Urinary water loss (g/min) = (urine volume (mL) / exercise duration (min) ) * density of water 1g/1mL

49
Q

What is the equation for sweat loss

A

Total body mass - MML - RWL - UWL

50
Q

At a constant absolute intensity (a given cycling power output or running speed) what happens to exhaustion

A

time to exhaustion is shortened

51
Q

What two things may reduce neuromuscular drive

A
  • high core and potentially brain temperatures
  • reduce metabolic heat production and potentially prevent excessively high temperatures
52
Q

what is the primary mechanism impairing endurance training in the heat

A

cardiovascular instability

53
Q

Heat does what to the cardiorespiratory system

A

increases HR, reduces SV, reduction in plasma and blood volume, and requires a dramatic increase in skin blood flow

54
Q

what other mechanisms impair performance

A
  • accelerated glycogenolysis –break down of glycogen into glucose
  • increased free radical production
55
Q

what is acclimatization

A

adaptations resulting from changes in the natural environment

56
Q

what is acclimation

A

adaptations resulting from exposures produced in a controlled lab setting

57
Q

Heat acclimatization/acclimation includes what symptoms

A

increase in plasma volume, earlier onset of sweating, higher sweat rate, reduced salt loss in sweat, reduced skin blood flow, and increased synthesis in heat shock proteins

58
Q

the reduced loss of sodium is sweat that results from acclimatization and acclimation which does what?

A

minimizes the elecroyte loss that occurs during exercise

  • HSPs synthesized in response to stress and protect cells from heat damage
59
Q

what is the result with an increase in plasma volume that occurs with acclimatiztaion or acclimation

A

increases sweating capacity, increase SV, maintain blood volume, allows body to store more heat without an increase in core temperature

60
Q

What happens to evaporative heat loss vs convective and radiative heat loss during exercise as the temperature increases

A

evaporative heat loss increases exponentially and convenctive and radiative heat loss decreases exponentially

61
Q

What does the dry-bulb measure in the wet bulb/dry bulb thermometer

A

dry bulb measures temperature

62
Q

the comparison between the wet and dry bulb termperatures gives you what

A

gives you the relative humitidy in the air

63
Q

if a wet bulb and dry bulb displayed the same temperatures what you conclude about humitidy

A

there is 100% humidity

64
Q

What happens to free radical production with heat-related exercise fatigue and why

A

increased free radical production = damage to muscle contractile protein

65
Q

During a wet bulb globe tempreature it is used to estimate what

A

estimate the effect of temperature, humidity and solar radiation on humans

66
Q

With a high brain temperature what is effected and why

A

neuromuscular drive = reduction in motor unit recruitment

67
Q

What happens to muscle glycogen with heat-related exercise fatigue

A

accelerated muscle glycogen metabolism and hypoglycemia

68
Q

dehydration of what % can impair performance

A

dehydration of 1-2% body weight

69
Q

what are the 6 primary adaptations that occur as a result of heat acclimatization

A
  1. increased plasma volume
  2. earlier onset of sweating
  3. higher sweat rate
  4. reduced sodium chloride loss in sweat
  5. reduced skin blood flow
  6. increased heat shock proteins in tissues