Deck 13: Temperature Regulation

Question 1

The body's thermostat is located in the

A)cerebellum.
B)brain stem.
C)hypothalamus.
D)thalamus.

Answer 1

C

Question 2

Compared to exercise in a cool environment,prolonged exercise in the heat

A)decreases the production of free radicals in the working muscles.
B)increases muscle blood flow.
C)decreases muscle lactate production.
D)results in a more rapid onset of muscular fatigue.

Answer 2

D

Question 3

The primary adaptations that occur during heat acclimatization are

A)a decreased plasma volume,earlier onset of sweating,and higher sweat rate.
B)an increased plasma volume and lower sweat rate.
C)an increased plasma volume,earlier onset of sweating,and a higher sweat rate.
D)a decreased plasma volume,earlier onset of sweating,and a lower sweat rate.

Answer 3

C

Question 4

The transfer of heat from the body into molecules of cooler objects in contact with its surface is called

A)radiation.
B)conduction.
C)convection.
D)evaporation.

Question 5

During exercise ____________ of energy produced is released as heat.

A)<10%
B)20-30%
C)50%
D)70-80%

Question 6

Regulation of body core temperature is important because

A)cellular structures and metabolic pathways are affected by temperature.
B)low temperatures can promote abnormal cardiac function (e.g. ,arrhythmias).
C)high temperature can alter the structure and function of enzymes.
D)All of the above statements are correct.

Question 7

Which of the following could be a mechanism of heat gain in a hot and sunny environment?

A)radiation
B)conduction
C)evaporation
D)radio waves

Question 8

Humans and other animals that maintain a rather constant body temperature are called

A)cold-blooded animals
B)homeotherms
C)poiklotherms
D)None of the above answers are correct

Question 9

In response to a decrease in body temperature,humans often exhibit ____________ upon response to cold.

A)peripheral vasodilation
B)peripheral vasoconstriction
C)shivering
D)both B and C are correct

Question 10

Hypothermia is defined as a significant

A)decrease in skin temperature.
B)decrease in body core temperature.
C)increase in body core temperature.
D)decrease in skin blood flow.

Question 11

Exercise in the heat is associated with accelerated fatigue due,in part,to

A)decreased muscle glycogen utilization.
B)increased free radical production in the active skeletal muscles.
C)decreased lactate production.
D)all of the above answers are correct.

Question 12

The primary source of heat production during exercise is

A)the heart.
B)the gastrointestinal tract.
C)through the action of thyroxine and catecholamines.
D)the contracting skeletal muscles.

Question 13

Heat production can be increased through

A)shivering.
B)non-shivering thermogenesis.
C)the action of thyroxine and catecholamines.
D)All of the above answers are correct.

Question 14

At high environmental temperatures,which of the following variables impact the amount of heat loss by evaporation ?

A)convective currents.
B)ambient temperature and relative humidity.
C)amount of exposed skin.
D)all of the above answers are correct.

Question 15

An increase in body core temperature results in

A)cutaneous vasoconstriction.
B)cutaneous vasodilation.
C)thyroxine release.
D)shivering.

Question 16

Heat acclimatization occurs generally within

A)1 to 2 days.
B)less than 7 days.
C)7 to 14 days.
D)15 to 30 days.

Question 17

Which of the following statements about body temperature homeostasis is correct?

A)Body temperature is a balance between heat loss and heat gain.
B)Core temperature is constantly maintained at 34 $\degree$ C.
C)Skin temperature is usually equal to core temperature.
D)None of the above statements are correct.

Question 18

The higher the relative humidity,the __________ vapor pressure gradient between the skin and the environment.

A)higher
B)lower
C)No relationship exists between relative humidity and vapor pressure.
D)None of the above answers are correct

Question 19

Evaporation of one liter of sweat would result in the loss of ________ kcal of heat.

A)100
B)500
C)540
D)580

Question 20

The principal means of heat loss at rest in a cool indoor environment (20 $\degree$ C/low humidity)is via

A)radiation.
B)conduction.
C)evaporation.
D)convection.

Question 21

Prolonged exercise results in a significant increase in body core temperature.Calculate the increase in body core temperature during exercise given the following: Total energy expenditure during exercise = 600 Kcal
Exercise efficiency = 20%
Total heat stored during exercise = 192 Kcal
Subject body weight = 60 Kg
Amount of heat required to increase body temperature by 1 $\degree$ C = 0.83 kcal/kg
Therefore,the total increase in body temperature following exercise would be:

A)1.86 $\degree$ C
B)2.86 $\degree$ C
C)3.86 $\degree$ C
D)4.86 $\degree$ C

Question 22

In general,during exercise in a thermoneutral environment,the increase in core temperature is directly related to the exercise intensity.

Question 23

During exercise,body temperature is regulated by making adjustments in the amount of heat that is lost.

Question 24

Pre-cooling the body before performing prolonged exercise in a hot and humid environment has been shown to significantly improve performance.

Question 25

Training in a cool environment while wearing warm clothing (e.g. ,sweats)promotes heat acclimatization.
37.Dehydration that results in a loss of 1-2% of body weight is sufficient to impair exercise performance.

Question 26

The evaporation of 1,000 ml of sweat results in the loss of 1,000 kcal of heat.

Question 27

Individuals with a high percentage of body fat have an advantage over lean individuals in tolerance to cold.

Question 28

Which of the following statements are true about heat shock proteins?

A)Repeated bouts of exercise in warm or hot environments increase their synthesis in cells.
B)They stabilize and refold damaged cellular proteins.
C)They assist cells in tolerating heat stress.
D)All of the above answers are correct.

Question 29

Calculate the total evaporation of sweat necessary to prevent heat gain in the body given the following information: Total body energy expenditure = 250 Kcal
Exercise efficacy = 20%
Evaporation of 1000 ml of sweat results in 580 Kcal of heat loss
Therefore,the total evaporation of sweat necessary to prevent body heat gain in these conditions is:

A)0.276 liters
B)0.344 liters
C)0.166 liters
D)None of the above answers are correct

Question 30

Cold acclimatization results in an improved ability to sleep in a cold environment.

Question 31

During exercise in a hot and humid environment,heat loss via evaporation is decreased compared to exercise in a cool and low humidity environment.

Question 32

A high percentage of body fat results in an increased ability to lose body heat during exercise.

Question 33

Which of the following conditions would result in the highest vapor pressure in the air?

A)20^oC,100% relative humidity
B)30^oC,75% relative humidity
C)30^oC,50% relative humidity
D)25^oC,75% relative humidity

Question 34

Cold acclimation results in which of the following physiological adaptations?

A)increased nonshivering thermogenesis.
B)improved ability to prevent large decreases in skin temperature during cold exposure.
C)improved ability to sleep in cold environments.
D)All of the above answers are correct.

Question 35

Exercise performance in endurance events is impaired in a hot and humid environment.Which of the following physiological factors does NOT have a negative impact on exercise performance in a hot and humid environment?

A)accelerated muscle fatigue
B)cardiovascular dysfunction
C)respiratory dysfunction
D)central nervous system dysfunction