Deck 13: Temperature Regulation

Question 1

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

Answer 1

False

Question 2

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 2

C

Question 3

Exercise in the heat is associated with accelerated fatigue due to

A) increased muscle glycogen utilization.
B) increased free radical production.
C) increased lactate production.
D) all of the above.

Answer 3

D

Question 4

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

A) higher
B) lower
C) There is no relationship between relative humidity and vapor pressure.

Question 5

The body's thermostat is located in the

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

Question 6

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 7

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 maintained at 34 $\degree$ C.
C) Skin temperature is usually equal to core temperature.
D) All of the above statements are correct.

Question 8

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

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

Question 9

Hypothermia is defined as a large

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

Question 10

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

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

Question 11

During exercise ____________ of energy produced is released as heat.

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

Question 12

In general, at high environmental temperatures, the most important variable determining heat loss by evaporation is/are the

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

Question 13

An increase in core temperature results in

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

Question 14

Heat production can be increased voluntarily through

A) shivering.
B) non-shivering thermogenesis.
C) the action of thyroxine and catecholamines.
D) exercise.

Question 15

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

Question 16

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 17

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

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

Question 18

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

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

Question 19

In response to a decrease in body temperature, the __________ initiates the release of norepinephrine, which increases the rate of cellular metabolism.

A) cerebrum
B) posterior hypothalamus
C) anterior hypothalamus
D) medial hypothalamus

Question 20

Which of the following is true of heat shock proteins?

A) Repeated bouts of exercise in warm or hot environments decrease their synthesis.
B) They destabilize and unfold functional cellular proteins.
C) They help the body tolerate heat stress.
D) They help the body tolerate cold stress.

Question 21

The most accurate way to measure core body temperature is with a tympanic thermometer.

Question 22

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

Question 23

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

Question 24

Dehydration that results in a loss of 1-2% of body weight is sufficient to impair exercise performance.

Question 25

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

Question 26

Training in a cool environment while wearing warm clothing (e.g., sweats) promotes heat acclimatization.

Question 27

Cold adaptation results in a reduction in the mean skin temperature at which shivering begins.

Question 28

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