Ch 12 Quiz Review

Heat production can be increased through

All of these answers are correct:

non-shivering thermogenesis.
the action of thyroxine and catecholamines on cellular heat production.
shivering.

Regulation of body core temperature is important because

All of these statements are correct:

cellular structures and metabolic pathways are affected by temperature.
low temperatures can promote abnormal cardiac function (e.g., arrhythmias).
high temperature can alter the structure and function of enzymes.

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

30°C, 75% relative humidity

To ensure adequate hydration, athletes should

All of these are correct:

monitor fluid loses during exercise.
consume fluids (after exercise) equal to approximately 150% of weight loss.
consume fluids every 15-20 minutes during exercise.

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

Body temperature is a balance between heat loss and heat gain

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:

total heat produced: 250 kcal x 0.80 = 200 kcal
200 kcal/580 kcal/L = 0.344 liters

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

580

The primary source of heat production during exercise is

the contracting skeletal muscles.

Which of the following is a potential mechanism of heat gain on a hot and sunny day outside?

radiation

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

conduction

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

homeotherms

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

increased free radical production in the active skeletal muscles.

The primary adaptations that occur during heat acclimatization are

an increased plasma volume, earlier onset of sweating, and a higher sweat rate.

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

radiation

The higher the relative humidity and air temperature, the __________________.

lower the vapor pressure gradient between the skin and the environment

Cold acclimation results in which of the following physiological adaptations?

All of these answers are correct:

improved ability to prevent large decreases in skin temperature during cold exposure.
improved ability to sleep in cold environments.
increased nonshivering thermogenesis.

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°C = 0.83 kcal/kg
Therefore, the total increase in body temperature following exercise would be:

3.86°C

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

results in a more rapid onset of muscular fatigue.

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

both peripheral vasoconstriction and shivering are correct

An increase in body core temperature typically results in

sweating

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

All of these answers are correct:

Repeated bouts of exercise in warm or hot environments increase their synthesis in cells.
They stabilize and refold damaged cellular proteins.
They assist cells in tolerating heat stress.

The body's thermostat is located in the

preoptic-anterior hypothalamus.

Heat acclimatization occurs generally within

7-14 days

During exercise ____________ of energy produced is released as heat.

70-80%

Endurance exercise performance 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?

respiratory dysfunction

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

All of these answers are correct:

amount of exposed skin.
convective currents.
ambient temperature and relative humidity.