Free Thermoregulation MCQs with Answers

• A. medulla oblongata
• B. hypothalamus
• C. cerebellum
• D. skin itself

Explanation: The hypothalamus contains receptors that monitor the temperature of the blood flowing through it and also receives information from…

• A. constrict, so less blood reaches the surface
• B. are unaffected, since only sweating matters
• C. dilate, so more blood flows near the surface and more heat is lost
• D. carry blood away from the skin into deeper shunt vessels

Explanation: Vasodilation of the arterioles lets more warm blood flow through the surface capillaries, so heat is lost by radiation and conduction and…

• A. sweat is colder than the body
• B. sweat carries away dissolved urea
• C. the sweat glands use up energy in secreting it
• D. evaporation of the water in sweat takes latent heat from the skin

Explanation: Changing liquid water into vapour requires a large amount of latent heat, and that heat is drawn from the skin surface, so the body cools…

• A. rapid involuntary muscle contractions release heat from respiration
• B. it increases the blood flow to the skin
• C. it reduces the surface area of the body
• D. it stops sweat being produced

Explanation: The muscles contract and relax rapidly without doing any useful external work, so almost all the energy released by increased respiration…

• A. dilation of the surface capillaries
• B. contraction of the erector pili muscles, which pull the hairs upright
• C. the emptying of the sweat glands
• D. the thickening of the subcutaneous fat layer

Explanation: Each hair has a small erector muscle that pulls it erect, and in a furry mammal this traps a thicker layer of still air as insulation.

• A. always live in warm climates
• B. have a body temperature that follows the temperature of the surroundings
• C. generate most of their body heat from their own metabolism and hold it nearly constant
• D. are unable to lose heat through the skin

Explanation: An endotherm keeps its core temperature steady using heat from respiration, which lets enzymes work at their optimum whatever the weather…

• A. Vasodilation & sweating
• B. Vasoconstriction
• C. Shivering
• D. Renin secretion

Explanation: Cooling in hot conditions depends on dilating the skin arterioles so more warm blood reaches the surface and on evaporating sweat, which…

• A. Vasodilation
• B. Vasoconstriction
• C. Panting
• D. All of these

Explanation: Panting increases evaporation of water from the respiratory tract, and evaporation removes heat from a dog's body.

• A. 35 oC
• B. 36 oC
• C. 37 oC
• D. 38 oC

Explanation: The average internal temperature of a healthy human is approximately 37 °C, maintained by thermoregulatory mechanisms despite changes in…

• A. Walter Bradford Cannon
• B. Anselme Payen
• C. Jons jacob Berzeliis
• D. None of these

Explanation: Walter Bradford Cannon introduced the term homeostasis for the maintenance of a relatively stable internal environment.

• A. Thermal adaptation shown by animals
• B. wind adaptation shown by animals
• C. adaptation of animals to escape from predators
• D. none of the above

Explanation: Hibernation and aestivation are thermal adaptations in which animals reduce activity and metabolism during very cold or very hot…

• A. Endotherms
• B. Ectotherms
• C. Heterotherms
• D. Homeotherms

Explanation: Bats and hummingbirds are heterotherms because their body temperature and metabolic rate can vary, especially during torpor or periods of…

• A. 26 - 28°C
• B. 36 - 38°C
• C. 46 - 48°C
• D. 56 - 58°C

Explanation: Human enzymes and cells function best near 37°C, so normal mammalian body temperature is approximately 36 to 38°C.

• A. There is a definite control system that regulates the homeostatic activities
• B. Homeostatic mechanisms keep the internal environment fixed despite of wide changes in external environment
• C. Because of this the fluctuations of internal environment are of extremely narrow range as compared to that of external environment
• D. All are correct

Explanation: Homeostasis does not keep the internal environment completely fixed; it maintains variables within a narrow range despite external…

• A. Change in membrane protein composition.
• B. Change in the solute composition of the cell membrane which prevents crystallization.
• C. Increase in proportion of unsaturated fatty acids.
• D. Development of heat shock proteins.

Explanation: Increasing unsaturated fatty acids keeps membrane lipids fluid at low temperatures because their bends prevent tight packing and crystal…

• A. Positive feed back
• B. Negative feed back
• C. Feed back
• D. Osmoregulation

Explanation: Negative feedback opposes a change: when body temperature rises, mechanisms such as sweating and vasodilation lower it toward the normal…

• A. Fore brain
• B. Hind Brain
• C. Thalamus
• D. Hypothalamus

Explanation: The hypothalamus contains the body's temperature-regulating centre and compares blood temperature with a set point to coordinate heat-loss…

• A. Protective
• B. Destructive
• C. Constructive
• D. Aggressive

Explanation: Pyrogens raise the hypothalamic temperature set point and trigger fever, which can hinder the growth or replication of some pathogens and…

• A. Fresh water mammals
• B. Terrestrial mammals
• C. Marine Mammals
• D. Flying mammals

Explanation: Marine mammals such as whales and seals possess blubber, a thick fat layer that reduces heat loss in cold water and also provides energy…

• A. Endotherms
• B. Ectotherms
• C. Heterotherms
• D. Homeotherms

Explanation: Ectotherms depend largely on environmental heat to regulate their body temperature, so fishes, most invertebrates and amphibians are…