[Campbell Biology P.938] Based on Figure 40.17, 'The thermostatic function of the hypothalam... | Practice Question

Based on Figure 40.17, 'The thermostatic function of the hypothalamus in human thermoregulation,' which of the following statements accurately describes a mechanism by which the human body regulates its temperature?

  • A: When body temperature increases, the hypothalamus activates warming mechanisms, leading to shivering.
  • B: In cold surroundings, blood vessels in the skin constrict to reduce heat loss, and skeletal muscles may contract to generate heat through shivering.
  • C: Sweat glands secrete sweat which, upon evaporation, warms the body.
  • D: When body temperature decreases, the hypothalamus signals blood vessels in the skin to dilate, radiating heat from the surface.

Explanation

Figure 40.17 clearly illustrates that when body temperature decreases e.g., in cold surroundings , the hypothalamus activates warming mechanisms. These include blood vessels in the skin constricting to divert blood from the surface, reducing heat loss, and skeletal muscles rapidly contracting shivering to generate heat.