What happens when the hypothalamic set point is elevated during fever?

What happens when the hypothalamic set point is elevated during fever?

• A. The body lowers heat production and promotes heat loss
• B. Shivering without vasoconstriction
• C. Shivering, vasoconstriction, and piloerection occur to raise heat
• D. No change in heat production

Answer: (C)

Raising the hypothalamic set point during fever signals the body that it should be warmer than its current temperature, so it activates heat-producing and heat-conserving mechanisms to reach that new target. Shivering increases heat production through involuntary muscle activity, while vasoconstriction reduces heat loss by narrowing skin blood vessels. Piloerection adds an insulating layer of air, further limiting heat loss. Together, these responses push body temperature upward toward the elevated set point. If the set point were lowered, the body would favor heat-dissipating responses instead, so the other options describe cooling or no change rather than the fever-driven rise.

Raising the hypothalamic set point during fever signals the body that it should be warmer than its current temperature, so it activates heat-producing and heat-conserving mechanisms to reach that new target. Shivering increases heat production through involuntary muscle activity, while vasoconstriction reduces heat loss by narrowing skin blood vessels. Piloerection adds an insulating layer of air, further limiting heat loss. Together, these responses push body temperature upward toward the elevated set point. If the set point were lowered, the body would favor heat-dissipating responses instead, so the other options describe cooling or no change rather than the fever-driven rise.