Problem 3
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Section 33.1: Visual Connection Questions
Chapter 33: The Animal Body: Basic form and function
Background and context
Thermoregulation is a process that helps the body to maintain a constant internal body temperature. Hypothalamus is responsible for thermoregulation. A change in body temperature will activate the sensors in the brain. The sensors send messages to the hypothalamus that send signals to other organs that will bring the temperature back to normal.
As shown in Figure 33.23, when the body temperature rises, the blood vessels dilate, increasing the blood flow to the skin and releasing the heat. The sweat glands produce sweat which lowers the internal body temperature. When the body temperature drops, the blood vessels become narrow, allowing less blood flow to the skin and hence retaining heat within the body core. The body shivers in cold weather to generate heat.