Think about how your body reacts on a hot day and on a cold day. Sweating and shivering are both ways of maintaining homeostasis.
z On a hot day we sweat to remove heat from the skin. Our blood vessels dilate (become wider) to allow more heat to be lost.
z On a cold day we shiver and these small movements create warmth. Our blood vessels constrict (become narrower) to keep heat in the body.
20 °C
Increasing temperatures above core body temperature
3.1
37 °C
36 °C 32 °C
Sweating 28 °C Blood vessels dilate
Normal core body temperature: 37 °C Blood vessels constrict
34 °C 31 °C
Temperature of hands and feet falls Shivering
Decreasing temperatures below core body temperature
Fig. 3.1.3 How our bodies regulate temperature
F
Homeostasis is the reason dogs pant on a hot day. Unlike humans, dogs do not have sweat glands, so they have to stick out their tongues to control their temperature instead!
