How do we regulate body temperature?

Homeostasis, the regulation of stable body conditions, includes control of body temperature. We function efficiently at 37 degrees celsius, as our proteins and enzymes work best at this temperature. 

We can sweat and shiver, and our blood vessels can dilate or constrict. The hairs on our skin can also become erect in order to trap an insulating layer of air on top of our skin. 

Sweating through our sweat glands increases as we become hotter. It is the evaporation of the sweat off our skin that cools us down, as the sweat takes some of the heat with it. Vasodilation, the widening of surface blood vessels, means some of that heat escapes through our skin as well, cooling down our blood. 

Shivering, acted out by our muscles contracting rapidly, requires respiration. This releases heat, with the end result of warming us up. Vasoconstriction, the narrowing of blood vessels, means less heat is released from our blood and is conserved. This allows the important inner organs to stay warm.