How do humans and other mammals keep homeostasis of their body temperature?

Humans and other mammals keep their body temperature within just a few degrees of 37 degrees celcius. To achieve homeostasis of body temperature, three components are involved: a receptor, a co-ordinator, and an effector. Example One: Body temperature falls because of a low environmental temperature (e.g. going out in the snow). Receptors in the skin and hypothalamus detect a decrease in blood temperature. Hypothalamus (co-ordinator) signals to several effectors, including blood vessels in the skin, erector pili muscles, skeletal muscles and the body's metabolism. The blood vessels in the skin contract so that blood flow to the skin surface is decreased. This keeps heat inside the body so that it is not lost by conduction and radiation. Erector pili muscles contract and body hair stands up, trapping a layer of warm air close to the skin for insulation. Shivering caused by rapid contraction of skeletal muscles produces heat to warm the body. Additionally the metabolic rate of the body is increased to produce more heat. Result: Rise in body temperature back to 37 degrees celcius. Example Two: Body temperature rises because of a high environmental temperature (e.g. human walking along a tropical beach). Receptors in the hypothalamus detect an inrease in blood temperature. Hypothalamus (co-ordinator) signals to sweat glands (effectors) to produce sweat. Signals from the hypothalamus also result in dilation of blood vessels in the skin so that blood flow to skin surface increased (bringing heat to the surface to be lost from the body), and relaxation of erector pili muscles so that body hair lies flat. Body's metabolic rate also decreases to decrease production of heat. Result: Fall in body temperature back to 37 degrees celcius.