The Brain's Role in Motivation
Regulation of body temperature, specific metabolic processes, and other autonomic activities all take place in the brain's hypothalamus region, which also determines blood temperature by way of sensors. These sensors are additionally present inside the mouth, skin, spinal cord, and brain, allowing you to differentiate between hot and cold.
Setting the Thermostat
The anterior, or frontal, portion of the brain is responsible for making sure body temperature remains consistently normal by following a process similar to that of a thermostat. Existing temperature is “read” by sensors and compared to what the normal temperature should be. If the readout turns up an irregularity, specific physiological adjustments will attempt to correct the problem by producing sweat when hot and shivers when cold. In addition, external behavioral adjustments may be prompted, for example, covering up with a blanket when you're cold and tossing the blanket to the side when you're warm.
Although both physiological and behavioral adjustments occur in the hypothalamus, the differences between them are as follows:
Willful acts of selfishness
Drive elicits the response
External conditions are influenced
Housed in the lateral area of the hypothalamus
Uncontrollable physical acts
Need elicits the response
Internal conditions are influenced
Housed in the preoptic area of the hypothalamus
Behavioral and physiological adjustments, as different as they are, work together toward the shared goal of regulating the body's temperature, a process necessary to survival. Temperatures too high above or too far below the norm of 98.6° Fahrenheit (F) must be treated immediately, otherwise organs may become permanently damaged or death may result.
Hypothermia (body temperature below the norm) must be treated when temperature drops below 95°F, and becomes fatal when it drops below 90°F. Fever is when body temperature rises above normal, but doesn't become much of a concern until it reaches at least 100°F.
Severe weather conditions when not guarded against can cause the body to go into shock. For example, Alaska's lowest average temperature during winter (between December and February) is –15.7°F. A person cannot simply walk outside with only one layer of clothing and a heavy jacket without experiencing instant frostbite and symptoms of hypothermic shock.
In contrast, Arizona's climate can reach temperatures as high as 120°F, so if a person takes a day trip to the middle of the desert with only a short supply of water, the body's ability to keep cool is dominated by extreme external temperatures that cause it to “overheat” and suffer from heat stroke. Drastic irregularities in body temperature result in various degrees of physical decline.
When the body reaches certain degrees of temperature, specific reactions are experienced as shown here (temperatures are measured in Fahrenheit):
82.7° = muscle failure
91.4° = unconsciousness
107.6° = breakdown of central nervous system
111.2° = death