Design—‘Man Computerised Thermostat’ A kiss of her lips may make him feel hot all over and reduce her to a quivering pile of goose bumps, but inside they are both snuggly warm—constantly warm in fact. To achieve this constant warmth, which has enabled man to cope with and conquer extremes such as a hot Sahara wind or a cold Arctic blizzard, man possesses a complicated temperature control system. It is in reality an automatic, computerised thermostat which works day and night to keep man's body at approximately 36.8 C or 98.4 F. A tiny device which knows how hot you 'should be' is located inside your brain, within a gland known as the hypothalamus. It sends a regular signal about your 'ideal' temperature to another part of the brain which compares the temperature you should be, with the messages coming back from your body about how warm you actually are. If your body is found to be too hot, then an urgent message is sent to yet another body control centre in the brain. This new centre emits a command for the body to start sweating. Water begins to pass onto the surface of the skin, take heat from the body, and evaporate. At the same time your body was commanded to sweat, a second message to expand the blood vessels was sent out. This brings the over-heated blood closer to the skin. You may start to look a little redder, but the heat from your blood is now lost through the skin to the evaporating water. You start to cool down. However if the temperature comparison centre decides you are too cold, messages are sent out to shrink the blood vessels. This brings the blood away from the cold skin. At the same time the muscles are instructed to vibrate to generate warmth. As a result of both these actions you may go pale or even blue and start to shiver, but you begin to warm up. All this and you didn't even have to think about it. Now if you try to construct a similar automatic system to maintain a large shopping centre at the same temperature throughout, you will find it an elaborate and expensive task. Yet, a shopping centre is nowhere near as complicated as a body. For any person to believe that the human temperature control system which works so consistently and involves such complex engineering techniques is a product of an accidental process called evolution, means they are simply ignoring every discovery we have made to date about the science of engineering construction.
|
