有关于大脑 part 3 Hints: haulage squeeze esophagus centimeters

Everything that's alive and quite a few things that aren't, gives off heat. That's what you are looking at now. Every part of your body is burning up energy and creating heat as it goes about the business of being you. But the hottest bit of you is up here, your brain is burning up more energy than anything else in your body, almost a fifth of all the calories you eat and drink. And it uses up almost the same amount whether you are concentrating on something really difficult or just wondering whether to put the cat out, because day and night, Your brain is challenged with the most difficult task it will ever face, keeping you alive.
Right now for instance, there are quite a few things on your mind, tonight's dinner for example. For starters, your brain is coordinating a major haulage operation.
Even though the route is usually downhill, food doesn't fall from your mouth to your stomach. When your brain tells you to swallow, it triggers waves of muscle contractions. They squeeze things along in your esophagus at around four centimeters per second.

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