国家地理-2008-07-24 生存危机下的人体反应

In animals, this part of the brain evolved around the time of the dinosaurs¹ before mammals existed. It's hardwired to beat starvation. For three days Jean-Luc has been trapped underground. He hasn't had a morsel² to eat. He doesn't know it, but his brain is changing how his body functions and how he behaves.

There are a couple of different brain centers that graduate feeding behavior as well as hunger. They’re in different parts of the central part of the brain called the hypothalamus. And in that part of the brain you are really driven to seek out food to eat almost anything to try to stop yourself from starving to death.

 To drive Jean-Luc’s search for food his brain first releases a hormone³--orexin. Orexin comes in tiny doses, but it has a profound effect. This hormone makes us more alert, improves our muscle efficiency, making us better hunters. It even sharpens our problem-solving skills.

 For days Jean-Luc scours⁴ the caves. He finds water but nothing to eat. He starts to fear the worst.

 Even if when I had a little hope, I thought obsessively⁵ what would happen over the last few days or the last hours before dying. It was a big question: how I would die--was it going to be cold or hunger or… It was a question that I always had in my head.

 Sure that he's doomed⁶, he records a message. But as hope fades, Jean-Luc’s brain switches strategy to help him survive with no food. With his fuel stores depleted⁷, his body becomes even more efficient. It makes him slow down. Now his muscles use less energy, so do all his internal organs. New cells grow more slowly. Nonessentials—fingernails, toenails, hair—hardly grow at all. Jean-Luc is entering a survival state that evolved to keep starving animals alive until they could get to food.

 This enforced efficiency which kicks in when we're at our limit may have bigger implications. Some say, it could help us all live longer.

1 dinosaurs   

n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西

参考例句：

• The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
• Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》

2 morsel   

n.一口，一点点

参考例句：

• He refused to touch a morsel of the food they had brought.他们拿来的东西他一口也不吃。
• The patient has not had a morsel of food since the morning.从早上起病人一直没有进食。

3 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。

4 scours   

走遍（某地）搜寻（人或物）( scour的第三人称单数 )； （用力）刷； 擦净； 擦亮

参考例句：

• The roasting pan scours better than pot. 烤盘比锅容易擦干净。
• The best scours for UF membrane washing were 0.1%NaOH and 0.5%U10 solution consecutively washing. 0.1%NaOH 和0.5%U10溶液是理想的超滤膜清洗剂。

5 obsessively   

ad.着迷般地，过分地

参考例句：

• Peter was obsessively jealous and his behaviour was driving his wife away. 彼得过分嫉妒的举止令他的妻子想离他而去。
• He's rude to his friends and obsessively jealous. 他对他的朋友很无礼而且嫉妒心重。

6 doomed   

命定的

参考例句：

• The court doomed the accused to a long term of imprisonment. 法庭判处被告长期监禁。
• A country ruled by an iron hand is doomed to suffer. 被铁腕人物统治的国家定会遭受不幸的。

7 depleted   

adj. 枯竭的, 废弃的 动词deplete的过去式和过去分词

参考例句：

• Food supplies were severely depleted. 食物供应已严重不足。
• Both teams were severely depleted by injuries. 两个队都因队员受伤而实力大减。