英语听力文摘 English Digest 696 氧气有毒么？

Can Oxygen Be Toxic¹?

In order for us to live we must have oxygen, so how can it be bad for us? Today we explain how oxygen can be toxic.

Toxic? Really?

Unbeknown to most people, too much oxygen can be toxic. After several days of breathing nothing but pure oxygen, you’d begin to experience nausea², dizziness, muscle twitches³, and convulsions. You might even die.

Ironically, too much oxygen actually inhibits⁴ ventilation and ends up slowing down the delivery of oxygen to your body’s tissues. Another problem is that certain tissues, like the lining⁵ of the lungs and the walls of the arteries⁶, are very sensitive to oxygen. The cornea is also very sensitive to oxygen; you may have heard of people who have gone blind because, as newborns, the oxygen levels in their incubators were too high.

Oxygen Molecules⁸

Scientists aren’t really sure why oxygen affects the body this way. Some think it has to do with a special form of the oxygen molecule⁷ which bonds with the proteins and membranes⁹ in the lining of the lungs, and ends up destroying them. In other words, with too much oxygen around, your insides begin to oxidize.

氧气有毒吗？

为了我们的生存，我们必须有氧气，所以它怎么会对我们有害呢？今天我们来解释氧气是如何有毒的。

有毒是真的

大多数人都不知道，氧气过多会有毒。几天只呼吸纯氧后，你会开始感到恶心、头晕、肌肉抽搐和抽搐。你甚至可能会死。

具有讽刺意味的是，过多的氧气实际上会抑制通气，最终会减缓氧气向身体组织的输送。另一个问题是，某些组织，如肺的内衬和动脉壁，对氧气非常敏感。角膜对氧气也非常敏感；你可能听说过一些人失明，因为作为新生儿，他们的孵化器中的氧气含量过高。

氧分子

科学家们还不清楚为什么氧气会这样影响身体。一些人认为这与一种特殊形式的氧分子有关，这种氧分子与肺部内层的蛋白质和膜结合，最终破坏了它们。换句话说，氧气过多，你的内部开始氧化。

1 toxic   

adj.有毒的，因中毒引起的

参考例句：

• The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
• There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。

2 nausea   

n.作呕，恶心；极端的憎恶(或厌恶)

参考例句：

• Early pregnancy is often accompanied by nausea.怀孕期常有恶心的现象。
• He experienced nausea after eating octopus.吃了章鱼后他感到恶心。

3 twitches   

n.（使）抽动， （使）颤动， （使）抽搐( twitch的名词复数 )

参考例句：

• No response, just a flutter of flanks and a few ear twitches. 没反应，只有胁腹和耳朵动了几下。 来自互联网
• BCEF(50,100 mg·kg~-1 ) could distinctly increase the head-twitch number in the 5-HTP induced head-twitches test. BCEF50、100mg·kg-1可明显增加5羟色胺酸诱导甩头小鼠的甩头次数。 来自互联网

4 inhibits   

阻止，抑制( inhibit的第三人称单数 )； 使拘束，使尴尬

参考例句：

• A small manufacturing sector inhibits growth in the economy. 制造业规模太小有碍经济增长。
• His bad English inhibits him from speaking freely. 他英语学得不好，这使他不能表达自如。

5 lining   

n.衬里，衬料

参考例句：

• The lining of my coat is torn.我的外套衬里破了。
• Moss makes an attractive lining to wire baskets.用苔藓垫在铁丝篮里很漂亮。

6 arteries   

n.动脉( artery的名词复数 )；干线，要道

参考例句：

• Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
• This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》

7 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

8 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

9 membranes   

n.（动物或植物体内的）薄膜( membrane的名词复数 )；隔膜；（可起防水、防风等作用的）膜状物

参考例句：

• The waste material is placed in cells with permeable membranes. 废液置于有渗透膜的槽中。 来自辞典例句
• The sarcoplasmic reticulum is a system of intracellular membranes. 肌浆网属于细胞内膜系统。 来自辞典例句