英语阅读

听力入门英语演讲VOA慢速英语美文听力教程英语新闻名校课程听力节目影视听力英语视频

常识:我们的心脏是如何工作的?

kira86 于2008-07-30发布 l 已有人浏览
增大字体 减小字体
迅雷专用高速下载 How the Heart WorksThis is the VOA Special English Health Report. We talked last week about t
    小E英语欢迎您,请点击播放按钮开始播放……


迅雷专用高速下载

How the Heart Works

This is the VOA Special English Health Report.

We talked last week about the life of famed heart doctor Michael DeBakey. He died this month at age ninety-nine.

知识扩展:Michael DeBakey 在他心脏外科医生的职业生涯中进行了6万多起心脏手术。他的病人中包括美国总统乔治·肯尼迪、林登·约翰逊 、理查德·尼克松,以及俄罗斯总统鲍里斯·叶利钦和伊朗国王。

DeBakey医生于今年7月11日死于德克萨斯的休斯顿,离他100岁生日还有两个月。在他1931年还是名医科学生时,就发明了滚子泵。多年以后,它用于了心脏手术时的血液供应。滚子泵成为了心肺机的一个关键部件。这种机器将富氧血传输至大脑以及其他器官,这样医生就能对心脏进行手术了。

Michael DeBakey是开心外科手术的先驱,这种手术挽救了无数人的生命,该名称的意思是胸腔是打开的并在心脏上进行外科手术。医生可能会打开心脏,也可能不会。Michael DeBakey于1908年9月7日出生于路易斯安那的查尔斯湖,其的父母均是来自黎巴嫩的移民。

Today, we talk about the object of his work. The heart is a complex organ that starts beating a few weeks after conception. At this point the heart is a tube. In the coming days, it grows and bends into the shape of the heart.

Later, it divides into four parts. As the heart beats, it pumps blood through these chambers and the blood vessels in the body. The body is estimated to have at least ninety-six thousand kilometers of blood vessels.

That is about the same as two and a half times around the Earth. But blood goes the distance in about twenty seconds on its way back to the heart. Each day the heart pumps about eight thousand liters of blood.

The blood feeds the brain and other organs with oxygen and nutrients. It also carries away carbon dioxide and other waste.

The heart pumps by expanding and contracting of muscle. In a healthy adult, the heart beats an average of seventy-two times a minute -- about one hundred thousand times a day.

A healthy adult heart is about the size of two fists and looks like a piece of red meat. But in overweight people, it can look yellow because of fat.

Rates of heart disease started growing sharply in the second half of the twentieth century. As machines did more and more work, people did less and less. Not only did physical activity decrease, but people started eating more and more processed foods.

Experts say a diet low in fats and high in fruits, vegetables, proteins and whole grains may help reduce the risk of heart disease. At least thirty minutes a day of physical activity, enough to work up a sweat, can also help. Also important to good health is a good night's sleep.

Cardiovascular disease is caused by disorders of the heart and blood vessels. It includes heart attacks, strokes and high blood pressure. The World Health Organization says there are three major causes: tobacco use, physical inactivity and an unhealthy diet.

The W.H.O. says cardiovascular disease is the world's leading cause of death. And it is predicted to remain that way unless more action is taken. Experts estimate that it could kill twenty million people a year by twenty fifteen. An estimated seventeen and a half million people died in the year two thousand five. Around eighty percent of them died in low- and middle-income countries.

And that's the VOA Special English Health Report, written by Caty Weaver. For more health news, go to en8848.com. I'm Steve Ember.

 1 2 下一页

分享到

添加到收藏

VOA慢速排行