英语听力文摘 English Digest 684 心脏的正确位置你知道么

 

Are You Sure Your Heart’s In The Right Place?

On today’s Moment of Science, we’re sure your heart’s in the right place. But where is it exactly?!? CPR classes show how to press on the sternum, in the center of the chest, to stimulate¹ the heart. But then again, hearing the heartbeat is easier on the left.

What Gives?

Anatomically speaking, the heart is pretty much centered in the chest cavity, although it is tilted² to the left, and takes a bit more space from the neighboring left lung than the right.

To understand why the heartbeat’s easier to hear on the left side, we need to know about the four chambers⁴ of the heart.

Top Of The Heart

The atria are the two small chambers at the top of the heart. The two ventricles are the larger, more muscular chambers on the bottom. Because the atria simply pump blood down to the ventricles, they don’t need to be that muscular.

The right ventricle needs to be more bulky, because it pumps blood out to the lungs to get oxygen. But the left ventricle has the most difficult task–pumping blood to the rest of the body–so it’s the most muscular chamber³ of the heart. It’s also closest to the chest wall, while the atria are farther back, tucked under the lungs.

Work That Heart

That means that the left ventricle, the hardest-working chamber of the heart, is not only farthest to the left but also closest to the chest wall. And that’s why it’s so easy to hear your heartbeat on the left, even though the heart is nearly centered in the chest.

你确定你的心在正确的地方吗？

在今天的科学时刻，我们确信你的心在正确的位置。但它到底在哪里？！？心肺复苏课程展示了如何按压胸部中央的胸骨，以刺激心脏。但话说回来，听到心跳在左边更容易。

有什么好处？

从解剖学上讲，心脏基本上位于胸腔的中心，尽管它向左倾斜，并且与相邻的左肺相比，右肺占用的空间稍大。

为了理解为什么心跳在左侧更容易听到，我们需要了解心脏的四个腔室。

心之巅

心房是心脏顶部的两个小腔室。两个心室是底部更大、肌肉更发达的心室。因为心房只是将血液输送到心室，所以它们不需要那么肌肉发达。

右心室需要更大，因为它将血液输送到肺部以获取氧气。但是左心室有最困难的任务——将血液输送到身体的其他部位——所以它是心脏中肌肉最发达的心室。它也离胸壁最近，而心房更靠后，藏在肺部下面。

用心工作

这意味着左心室，心脏最坚硬的工作腔，不仅离左边最远，而且离胸壁最近。这就是为什么在左侧很容易听到心跳的原因，即使心脏几乎位于胸部中央。

1 stimulate   

vt.刺激，使兴奋；激励，使…振奋

参考例句：

• Your encouragement will stimulate me to further efforts.你的鼓励会激发我进一步努力。
• Success will stimulate the people for fresh efforts.成功能鼓舞人们去作新的努力。

2 tilted   

v. 倾斜的

参考例句：

• Suddenly the boat tilted to one side. 小船突然倾向一侧。
• She tilted her chin at him defiantly. 她向他翘起下巴表示挑衅。

3 chamber   

n.房间，寝室；会议厅；议院；会所

参考例句：

• For many,the dentist's surgery remains a torture chamber.对许多人来说，牙医的治疗室一直是间受刑室。
• The chamber was ablaze with light.会议厅里灯火辉煌。

4 chambers   

n.房间( chamber的名词复数 )；（议会的）议院；卧室；会议厅

参考例句：

• The body will be removed into one of the cold storage chambers. 尸体将被移到一个冷冻间里。 来自《简明英汉词典》
• Mr Chambers's readable book concentrates on the middle passage: the time Ransome spent in Russia. Chambers先生的这本值得一看的书重点在中间：Ransome在俄国的那几年。 来自互联网