Transcript · English → Chinese
English → Chinese transcript
如果你有医生朋友
，可以试试这个。
问问他们主动脉
瓣是怎么关闭的。记住，
这是那个把血从心脏送出去
的瓣膜。他们会说，
血液被泵出去，减速，
然后当它停下来时，
它开始往回流，
瓣膜就关上了。
这是错的。
如果真是那样，
那么每一次心跳都会有
一部分血液回
漏进心脏，
而且瓣叶会起皱、
折叠错位。
所以，莱奥纳多显然认
真思考过这个问题。
在这之前的好多年，
他观察过水被挤过狭窄
空隙时形成的漩涡，
并意识到这正是
心脏泵血时
发生的情况，
也就是血液通过主
动脉瓣时的情形。
他预言，被
射出的血液会
具有一种“
旋转的冲力”，
会在血液倒流之前，
主动地把瓣膜关上。
他早就预言，
瓦尔萨尔瓦
窦是被特意
塑造成能够
产生涡流的
形状这样就能
以最高效、
而且零渗漏
的方式关闭
主动脉瓣。
以列奥纳多的性格来说，
他亲手制作了
一个玻璃模型，
并往里面抽水循环。
水里放着草籽，
这样他就能把流动动力学
形象化地看到，
这些就是他那些
漂亮的草图，
展示了他所
看到的一切。
难以置信的是，
人们花了整整450年
才证明他是对的。
一位名叫布赖恩·贝尔豪斯的
工程师和他的团队在1969年
做了一个升级版模型，
证实了这些涡流的存在，
还证实了主动脉瓣
在血液射出
尚未结束前就
已经关闭，
正如达·芬奇当年
所理论的那样。
而就在最近几年，
我们已经能够
使用四维流动
心脏磁共
振成像，
这也是我花一部分
时间在做的工作。
在这里你可以看到
达·芬奇在
没有任何现代
技术的情况
下准确预言的那些涡流，
就在将近500年前。
End of transcript · 349 words · machine translated
Original transcript (English)
If you're friends with a doctor, try this. If you're friends with a doctor, try this. Ask them how the aortic valve closes. Ask them how the aortic valve closes. Remember, this is the one leaving the heart.
They will say that blood is pumped out, slows, and then as it stops, They will say that blood is pumped out, slows, and then as it stops, it starts to fall back and the valve shuts. This is wrong. it starts to fall back and the valve shuts. This is wrong. it starts to fall back and the valve shuts. This is wrong.
If that were the case, then with each heartbeat there would be some leaking of If that were the case, then with each heartbeat there would be some leaking of If that were the case, then with each heartbeat there would be some leaking of blood back into the heart and the leaflets would crumple up and fold incorrectly. blood back into the heart and the leaflets would crumple up and fold incorrectly.
blood back into the heart and the leaflets would crumple up and fold incorrectly. So Leonardo clearly thought about this. So Leonardo clearly thought about this. Years earlier he'd watched eddies formed in water that was squeezed through a Years earlier he'd watched eddies formed in water that was squeezed through a
Years earlier he'd watched eddies formed in water that was squeezed through a narrow space and he realized this is what was happening when the heart was pumping narrow space and he realized this is what was happening when the heart was pumping narrow space and he realized this is what was happening when the heart was pumping blood through the aortic valve.
blood through the aortic valve. blood through the aortic valve. He predicted the ejected blood would possess "revolving impetus" He predicted the ejected blood would possess "revolving impetus" that would actively shut the valve before blood flowed backwards.
that would actively shut the valve before blood flowed backwards. that would actively shut the valve before blood flowed backwards. He had predicted the sinus of Valsalva was shaped specifically to create vortices He had predicted the sinus of Valsalva was shaped specifically to create vortices He had predicted the sinus of Valsalva was shaped specifically to create vortices
in order to close the aortic valve in the most efficient way possible with no leak. in order to close the aortic valve in the most efficient way possible with no leak. in order to close the aortic valve in the most efficient way possible with no leak. in order to close the aortic valve in the most efficient way possible with no leak. Leo being Leo,
Leo being Leo, he built a glass model through which he pumped water. he built a glass model through which he pumped water. In the water were grass seeds so that he could visualize the flow dynamics, In the water were grass seeds so that he could visualize the flow dynamics,
In the water were grass seeds so that he could visualize the flow dynamics, and these are his beautiful sketches showing what he saw. Incredibly, it took 450 and these are his beautiful sketches showing what he saw. Incredibly, it took 450 and these are his beautiful sketches showing what he saw. Incredibly, it took 450 years to prove him right.
An engineer called Brian Bellhouse and his team built an updated model in 1969 An engineer called Brian Bellhouse and his team built an updated model in 1969 which confirmed the vortices, and that the aortic valve closes before the ejection of blood has finished, and that the aortic valve closes before the ejection of blood has finished,
just as Leonardo had theorized. just as Leonardo had theorized. just as Leonardo had theorized. And just in the last few years we're able to use 4D flow And just in the last few years we're able to use 4D flow
cardiac magnetic resonance imaging, cardiac magnetic resonance imaging, cardiac magnetic resonance imaging, which is what I spend some of my time doing. which is what I spend some of my time doing.
And here you can see the exact vortices Leonardo da Vinci predicted without any And here you can see the exact vortices Leonardo da Vinci predicted without any modern technology almost 500 years ago. modern technology almost 500 years ago. modern technology almost 500 years ago.
