一氧化氮在心血管系统中起着重要的作用，因为它介导血管内皮舒张，这可以缓解血液流经心脏和循环系统的压力。

Nitric oxide is crucial to the cardiovascular system because it signals the inner walls of blood vessels to relax, which facilitates the flow of blood through the heart and circulatory system.

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循环系统把血液输送到全身。该系统包括心脏、动脉、静脉及毛细血管。

The circulatory system carries blood through the body. It includes the heart, arteries, veins and capillaries.

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The circulatory system which we'll talk about in a couple of weeks, the heart, the blood vessels, and the blood work together to form a totally internal function.

例如过几周我们要讲的循环系统,心脏,血管,血液,三者协同工作,形成一个完全在体内发挥作用的体系

耶鲁公开课 - 生物医学工程探索课程节选