心血管

In fact the cardiovascular system is not only responsible for delivering blood and oxygen, but also for transporting nutrients, hormones and waste throughout the body. All of these are carried in the blood, of which an average adult has about 5 liters. The heart acts as a pump which circulates the blood through the (capillaries, arteries and veins).

事实上，心血管系统不仅输送血液和氧气，还负责将营养物质激素 和废物输送到全身。所有这些都是以血液为载体，其中成年人的血量为5升，心脏是起到泵的作用，通过毛细血管， 动脉，静脉来循环。

Cardiovascular 心血管

Circulate 循环

capillaries, arteries and veins.

毛细血管 动脉 静脉