实际上你体内的部分血液有时是呈紫色的。一种叫血红蛋白的物质使血液呈色。血液的颜色由血红蛋白中含氧量的多少决定。血液流经肺部时,通过你吸入的空气获得氧气,便呈鲜红色。血液循环时,失掉氧气,便呈深紫红色。如果你看一下自己的手腕 In fact, part of your body’s blood is sometimes purple. A substance called hemoglobin makes blood color. The color of the blood is determined by the amount of oxygen in the hemoglobin. As the blood flows through the lungs, oxygen is obtained through the air you breathe and it is bright red. When the blood is circulated, it is dark purple when it loses oxygen. If you look at your wrist