The air is warmed up before passing down the windpipe, where it's divided at the bottom between two airways called bronchi that lead to either lung.
空气在进入气管前被加热了，在气管的底部分成两个导气管通向每一侧的肺，这两人分支被叫做支气管。
2
The bronchi supply air and pulmonary arteriessupply blood to the lungs. Together they take in air from theatmosphere, oxygenate the blood, and excrete the carbon dioxide backout of the body.
Within the lungs, the mucus-lined bronchi split like the branches of a tree into tens of thousands of ever smaller tubes (bronchioles), which connect to tiny sacs called alveoli.