1, the airway (the channel for transmitting gas) of the lungs is like an inverted tree. The main trunk is the trachea, from which many branches are issued, the thinnest branch is called the fine bronchus. The fine bronchioles are divided into clusters of air sacs called alveoli. Each such small air sac (alveoli) is surrounded by tiny blood vessels (capillaries). 2. The normal lung is an elastic, spongy organ made up of many of these air sacs. The tissue that connects and supports these small air sacs is called the interstitium. Imagine a barrel filled with balloons, the balloons are the alveoli or air sacs, the place where the balloons touch each other represents the “interstitium”. 3, the oxygen in the outside air through the airway to the alveoli, and then through the “gap” between the alveoli and capillaries (the so-called interstitial lung) into the blood, while waste products such as carbon dioxide also leave the blood through this gap in the opposite direction, and out of the body, the number of breaths per minute for normal newborns is generally 40 ~ 44 times The normal respiratory rate for newborns is generally 40 to 44 times per minute, while for adults it is 16 to 20 times per minute, and the respiratory rate will increase if there is emotional excitement or if there is inflammation in the body leading to fever.