Medically reviewed by Jordana Haber Hazan, MD There are several different kinds of pneumonia, but they all have one thing in common: a full recovery can take weeks. Jump to Key Takeaways. 1. Your ...

What are AMs? The lungs consist of thin-walled air sacs called alveoli. Gas exchange occurs between alveolar air and capillaries within thin layers of interstitial tissue, which are micrometers thick.