Angela is a serious basketball player, but lately she has been struggling. First, her legs started getting tired halfway through practice. Next, her bones started aching. This week, she feels like she can’t even take a full breath.

Angela goes to see Dr. Chao. “I feel like my whole body is falling apart. How can there be so many different things going wrong with me at the same time?” Angela asks. Dr. Chao does a physical exam and asks Angela to take a few deep breaths. “Actually,” the doctor responds, “there’s only one small thing wrong with your lungs. Fortunately, there is a medicine that will improve all your symptoms right away.”

How can a problem in Angela’s lungs cause problems all over her body?