Alveolus

Real World Example

Imagine trying to pass a note to someone across a crowded room without getting up from your seat. This is similar to how alveoli work in your lungs, facilitating the exchange of gases without direct movement. Just as you might pass the note through a series of people, the alveoli serve as tiny, thin-walled sacs that allow oxygen to pass into the blood and carbon dioxide to be passed back to the lungs for exhalation, efficiently exchanging gases in a confined space.