These surround the tiny air sacs?

The tiny air sacs in the lungs are called alveoli. They are surrounded by a network of capillaries, which facilitate the exchange of oxygen and carbon dioxide between the air in the alveoli and the blood. This process is crucial for respiration, as it allows oxygen to enter the bloodstream while removing carbon dioxide from the body. The structure of the alveoli, along with their extensive surface area, maximizes this gas exchange efficiency.