Capillary

Real World Example

Imagine trying to pass a delicate note through a tiny crack in a door to your friend on the other side. Just like this small opening allows you to exchange messages without opening the whole door, capillaries serve as tiny passages that enable the exchange of gases, nutrients, and waste products between blood and tissues. In both cases, the small size facilitates precise exchanges—your note being the nutrients or gases, the crack being the capillary, and your friend being the body's tissues receiving essential information or substances.