What is the purpose of capillaries in the circulatory system?

The primary purpose of capillaries in the circulatory system is to permit the exchange of materials between blood and the body’s cells. Capillaries are the smallest blood vessels, and their thin walls facilitate this exchange process. They connect arterioles and venules, forming a vast network that allows oxygen, nutrients, carbon dioxide, hormones, and waste products to pass between the blood and surrounding tissues.

The structure of capillaries is designed for efficient exchange; their walls are just one cell thick, which minimizes the distance for diffusion and ensures that vital substances can move quickly and effectively into and out of cells. This process is crucial for maintaining cellular function and overall homeostasis within the body.