What role do capillaries play in the circulatory system?

Capillaries play a crucial role in the circulatory system by serving as the sites of exchange between the blood and the body’s tissues. These tiny blood vessels connect arterioles, which carry blood away from the heart, to venules, which collect blood returning to the heart. The walls of capillaries are extremely thin, allowing for the efficient transfer of nutrients, gases (such as oxygen and carbon dioxide), and waste products between the blood and surrounding cells. This exchange is vital for maintaining the metabolic needs of tissues and ensuring overall homeostasis in the body.

While capillaries do connect arteries to veins and collect blood leaving organs, their primary function is the direct transport of blood through organs and tissues to facilitate exchange processes. This distinctive role underscores their importance in the overall functionality of the circulatory system.