What is the primary function of capillaries?

The primary function of capillaries is to connect arteries and veins, facilitating the exchange of nutrients, gases, and waste products between the blood and tissues. Capillaries are the smallest and most numerous blood vessels in the body, forming a vast network that allows for efficient diffusion.

Oxygen and nutrients in the blood can easily diffuse through the thin walls of capillaries into surrounding tissues, while carbon dioxide and other metabolic waste products move from the tissues into the blood. This process is essential for maintaining homeostasis and ensuring that cells receive the necessary substances for energy production and other metabolic activities.

Other options do not accurately represent the primary role of capillaries. For instance, while depositing blood to major organs and regulating blood pressure are crucial functions within the circulatory system, these processes are primarily related to larger blood vessels and systems, not the direct action of capillaries themselves. The storage of blood is not a function of capillaries, as they are not designed for holding blood but for facilitating exchange.