What are capillaries known for?

Capillaries are known for being the smallest blood vessels in the circulatory system. Their primary role is to facilitate the exchange of oxygen, carbon dioxide, nutrients, and waste products between blood and surrounding tissues. The thin walls of capillaries consist of a single layer of endothelial cells, which allows for efficient diffusion of these substances. Their small diameter enables them to reach almost every cell in the body, thereby playing a crucial role in maintaining homeostasis and ensuring that tissues receive adequate supplies of oxygen and nutrients while removing waste products.

While larger blood vessels, such as arteries and veins, are responsible for transporting blood to and from the heart, capillaries function at the microcirculation level where the real exchange occurs. Understanding the unique characteristics of capillaries is vital for grasping the overall functioning of the vascular system.