Capillaries are small, thin blood vessels that connect the arteries and the veins. Their thin walls allow oxygen, nutrients, carbon dioxide and waste products to pass to and from the tissue cells.

What is the function of capillaries?

Capillaries, the smallest and most numerous of the blood vessels, form the connection between the vessels that carry blood away from the heart (arteries) and the vessels that return blood to the heart (veins). The primary function of capillaries is the exchange of materials between the blood and tissue cells.

What are the two main jobs of the capillaries?

Capillaries surround body cells and tissues to deliver and absorb oxygen, nutrients, and other substances. The capillaries also connect the branches of arteries and to the branches of veins. The walls of most blood vessels have three distinct layers: the tunica externa, the tunica media, and the tunica intima.