Capillaries
From The School of Biomedical Sciences Wiki
Capillaries are the small branching vessels of the circulatory system. They are the smallest blood vessel in the body and have walls that are only a single endothelial cell thick.
The main function of the capillaries is the exchange of oxygen, waste and nutrients from cell to blood and blood to cell. The capillaries form a bridge between the arterioles and veins of the circulatory system, they recieve oxygenated blood from the arterioles and return deoxygenated blood to the veins[1].
