Blood capillaries are made of

The walls of capillaries are made up of a thin cell layer called endothelium that's surrounded by another thin layer called a basement membrane.Each artery and vein consists of three layers: an inner lining of squamous endothelium, the tunica intima, a middle layer of smooth muscle and elastic fibres, the tunica media, and an external layer of fibrous connective tissue with collagen fibres, the tunica externa.