We have arteries and we have veins and we also have capillary. So let's begin by focusing on our artery. Now arteries vary in size. The largest artery of our body is our aorter and the smallest one is something called an arterial and we also have different sizes in between. Now by definition an arteries a blood vessel that always carries blood away from the heart and to the cells, the tissues and organs of our body. And most of the time our arteries carry blood that contains oxygen.