Multiple. Arteries, arterioles, cappilaries, veinules, veins.
Blood Vessel Types. Arteries, veins, and capillaries. Arteries carry oxygen rich blood away from the heart & toward the organs. Veins carry oxygen poor blood away from the organs and back to the heart & lungs to get re-oxygenated. The capillaries are the connecting blood vessel that travel between arteries and veins, allowing the blood exchange between the two networks.
Depends. If you mean vasculitis, then rheumatologists. If it's a blocked artery, then it could be a vascular surgeon, cardiologist, interventional radiologist, heart surgeon, etc.