O-Level Transport in Humans: worked solution

Question

A patient can undergo an operation known as a coronary bypass, in which a blood vessel is removed from elsewhere in the patient's body and used to route blood past the narrowed sections, so that the heart muscle receives an adequate blood supply. Give reasons why the vessel taken from another region of the body ought to be an artery rather than a vein.

Blood carried in/near the heart's coronary supply is at high pressure. An artery has a thick, muscular and elastic wall able to withstand this high pressure without bursting. A vein has a much thinner wall and contains valves, so it could burst under the high pressure or its valves would obstruct/impede the blood flow.