Which one of the following arteries supplies blood to the human heart muscle?

Correct — C, Coronary artery. The heart pumps blood through its chambers but cannot feed its own muscle from the blood passing inside them; the myocardium has its own supply, delivered by the right and left coronary arteries, which arise from the aorta immediately above the aortic valve and run over the surface of the heart in the coronary sulcus. Narrowing of these vessels by atherosclerosis is what produces angina, and their blockage is what causes a heart attack, because the muscle downstream is cut off from oxygen.

• (a)Pulmonary artery — It carries deoxygenated blood from the right ventricle to the lungs. It is the one artery in the body that carries deoxygenated blood, and it supplies no cardiac muscle.
• (b)Renal artery — A branch of the abdominal aorta supplying the kidney. Its share of cardiac output is large, but none of it goes to the heart wall.
• (d)Hepatic artery — Supplies the liver with oxygenated blood, alongside the much larger flow the liver receives through the hepatic portal vein. Nothing to do with the myocardium.

The heart wall is thick muscle, and diffusion from the blood inside the chambers is nowhere near enough to keep it alive. The coronary circulation solves this: the right and left coronary arteries branch from the ascending aorta, spread across the heart in the grooves between chambers, and drain through cardiac veins into the coronary sinus and so into the right atrium. Since coronary flow is greatest during diastole, when the relaxed muscle is no longer squeezing its own vessels shut, anything that shortens diastole strains the supply.

Each distractor names an artery by the organ it serves, and the pattern makes the item easy once noticed: renal to the kidney, hepatic to the liver, pulmonary to the lungs. 'Coronary' comes from the Latin for a crown, describing the way these vessels encircle the heart — so the name itself carries the answer. Learning arteries by the root of their name is worth more in an examination than memorising a branching diagram.

• The right and left coronary arteries arise from the ascending aorta just above the aortic valve.
• Coronary blood flow is highest during diastole, when the heart muscle is relaxed.
• Cardiac veins drain into the coronary sinus, which empties into the right atrium.
• The pulmonary artery is the only artery carrying deoxygenated blood, and it goes to the lungs.
• Blockage of a coronary artery starves the muscle downstream of oxygen and causes myocardial infarction.

• Assuming the heart is nourished by the blood inside its chambers.
• Reading 'pulmonary' as the heart's own vessel because it leaves the heart directly.
• Forgetting that the pulmonary artery is the exception to 'arteries carry oxygenated blood'.

A single-fact recall item that is really a vocabulary test — each option is an artery named after the organ it feeds.

• practice — not a real PYQ

  Which one of the following blood vessels carries deoxygenated blood?

  • (a)Pulmonary vein
  • (b)Pulmonary artery
  • (c)Aorta
  • (d)Coronary artery

  Answer(b) Pulmonary artery — it carries deoxygenated blood from the right ventricle to the lungs, the reverse of the usual artery-vein rule.

• practice — not a real PYQ

  Blood from the cardiac veins is collected by the coronary sinus and delivered into the

  • (a)left atrium
  • (b)right atrium
  • (c)left ventricle
  • (d)pulmonary vein

  Answer(b) right atrium — the coronary sinus opens into the right atrium alongside the two venae cavae.