General structure

The circulatory system consists of:

  • a system of tubes (arteries, capillaries and veins)
  • a pump (the heart)
  • valves to ensure a one-way flow of blood
Oxygenated blood enters heart via lungs, travels from heart via aorta. Deoxygenated blood travels from upper and lower body back to lungs via vena cava and pulmonary arteries.Systemic circulation between the heart and other organs

Arteries and veins

Arteries carry blood away from the heart towards an organ, while veins carry blood from an organ towards the heart.

This table lists the arteries and veins that are associated with the lungs, liver and kidneys.

OrganTowards organAway from organ
LungPulmonary arteryPulmonary vein
LiverHepatic arteryHepatic vein
KidneyRenal arteryRenal vein