What is the difference between pulmonary vein and systemic vein

The systemic vein carries oxygenated blood from the heart around the body then carries the deoxygenated blood from the body back to the heart. The blood leaves the left ventricle of the heart via an artery called the aorta, it then travels around the whole body where oxygen is exchanged for carbon dioxide at respiring tissues. Deoxygenated blood is transported back to the heart via a vein called the vena cava.

The pulmonary vein transports blood between the heart and the lungs. The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs. The blood is oxygenated in the lungs where carbon dioxide is exchanged for oxygen. The pulmonary veins then carries the blood back to the heart to be pumped round the body via the systemic vein.