We have the systemic circulation and we have the pulmonary circulation. Systemic circulation simply means we carry the oxygenated blood from the heart into the tissues and then we take the de oxygenated blood from the tissues and bring it back to our heart. But pulmonary circulation means we take that deoxian blood from the heart and we move it into the lungs and then we oxygenate our blood in the lungs and we bring the oxygen blood back into the heart and we'll discuss these two systems in more detail towards the end of the lecture. Now there are two types of blood vessels that are found inside our body. We have a blood vessel that carries blood away from the heart and this is known as an artery. So by definition an artery is a blood vessel that always carries our blood away from the heart.