Blood requires to be oxygenated and for that reason to avoid the mixing of the two forms or types of blood with different properties and characteristics. As, the blood inside the human body is either in the oxygenated form or it is in the deoxygenated form, while the whole characterizing of the blood medium is based upon the presence of the oxygen,O₂ and carbon dioxide,CO₂ inside it.
While, the lungs are there for the oxygenation of the blood inside the human body, which is comprised of the small air sacs or alveolar bodies for the oxygenation of the blood supplied to it by the pulmonary artery from the right auricle.
As, the blood supplied from all over the body is transported back to the heart through the superior and inferior venacava pouring the deoxygenated form of blood in to the heart.
As the blood remains there for less then a second and goes into the right ventricle carrying it to the pair of lungs through the pulmonary artery.
Inside the lungs the alveoli treats the material present inside the blood medium, which is processed through the process of respiration and oxygen is added to it while the carbon is removed and extracted from the body of the human being.
As, the purified form of blood is sent back to the heart via the pulmonary artery, which pours the blood back into the left auricle.
