Oxygen-poor blood refers to blood that has a lower than normal oxygen content. This type of blood is typically returning from the body's tissues and organs, where oxygen has been used up during cellular respiration. The process of oxygenation involves the exchange of oxygen and carbon dioxide in the lungs, where oxygen-poor blood becomes oxygen-rich as it absorbs oxygen from the inhaled air. read more >>

The inferior and superior vena cava bring oxygen-poor blood from the body into the right atrium. The pulmonary artery channels oxygen-poor blood from the right ventricle into the lungs, where oxygen enters the bloodstream. The pulmonary veins bring oxygen-rich blood to the left atrium.read more >>