Blood group antigens are carbohydrates that are attached to proteins or lipids. An antigen is a substance foreign to the body that causes an immune response. An immune response occurs when antibodies, which are proteins in your immune system, are summoned to attack an antigen.
Blood that reaches the lungs travels throughout a network of small blood vessels, where oxygen moves into the blood and carbon dioxide moves out of the blood, according to the National Heart, Lung and Blood Institute.
So if you eat something bad and it gets into the blood stream via the intestines, where does the blood flow next? it would make sense for it to go to the liver first and the kidneys to get rid of the nastys first. Also where does the blood flow after the lungs, so if you smoke which organ receives the poisonous blood first ? Well, the lungs are the organs that receive most of the toxins. However blood from the lungs get sent back to the heart. In essence there are two sides of the heart. The left side receives deoxygenated blood, and pumps it to the lungs to be oxygenated. The right side receives oxygenated blood from the lungs, and pumps it out to the rest of the body.