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.
alveoli tiny air sacs at the end of the bronchioles tiny branches of air tubes in the lungs the alveoli are where the lungs and the bloodstream exchange carbon dioxide and oxygen carbon dioxide in the blood passes into the lungs through the alveolioxygen in the lungs passes through the alveoli into the bloodnih national cancer institutehe alveoli are where the lungs and the bloodstream exchange carbon dioxide and oxygen carbon dioxide in the blood passes into the lungs through the alveoli oxygen in the lungs passes through the alveoli into the blood nih national cancer institute