Blood

Blood supports cellular machinery by delivering life-sustaining materials and removing disruptive waste. Blood carries absorbed nutrients throughout the body. Red blood cells transport oxygen and help remove carbon dioxide. Red blood cells carry oxygen to every cell in the body. The bloodstream is the route through which nutrients move toward their final destination in the body. Absorbed material enters the bloodstream before it becomes integrated into the body. Eating allows nutrients to enter the bloodstream. White blood cells act as the body's immune defense against pathogens and disease. Blood removes waste products, particularly carbon dioxide, from cells. Tobacco's systemic harm to all organs is mediated through its effects on blood. Blood is essential to bodily life because it delivers needed materials to cells and removes waste.