The respiratory and digestive systems provide essential materials that ensure the proper function of cells. The standard function of body cells is in turn necessary for respiratory and gastrointestinal operations. The respiratory system provides oxygen to the cells while the digestive system provides nutrients. The cells need these materials to create energy.
Through respiration, oxygen collects in the lungs and is absorbed into the blood stream. Digestion, on the other hand, breaks down complex molecules into simpler molecules. These molecules are absorbed into the bloodstream. Blood delivers both oxygen and the simpler molecules to the cells. The cells combine the two to produce energy. Thus, the respiratory and digestive systems are connected by the bloodstream. They are also essential in the production of energy for the body.