Blood vessel prevent backflow as a result of a decrease in blood pressure as the blood passes through the circulatory system. There are various kinds of blood vessels: They are roughly grouped as "arterial" and "venous", determined by whether the blood in it is flowing "away from" (arterial) or "toward" (venous) the heart. The term "arterial blood" is nevertheless used to indicate blood high in oxygen, although the pulmonary artery carries "venous blood" and blood flowing in the pulmonary vein is rich in oxygen. This is because they are carrying the blood to and from the lungs, respectively, to be oxygenated. Blood
Experiments in the Revival of Organisms is shown being isolated from a body; four tubes connected are then connected to the organ. Using an apparatus, the heart beats in the same manner as if it were in a living organism. The film then shows a lung in a tray, which is operated by bellows that oxygenate the blood. Following the lung scene, the audience is then shown a heart-lung machine, composed of a pair of diaphragm linear pumps, venous and arterial, exchanging oxygen with a water reservoir. It is then seen supplying a canine head with oxygenated blood. The head is presented with external stimuli, which