Oxygen is transported throughout the body via the cardiovascular system, according to the National Register of Personal Trainers, or NRPT. The lungs, blood, heart and blood vessels work together to carry oxygen around the body.
Air first enters the body through the nose or mouth and then goes into the larynx, trachea and the lungs, explains the NRPT. Air passes through bronchial tubes in the lungs until it reaches the alveoli, tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place. The alveoli enable the oxygen to be transferred into the blood. Once it is in the blood, transportation of oxygen around the body begins. Only a small amount of oxygen is transported in the plasma of the blood because oxygen does not dissolve easily in water. The rest of the oxygen is transported after combining with the hemoglobin in red blood cells.
The NRPT notes that the heart is a vital organ for moving oxygen around the body, and it pumps approximately 70 times each minute. It needs to beat continuously to push the oxygen and nutrients that the body needs. The heart works with the arteries, the network of blood vessels that weave between all parts of the body, to accomplish this. Blood passes through the arteries, which are elastic and expand when the heart pumps blood. Oxygen is thus pushed into organs as the blood flows. The muscles in the arteries' walls contract when the heart relaxes to push the blood.