An oxygen molecule is absorbed from the alveoli in the lungs into the bloodstream. The passage below describes its journey to a kidney cell where it is used in respiration. Complete the sentences in the passage by writing a suitable word or words on each dotted line.
The oxygen diffuses from the alveoli into the blood flowing through the surrounding .................................................... , which are the smallest blood vessels in the lungs. This oxygenated blood is carried back to the left atrium of the heart via the pulmonary .................................................... .
From the left atrium, the blood passes into the left .................................................... . It is then pumped out of the heart into the largest artery in the body, called the .................................................... .
This artery branches into major blood vessels, including the .................................................... artery, which delivers the oxygenated blood directly to the kidneys.
Once in the kidney tissue, the oxygen diffuses into the cells to act as the final electron acceptor in .................................................... respiration, a process that releases energy in the form of ATP within organelles called .................................................... .
