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Alveolar Capillaries

Last Updated: Jun 23, 2015

The alveolar capillaries are a component in the gas exchange process in the lungs. A capillary wall has about the same thickness as each alveolus wall, which is only one cell thick. The distance between air and blood is about 1/1000th of a millimeter. The oxygen is transported by the red blood cells, which squeeze single file through the pulmonary capillaries. Red cells are packed with hemoglobin,mycontentbreak or red pigment, which attracts the oxygen. Carbon dioxide is diffused in the same way back through the capillaries and alveolar walls to be exhaled. The enormous surface area of the alveoli and the short diffusion distance between alveolar air and capillary blood quickly allows the blood to achieve equilibrium with gases of the alveolar air. This function is further increased by the fact that each alveolus is surrounded by a capillary network so extensive that it forms an almost continuous sheet of blood around each alveolus.