Blood-air barrier
The blood-air barrier refers to the thin layer in the lungs the air-filled space of the air sacs (alveoli) of the blood in the capillaries separates.
The blood-air barrier consists of type I pneumocytes ( type I alveolar epithelial cells), the capillary endothelium and the normally fused basal lamina of these two layers. It enables the diffusion of breathing gases , i.e. the absorption of oxygen into the blood and the release of carbon dioxide into the airways. Their thickness is not uniform, depending on whether the capillary endothelium lies directly on the alveolar epithelium or whether there is still a thin layer of connective tissue in between. On average, the blood-air barrier is (2.2 ± 0.2) μm thick, at its thinnest points it measures only approx. 0.2 μm.
Individual evidence
- ↑ Ulrich Welsch : Sobotta. Textbook histology. Cytology, histology, microscopic anatomy . 2nd, completely revised edition. Urban & Fischer in Elsevier, Munich et al. 2006, ISBN 3-437-44430-1 , p. 327 .