6/10/2023 0 Comments Pool corruption in file area17 So rapid is this translocation that it is thought not to involve phagocytes, although interstitial macrophages are undoubtedly important in continuing the transportation of dust to the nodes. 14, 15, 16 Some of this is transported within hours to the hilar lymph nodes. Some free dust enters through the bronchus-associated lymphoid tissue 11, 12 and some is taken up by, or pierces, the alveolar epithelium ( Fig. Only a small fraction of the inhaled dust gains access to the interstitium, a necessary step if it is to cause pneumoconiosis. ![]() Some minerals, notably chrysotile asbestos, undergo slow physicochemical dissolution in the lungs. 13 Long asbestos fibres present a particular problem to macrophage clearance. 12 This interconnection is probably the route utilised by circulating macrophages clearing other parts of the body of endogenous or exogenous particulate matter via the lung. The airway and interstitial routes interconnect at the bronchiolar level 11 where some dust-laden macrophages leave the interstitium for the air space. ![]() Alveolar clearance is largely effected by macrophages, principally via the airways to the pharynx but also via lymphatics to the regional lymph nodes. ![]() Only dust that reaches the alveoli is liable to cause pneumoconiosis and much of this is also removed, but the clearance rate here is much slower: many coalminers continue to expectorate mine dust years after retirement. Inhaled dust that settles in the conductive airways is removed within a day or two by ciliary action.
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