Document BRoazvdoKG9m8zgbaLBgXODYX

the synthetic libers of glass wool apparently are too inflexible to pus easily throwrh the nose, pharynx, trachea and bronchi and celdoa roach tha terminal bronchioles and alveoli. Inhaled particulate natter cartes to rest throughout the terminal air spaces (alveolar duct, atria, alveoli) th all ports of the luaae; inhaled asbestos fibers are first retained in the respiratory bronchioles. These very antall tube* are immediately distil to bronchioles lined 07 ciliated epitheiiua. their erro essen tial lining' is * lor cuboidal type of epithaliun but, as their name Implies, they actually function in respiration through Lateral alreoli given off &e pouches along their valla. Either these pouches, or the abrupt change in the character of tha lining epithelium, or the decrease in diameter nf the tube, or perhaps the combination of all three factors is responsible for local retention of the inhaled fiber* Only after asbestos!s is veil established are appreciable numbers of fi bers carried into the sore peripheral air spaces. 6. Rata of Tissue Reaction to Asbestos Pibera Tha rate of tissue reaction to asbestos la touch sore rapid than to an active dust like quart*. Evidences of tissue response appear as soon a* fibers nave localised in sufficient concentration in specific rtu. In rate receiving asbes tos fibers by intratracheal injection this evidence is risible us early as t*o week* after infection! fer quarts dust, th* latent period sd^it be t-ro ro-.ttw or wore. Th* beiueviar of ths tissue reaction to inhaled dust ,\ftr the tcrairutioa of exposure is not ths ia* in' silicceia as in asbestosis. In silicosis, the young nodule-s bscccsa Larttrj in asbestoeis, young ecar tissue, t-hat coy.have formed,con tracts send becomes ear dense but the area, of icrolTeoent decreases in site. If exposure to asbestos dust is tsrdmted after a brief period, the recently-inhaled