ABSTRACT
The objective of this chapter is to provide the reader with the tools for best understanding the content from past and future publications regarding asbestos burden.
3.1 RESPIRATORY SYSTEM AND WHY IT IS VULNERABLE TO INHALED DUST
To appreciate the signi“cance of asbestos in body tissues, it is “rst relevant to understand how it got there and the normal functioning of the major portal of entry for dust into the body-the respiratory system. The design of the respiratory system has evolved into highly functional anatomical regions. The upper airways are designed to warm, moisten, and “lter the incoming air. These can be thought of primarily as conducting tubes or conduits for two-directional air¸ow. In the ideal situation,
CONTENTS
3.1 Respiratory System and Why It Is Vulnerable to Inhaled Dust ............................................. 49 3.2 Dust Elimination from the Lung ............................................................................................ 52 3.3 Dust Overloading and the Impact on the Respiratory Tract ................................................... 56 3.4 Relocation of Particulates from the Lung via the Lymphatics ............................................... 57 3.5 Morphological Features of Asbestos That Determine Its Potential for Inhalation ................ 59 3.6 Ferruginous Bodies in Tissue .................................................................................................65 3.7 Destructive Testing Methods Used in Sampling Tissue and Fluids for Asbestos
Bodies and Uncoated Asbestos Fibers ....................................................................................69 3.8 Instrumentation Use in Tissue Analysis for Asbestos ............................................................ 71 3.9 Usefulness of Sputum and Lavage as Indicators of Past Asbestos Exposure ......................... 72 3.10 Asbestos Body Burden in Exposed and General Populations ................................................ 76 3.11 Uncoated Asbestos Fibers in Occupationally Exposed Individuals and in Lung Tissue
from the General Population .................................................................................................. 78 3.12 Exposure from Asbestos as a Component of Other Minerals ................................................86 3.13 Asbestos in Extrapulmonary Sites ..........................................................................................87 3.14 Fiber Lengths and the Relationship to Pathogenicity .............................................................92 3.15 Conclusion ..............................................................................................................................97 References ........................................................................................................................................98
