Respuesta :
This is because the silica dust and asbestos fibers inhaled will stay in the lungs for a couple of years even after leaving the area of exposure. The dust and fibers will continue invoking immune response (engulfment by macrophages). This response result to production of collagen and extracellular matrix by fibroblasts. This cause formation of nodes in the lungs (due to cell death) and spread from the lungs to other regions (confluence).
The silica dust or asbestos fibers once exposed to the body causes continuous cell death even after preventing further exposure because these tiny particles reach deep inside the lung or digestive tract and cause incurable diseases like silicosis and asbestosis, respectively.
Further Explanation:
Silicosis is a disease caused in humans due to exposure and inhalation of silica dust particles. These particles are small in size and therefore, can reach up to the alveoli, the deepest part of the lungs. When the dust particles rest on the surface of alveoli, they are removed by the action of macrophages. However, due to the presence of free crystalline silica in the dust particles causes the breakdown of macrophages which results in the formation of scar patches on the alveolar surface. A large number of silica particles get excess to the lungs due to their small size on initial exposure. Therefore, even after preventing further exposure, the already reached dust particles continue harming the alveolar surface while destroying the macrophages. This makes the surface less elastic and hence, reduces the gaseous movement through the lungs which lead to decreased breathing.
Asbestos is a mineral that occurs naturally and is resistant to corrosion and heat. It is, therefore, extensively used in the products used for insulation, floor tiles, and cement. These fibers are also useful in the mining industry. The people working in such industries and workplaces are mainly exposed to asbestos fibers. The fibers released in the air are inhaled by the workers and gets trapped forever in their body. Over time, these fibers result in inflammation and scarring in the respiratory tract. The disease caused in humans due to asbestos fiber exposure is asbestosis. It is also a non-curable disease and causes scarring of the lung tissues.
Both silica dust and asbestos fibers are tiny particles which once inhaled by a person are trapped inside the body. Therefore, cause continuous cell death as the disease caused by them are incurable. Although preventions can be taken to lower symptoms, complete removal of these particles from the body is impossible.
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Answer Details:
Grade: High School
Subject: Biology
Chapter: Cancer Biology
Keywords:
Silica dust, asbestos fibers, silicosis, asbestosis, lung, alveoli, scarring, macrophages, mining industry, inflammation, respiratory tract, non-curable disease.
