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formaldehyde and vinyl acetate forms tumors in rat

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Unformatted text preview: f fluid (humidify the air) - High surface area, high blood flow, thin membrane - Susceptible to absorption and toxicity! - Formaldehyde and vinyl acetate forms tumors in rat nasal cavities different toxic stuff senstive to corrosive agents, (e.g. HCl) dissolves into aq. mucous, beomces acid 3. Respiratory System: “Pulmonary Route” Lower Airways (alveolus/alveoli) allow for gas exchange (passive diffusion) Protective mechanisms macrophages /phagocytosis of particulate matter/debris (can trap particulate which remains) Function: Gas exchange! High blood flow, thin membrane Also depends on solubility, Small particulate can travel down (SIZE!) Dissolve in fluid, solubility influences Gases diffuse across membrane, dependant on their blood-to-gas partition coefficient Equilibrium dependant High blood flow maintains favorable equilibrium Transporters also present 3. Respiratory System: “Pulmonary Route” Characteristics favouring absorption: A. Single celled lipoidal membrane Type 1 pneumocytes very thin B. Large surface area-expansion of lungs, many aveoli C. Large blood supply (pulmonary circulation) D. Phagocytosis and migration (asbestosis carcinogenesis) Toxicity through the pulmonary route will depend on get down to lower levels of lungs - Particulate size and volatility - Ability to diffuse cross into blood stream - Affinity for transporters protein transporters to carry it away Asbestos Toxicity Small Silicate fibers Good electrical and regular insulation Fire resistant, chemical resistant Good tensile strength Different forms have metals in their composition Mg3(Si2O5)(OH)4 or Fe7Si8O22(OH)2 Asbestos Toxicity Iron on some can produce toxicity through ROS production Fenton reaction Also get ingested by Phagocytic Macrophages Will cross the membrane into the tissues by this method Text Asbestos Toxicity Local inflammation, production of ROS, degredative enzymes Prolonged inflammatory response Cell repair (collagen) and proliferation (scar tissue, function) Asbestosis and possibly Cancer...
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This document was uploaded on 04/07/2014.

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