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HL1115 Influences on Health at Work

HL1115 Influences on Health at Work. Occupational lung disorders: asthma, byssinosis, pneumoconiosis, asbestosis, mesothelioma, farmers lung, acute and chronic effects of exposure to toxic fumes. Routes of Entry:. Routes of Entry:. Mechanism vs. Pathway Mechanism is action

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HL1115 Influences on Health at Work

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  1. HL1115 Influences on Health at Work Occupational lung disorders: asthma, byssinosis, pneumoconiosis, asbestosis, mesothelioma, farmers lung, acute and chronic effects of exposure to toxic fumes.

  2. Routes of Entry:

  3. Routes of Entry: Mechanism vs. Pathway • Mechanism is action • Pathway is route of entry We use both terms!

  4. Routes of Entry: Nasal Inhalation

  5. Routes of Entry: Oral Ingestion

  6. Routes of Entry: Dermal (Skin) Absorption Injection

  7. Routes of Entry: • Inhalation • Ingestion • Skin • Absorption • Injection

  8. Routes of Entry: Target Organ vs. Pathway • Target organ is system affected • Pathway is route of entry They don’t have to be the same!

  9. Routes of Entry: • Inhalation is particularly important exposure portal

  10. Routes of Entry:

  11. Inhalation: Air exchange region of lungs is around 300 square ft at rest and about 1000 square ft at full inspiration

  12. Inhalation

  13. Inhalation

  14. Inhalation Absorption Factors • High surface area • Small air/blood distance • Particle size • Solubility

  15. Inhalation Absorption Factors • Concentration • Duration • Respiration Rate

  16. Ingestion Methods • Incidental • Accidental • Deliberate

  17. Ingestion Absorption Factors • Emotional state • Digestive acids/enzymes • Diahhrea/constipation • Gastrointestinal content

  18. Ingestion Absorption Factors • Micro-flora in gut • Metabolite formation • Age • Predisposing factors

  19. Skin Absorption Primary layers: • Epidermis • Dermis • Subcutaneous layer

  20. Skin Absorption Absorption Factors • Disease/injury state • Blood flow, sweat & heat • Skin age • Skin thickness

  21. Skin Injection • Intraperitoneal • Subcutaneous • Intramuscular • Intravenous

  22. Respiratory System • Nasopharynx Region • Tracheobronchial Region • Pulmonary (Alveolar) Region

  23. Respiratory System • Nasopharynx Region: the head region, including the nose, mouth, pharynx, and larynx

  24. Respiratory System • Tracheobronchial Region: includes the trachea, bronchi, and bronchioles

  25. Respiratory System • Pulmonary (Alveolar) Region: comprised of the alveoli; the exchange of oxygen and carbon dioxide through the process of respiration occurs in the alveolar region.

  26. Respiratory System

  27. Particle deposition • Sedimentation

  28. Particle deposition • Diffusion

  29. Particle deposition • Interception

  30. Particle deposition • Impaction

  31. Deposition of particles4-5 mm in respiratory tract 2.5-3 mm in upper respiratory tract 2 mm in URT and lung spaces 1 mm in alveolar spaces

  32. Particulate Sizing Inhalable Particle Mass Thoracic Particle Mass Respirable Particle Mass

  33. Inhalable Particle Mass - hazardous when deposited anywhere in the respiratory tract, 50% cut point 100 mm

  34. Thoracic Particle Mass - hazardous when deposited anywhere in the lung airways or gas exchange region, 50% cut point 10 mm

  35. Respirable Particle Mass - hazardous when deposited in the gas exchange region, 50% cut point 4 mm

  36. Stokes Law An equation relating the terminal settling velocity of a smooth, rigid sphere in a viscous fluid of known density and viscosity to thediameter of the sphere when subjected to a known force field.

  37. Stokes Law

  38. Stokes Law v = settling velocity g = gravitational acceleration, 9.80 m/s2 rs = density of object d =diameter of object rF = density of fluid m =viscosity of fluid

  39. Stokes Law

  40. Reynolds Number laminar flow if Re <500 turbulent flow if Re >500

  41. Stokes Law • settling velocity relates to diameter

  42. Pulmonary function testing(Spirometry)Pulmonary function tests are sensitive indicators of lung disease and are commonly used in the workplace environment HL1115 Influences on Health at Work

  43. HL1115 Influences on Health at Work

  44. HL1115 Influences on Health at Work Common tests • Forced Vital Capacity (FVC) • One Second Forced Expiratory Volume (FEV1) • Ratio of FVC to FEV1 • Peak flow

  45. HL1115 Influences on Health at Work The most common measurements used however are those of FEV1, FVC, and the ratio of these two variables, tests which are highly reproducible within individuals and are easy to administer.

  46. Pulmonary function abnormalities are generally categorized into two patterns: obstructive or restrictive. HL1115 Influences on Health at Work

  47. Obstructive flow impairment,such as observed in asthma bronchitis and emphysema is indicated by a decrease in flow (often indicated by decreased FEV1/FVC ratio). HL1115 Influences on Health at Work

  48. HL1115 Influences on Health at Work

  49. Restrictive flow impairment,such as observed in interstitial lung disease is indicated by a decrease in volume. HL1115 Influences on Health at Work

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