Read the summary and the most important questions on TOX20303

• College 1 + 2

  This is a preview. There are 64 more flashcards available for chapter 05/09/2017
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• Rachel Carson 'Silent Spring' (boek) 1962

  Alles was dood gegaan en het gebruik van DDT was uit de hand gelopen. Silent spring niet veel vogels en insecten...
  
  challenged the notion that man was destined to control nature 

• Exposure assessment: route & site of exposure

  • Gastrointestinal tract (oral)
    
  • lungs (inhalation)
  • skin (dermal)
  • injections

• Exposure assessment: duration and frequency

  Acute: <24 hours, single dose 
  subacute: 1 month or less
  subchronic: 1-3 months 
  chronic: >3
  
  effect varies with dose & exposure regimen 

• Calculate if actual exposure is safe: (margin of safety)

  
  
  Margin of safety 
  
  
  exception: initiating genotoxic carcinogens: only risk assessment (no safety, priority setting)

• Oxidative stress: catalyses Haber-weiss reaction

  Increases the impact of superoxide anions O2 *- and H2O2 by the formation of reactive hydroxyl radicals *OH
  
  'makes it more toxic'

• College 3 + 4

  This is a preview. There are 30 more flashcards available for chapter 06/09/2017
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• Absorption: passing cell membranes via

  • Phospholipid
    
  • intergral proteins
  • cholesterol 
  • ion channel 
  • ligand 

• Passive transport is influenced by:

  - Water solubility:
  
        Hydrophobic chemicals --> passive diffusion
        Hydrophilic chemicals --> passive filtration (aqua pores)
  
  - Ionization:
  
         Low pH (< pka) --> chemical in non-ionized form --> chemical is taken up in stomach
         High pH (> pka) --> chemical in ionized form --> chemical is taken up in small intestine
  
  - Blood flow: if molecules are not taken away by bloodflow
         
         Concentration of the chemical = concentration blood

• Uneven distribution of a chemical

  Toxicity in a specific tissue: water soluble chemical + albumin --> stay in fat tissue

• Blood brain barrier

  Active transport needed for the uptake of molecules in the brain:
  - Thight junctions
  - No fenestrea
  - Low protein content
  - ATP is needed

• College 5 + 6

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• Not water soluble chemicals

  Need biotransformation in order to be excreted via urine/bile