Flashcards in Toxicology Exam 2 Deck (21):
What are the four routes of exposure?
Absorption, Dermal, Inhalation and Injection
What are the steps of exposure?
Exposure - Delivery - Reaction - Dysfunction - Repair or Failure to repair
What is first pass elimination/ pre systemic elimination?
Where chemicals are redirected away from target organs and toxicity is successfully prevented
What does the term absorption refer to?
Putting chemicals into systemic circulation
What factors influence whether or not a chemical/toxicant is absorbed?
Concentration, Surface area of exposure, characteristics of epithereal layer where absorbed
What is the most important chemical property influencing absorption?
Lipophilic aka lipid soluble/ nonpolar/ hydrophobic
Properties of hydrophilic molecules are what?
Water soluble, charged aka polar molecules, polar with polar, water mixes with polar
Properties of hydrophobic molecules?
Non water soluble, uncharged molecules, nonpolar mixes with nonpolar, (lipids are an example)
How to mix polar and nonpolar?
What is passive transport?
Diffusion from high to low concentration where no energy is required (no ATP necessary)
What is facilitated diffusion?
Channels through membrane that allow diffusion down the gradient from high to low concentration (no energy or ATP required)
What is active transport?
Transport up gradient low to high concentration (energy and ATP required)
How do most toxicants cross the membrane?
Rate of diffusion depends on what three things?
Lipid solubility, Molecular size, PKA
What is PC and how is it measured?
Partition coefficient and a measure of the substance in a lipid over an aqueous solution
PC of 10 = ?
PC 0.1 = ?
Describe molecular size?
Molecular weight of less than 600 and hydrophilic enter via aqueous pores while larger hydrophobic molecules diffuse across the lipid domain
pH where the toxin is 50% charged and 50% uncharged and it mimics he pH scale of 0-14
What are examples of specialized barriers for preventing the transport of harmful agents to sensitive organs?
Blood brain barrier, placental, blood testes, oocytes