Toxicology Exam 2 Bonus Questions Flashcards
What is the environment?
- Air, water, soil
- Biota
- Space where we live
Environmental toxicology
A multidisciplinary field of science concerned with the study of the harmful effects of various chemical, biological, and physical agents on living organisms.
Ecotoxicology
The study of the harmful effects of toxicants at the population and ecosystem levels
Terrestrial
Aquatic
Chemodynamics
The study of the release, distribution, degradation, and fate of chemicals in the environment
- Entry paths for chemicals
Evaporation –> Atmosphere
Dissolution –> Hydrosphere
Adsorption –> Lithosphere
Types of environmental pollutants
Air pollutants
Water and soil pollutants
Examples of air pollutants
Indoor and Outdoor
Particles
Gases
Volatile organic compounds
Types of water and soil pollutants
Inorganic ions
Phosphates
Fluoride
Nitrates (Fertilizers, Animal manure)
Synthetic and persistent chemicals:
One word: “plastics”
Sources of environmental pollutants
The main sources of pollution are household activities, factories, agriculture, and transport. Once they have been released into the environment, the concentration of some pollutants is reduced by dispersion, dilution, deposition, or degradation.
–> microplastics
What is eutrophication?
Harmful algal blooms, dead zones, and fish kills are the results of a process called eutrophication — which occurs when the environment becomes enriched with nutrients, increasing the amount of plant and algae growth to estuaries and coastal waters.
Bioavailability
The portion of the total quantity of a chemical present in the environment that is potentially available for uptake by a specific organism
- Behavior and Ecosystem
- Speciation
- Phase partitioning
Bioaccumulation
How pollutants enter the food chain and accumulate in relationship to their absorption
Biomagnification
Increase in contaminant concentration as it moves through a food web
What is occupational toxicology?
Occupational toxicology is the application of the principles and methodology of toxicology toward chemical and biologic hazards encountered at work. The objective of the occupational toxicologist is to prevent adverse health effects in workers that result from their work environment.
What is the primary objective of occupational toxicology?
To assess the permissible dose (concentration/duration/frequency) of exposure to toxicants encountered in the work environment
What are occupational exposure limits?
Conditions under which workers can be repetitively exposed to chemical, biological and physical agents without adverse effects
How are occupational exposure limits determined?
- Experimental animals
- Clinical observations:
- Clinical expressions might be indistinguishable from those arising from non-occupational exposures
- Long interval between the exposure and expression of disease
- Multifactorial nature of diseases linked to occupational exposures - Epidemiological studies
- Prospective studies
- Retrospective studies
What is the difference between a prospective and retrospective epidemiological study?
In prospective studies, individuals are followed over time, and data about them is collected as their characteristics or circumstances change. Birth cohort studies are a good example of prospective studies.
In retrospective studies, individuals are sampled, and information is collected about their past.
Interactors and modifiers of environmental/occupational toxicity
- Environmental and occupational exposures very often if not always
happen as mixtures
Potentiate or enhance toxic effects
Additive
Synergistic
Antagonistic - Other
Lifestyle
alcohol, diet, fitness
Medication and disease state
Genetics (gender) and age
What is the goal outcome of Occupational Toxicology?
- Reduce exposure to toxicants
- Provide screening of health and wellness and exposure monitoring
What is the surveillance of occupational toxicology?
- The ongoing systematic collection, analysis, interpretation, and dissemination of data for the purpose of prevention.
- Detect excessive exposures before the occurrence of disturbances (biological and health)
- Environmental monitoring
- Biological monitoring
Environmental monitoring
a. Tailored to the agent and environment
b. Repeated measures
c. Group based
Biological monitoring (Biomonitoring)
a. The measurement of environmental chemicals and/or their
metabolites in biological media.
b. An important tool for assessing exposure to both naturally
occurring and synthetic chemicals.
c. Measures “molecular signatures” of effect
d. Routes of excretion, blood, bronchial lavage, “dead” tissue
e. Influenced by individual behavior and physiology
What is a toxin?
Poison originated from a biological process (an organism)
Venomous vs Poisonous
Venomous
- Venom produced in exocrine glands or groups of cells
- Delivered during a biting or stinging act
Poisonous
- No mechanisms of delivery
- Poisoning occurs via ingestion or skin absorption
Targets for venoms/poisons in the neuromuscular synapse
Inhibition of ADP-induced platelet aggregation –> bee
Inhibition of epinephrine-induced platelet aggregation –> snake
Prothrombin activation –> snake
Thrombin inhibition –> snake
Other components of venoms
- Amino acids, polypeptides, and proteins
- Lipids and Steroids
- Amines and Neurotransmitters
- Polysaccharides
Proteases
Extracellular matrix –>
Proteases to degrade extracellular matrix
Thrombin-like
Proteolytic enzymes: Snake venom
thrombin-like enzymes (svTLEs)
Inhibitors of Protein and Lipid synthesis; Cytoskeleton
Mycotoxins
- Phalloidin (stabilizes the actin cytoskeleton) and amatoxins (RNA polymerase) from
Symptoms of venom
- Pain
- Allergies
- Cough reflex
Mechanism of pain from venom
Peripheral sensory neuron terminal
Neuropathic pain
can happen if your nervous system is damaged or not working correctly. You can feel pain from various levels of the nervous system—the peripheral nerves, the spinal cord, and the brain. About 30% happens because of diabetes, but other diseases
like alcoholism and shingles can cause it.
Inflammatory pain
Is the spontaneous hypersensitivity to pain that occurs in response to tissue damage and inflammation (e.g., postoperative pain, trauma, arthritis).
