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Toxicology Flashcards
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Toxicology Flashcards
Toxicology Flashcards
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Question
What defines a toxicant and how is toxicity generally characterized?
Answer
A toxicant is any chemical substance dangerous to organisms. Toxicity is dose-dependent, meaning the effect depends on the amount exposed to or ingested.
Question
What distinguishes toxins from toxicants?
Answer
Toxins are toxicants that are produced by organisms, either plants, animals, or microbes, whereas toxicants can also be synthetic or chemical substances.
Question
What is the effect of tropane alkaloid toxins like atropine and scopolamine on the human body?
Answer
They act as anticholinergic agents by blocking acetylcholine at muscarinic receptors in the parasympathetic nervous system, causing effects like pupil dilation, reduced secretions, increased heart rate, and anticholinergic syndrome symptoms.
Question
How is scopolamine used medically, and what effects does it block to help with motion sickness?
Answer
Scopolamine blocks signals from the vestibular system (inner ear) to the brain, preventing dizziness and nausea. It is used in forms like oral tablets and transdermal patches to treat motion sickness and postoperative nausea.
Question
What are cardiac glycosides derived from plants like foxglove, and how do they affect the heart?
Answer
Cardiac glycosides inhibit the sodium-potassium ATPase pump in heart cells, leading to increased intracellular calcium, stronger heart contractions, but also risk dangerous changes in heart rhythm.
Question
What is the primary toxic component of the castor bean, and why is it so deadly?
Answer
Ricin, a ribosome-inactivating protein (RIP), is the primary toxin. It inhibits protein synthesis by preventing ribosomes from functioning, causing cell death and multi-organ failure. Even small doses can be fatal.
Question
Describe the mechanism of urushiol toxicity from poison ivy.
Answer
Urushiol is an oil-based allergenic compound that oxidizes upon air exposure, triggering severe allergic skin reactions (contact dermatitis). It causes itching, redness, swelling, and blistering. It remains active on surfaces for years.
Question
What is abrin, and how does its toxicity compare to ricin?
Answer
Abrin is a highly toxic ribosome-inactivating protein found in jequirity bean seeds, structurally similar but more potent than ricin. It inhibits protein synthesis leading to cell death. Very small quantities can be fatal.
Question
Explain how toxins like atropine cause anticholinergic syndrome and list key symptoms.
Answer
Atropine blocks acetylcholine binding at muscarinic receptors, disrupting parasympathetic functions. Symptoms include dry mouth, blurred vision, dilated pupils, increased heart rate, difficulty urinating, hallucinations, and in severe cases, coma or death.
Question
What are conotoxins produced by cone snails and their general effects?
Answer
Conotoxins are neurotoxins that disrupt ion channels and neurotransmitter functions, causing paralysis, muscle spasms, and respiratory distress. Different types affect sodium, potassium, calcium channels, and neurotransmitter release.
Question
How does tetrodotoxin (TTX) from the blue-ringed octopus affect nerve function?
Answer
TTX blocks voltage-gated sodium channels on nerves, preventing nerve impulses and causing paralysis, including respiratory failure, leading to death if untreated.
Question
What factors influence the spread of toxic spills in the environment?
Answer
State of toxin (solid, liquid, gas), solubility, density, volatility, reactivity, water flow speed, soil permeability, weather conditions (wind, temperature, humidity), terrain slope, and the presence of barriers all affect how toxins spread.
Question
What are common physical and chemical methods used to separate toxic mixtures in environmental cleanup?
Answer
Methods include filtration, sieving, magnetism, precipitation reactions, centrifugation, sedimentation, decantation, distillation (simple and fractional), chromatography, and oxidation-reduction reactions.
Question
How does emulsification affect the difficulty of cleaning up toxic spills?
Answer
Emulsification forms stable droplets or suspensions with water, making the toxic substance remain dispersed instead of separating or settling, complicating removal efforts.
Question
Describe the primary environmental and health impacts of the Bhopal Gas Tragedy.
Answer
Over 500,000 were exposed to methyl isocyanate gas, leading to around 15,000 deaths, long-term birth defects, blindness, respiratory damage, and organ failure due to inhalation of airborne toxic gas.