Chapter 1: Introduction to Toxicology

Question 1

Toxicant

Answer 1

A substance capable of producing a toxic effect when in contact with a living organism at a sufficiently high concentration.

Question 2

Contaminant

Answer 2

(this is a synonym of toxicant): A substance that pollutes, spoils or poisons something [in the environment].

Question 3

Toxin

Answer 3

A toxicant produced by a living organism (microbe, plant, or animal).

Question 4

What is the difference between a poisonous a venomous animal?

Answer 4

A poisonous animal must be touched by you (secreting the toxin/poison onto itself), and a venomous animal injects the toxin into you. Therefore a venomous animal is not harmful if touched, only if bitten.

Question 5

Explain what teratogen means and provide an example.

Answer 5

Teratogen is a substance that is capable of causing malformation during the development of the fetus in utero.

ie: thalidomide in the late 50s and early 60s to stop morning sickness caused phocomelia (limbs close to the trunk were severely underdeveloped).

Question 6

Mutagens

Answer 6

Physical or chemical agents that change the genetic material, usually DNA, of an organism and thus increases the frequency of mutations about the natural background level.

Question 7

Carcinogen

Answer 7

Any substance, radionuclide, or radiation that is an agent DIRECTLY involved in causing cancer.

Question 8

Xenobiotics

Answer 8

Substances foreign to life (human made substances; does not exist in nature).

Question 9

What is PCB? What does it do?

Answer 9

polychlorinated biphenyl. can harm developing fetus and infant. can interfere with the body natural hormones. may decrease fertility. may increase cancer risk.

Question 10

What is PBB? Where can you find it?

Answer 10

polybrominated biphenyl. found in consumer appliances that heat up when in use, textiles (lab coats), plastic foams (firefighters).

Question 11

What is PBDE? Where can you find it?

Answer 11

polybrominated diphenyl ethers. can be found in plastics, textiles, electronic castings. recently been banned.

Question 12

What are POP?

Answer 12

persistent organic pollutants. are extremely stable in the environment.

Question 13

What are legacy pollutants?

Answer 13

very persistent in the environment, but their use has been banned. still show up in nature.

Question 14

How does modern medicine help people as compared to primitive medicine?

Answer 14

In primitive medicine, we may have figured out that a certain plant helps lower fever, but we would ingest the WHOLE plant which included the fever lowering compound alongside all the other compounds present in the plant. In modern medicine, we managed to isolate just the fever lowering compound so we don’t ingest extra compounds.

Question 15

What is the Ebers Papyrus?

Answer 15

A compilation of medical texts in 1550 BC (Egyptian). It is one of the earliest written medical (toxicology) documents. It contains the directions for the collection, preparation and administration of over 900 medicinal and poisonous recipes.

Question 16

Who is Paracelsus?

Answer 16

He was a German physician-alchemist who formulated views that remain part of modern toxicology, pharmacology, and therapeutics.

Question 17

What is Paracelsus’ Principles? Provide an example of a chemical that falls under Paracelsus’ principle.

Answer 17

One should make distinctions between the therapeutic and toxic properties of chemical. Basically, at what does is the chemical beneficial (so therapeutic), and at what does is it toxic (so harmful)?

ie: Warfarin is a blood thinner to treat heart conditions at regulated doses, but at high doses it is a rodenticide.

Question 18

Who is Mathieu Orfila?

Answer 18

The father of forensic toxicology. Used autopsy material and chemical analysis to provide legal proofs of poisoning.

Question 19

What did Rachel Carson achieve?

Answer 19

Environmental movement in the 1960s. Wrote “silent spring” on the dangers of pesticides. discussed the link between egg-shell thinning in birds from industrially synthesized pesticides. spurred a national policy on pesticides in the US and alter led to ban on DDT in 1972.

Question 20

What does economic externality mean?

Answer 20

a cost or burden of production that is not paid for by the company, often paid by society.

Question 21

What are EDCs? Provide an example of an EDC.

Answer 21

endocrine disrupting compounds in the 1990s. chemicals that mimic or disrupt hormone function. most commonly mimic estrogen in the body.

ie: Bisphenol A

Question 22

What is mechanistic toxicology?

Answer 22

Focuses on understanding specific physiological, biochemical and molecular mechanisms by which toxicants have their effect.

Question 23

What is descriptive toxicology?

Answer 23

Focuses on the toxicity testing of chemicals.

Question 24

What is clinical toxicology?

Answer 24

Focuses on effects (usually in humans) cased by or uniquely associated with toxicants.

Question 25

What is forensic toxicology?

Answer 25

Focuses on the medical and legal aspects of toxicants on humans and animals.

Question 26

What is reproductive toxicology?

Answer 26

Studies the occurrence of adverse effects of toxicant exposure on the male/female reproductive system.

Question 27

What is developmental toxicology?

Answer 27

Studies life-long adverse effects of toxicants arising from exposures: before conception, during development, postnatal to puberty.

Question 28

What is occupational toxicology?

Answer 28

Focuses on toxicological hazards occurring in workplace with the objective of preventing adverse effects in workers.

Question 29

What is environmental toxicology?

Answer 29

Focuses on detecting compounds and impacts in the natural environment. Largely focuses on the compound.

Question 30

What is ecotoxicology?

Answer 30

Impacts on animals and populations in a natural ecosystem. Largely focuses on the ORGANISMAL response.