Toxicology 1

Question 1

Define

Toxicology

Answer 1

Study of adverse effects of chemicals in biological systems

Question 2

Who said

All things are poison and nothing is without poison, only the dose makes a thing not a poison

Answer 2

Paracelsus

Question 3

Define

ecotoxicology

Answer 3

study of effects of pollution on entire ecosystem

Question 4

Differentiate

Toxicology vs ecotoxicology

Answer 4

Toxicology: chemicals → bio system
Eco: pollution → entire ecosystem

Question 5

Relative Toxicity

Answer 5

Relative to dose & relative to person taking dose

Question 6

Dose-Response Relationship

Answer 6

Quantitative description of the association between exposure & toxic effects produced

Question 7

Requirements for Dose-Response Relationship to have a toxic effect

3

Answer 7

1. Chemical or active metabolite that causes an adverse reaction in the body
2. Must have sufficient concentration to have an effect
3. Must persist long enough to exert the effect

Question 8

Considerations for a Dose-Response Relationship

3

Answer 8

1. Must be known that response is due to compound exposure
2. Response Magnitude should be a function of dose administered
3. Should have a quantitative method for measuring response

Question 9

LD50

Also: what are the units?

Answer 9

Lethal Dose 50

• Dose of chemical that kills 50% of exposed population in a defined time frame
• Dose per kg of bodyweight (mg/kg)

Question 10

How do we determine LD50?

Answer 10

Rats (aka through toxicology! lol)

Question 11

Major Routes of Exposure

Answer 11

Contact
Ingestion
Inhalation

Question 12

Describe

Contact Exposure
What happens?
What does skin absorb & not absorb?

Answer 12

Absorption over time
skin is Hydrophobic & lypophilic

Question 13

Describe

Ingestion Exposure

Answer 13

• Guts absorb maximum amt of substances it can digest (Bc Body assumes you are responsible)
• “Free for all” down there

Question 14

Describe

Inhalation Exposure

Answer 14

Inside chest cavity – protection

Question 15

Toxicant Classifications

3

Answer 15

1. Chemical Class
2. Source of Exposure
3. Organ system affected

Question 16

How do we classify chemical class?

Answer 16

accdg to functional group

Question 17

Chemical class examples add for long exam

Question 17

Source of exposure
To air: ____
To water: ___

Answer 17

To air: ‘emission’
To water: ‘discharge’

Question 18

List

Organ Systems affected

5

Answer 18

1. Liver
2. Kidneys
3. Spine
4. DNA
5. Fetus

Question 19

Main organs usually affected

2

Answer 19

Liver, kidneys

Question 20

What does the liver do?

Answer 20

Liver breaks down things (alcohol, proteins), Detoxifier

Question 21

What do kidneys do?

Answer 21

filter waste from blood,
Can pee it out

Question 22

How is our DNA affected by toxicant?

Answer 22

Once DNA is damaged, DNA replication is at risk

Question 23

How does the fetus become affected by toxicant?

Answer 23

• Umbilical cord & Amniotic fluid
• Creates its own blood supply

Question 24

Why do toxicologists favor studying the organ system affected?

Answer 24

it’s easier for them to think about & target

Question 25

# Define Xenobiotic

Answer 25

chemical foreign to the body

Question 26

Sequence of response | 4

Answer 26

Absorption Distribution Metabolism Excretion

Question 27

# Define Toxicokinetics

Answer 27

processes in the toxicological sequence

Question 28

What is the importance of studying toxicokinetics?

Answer 28

Knowing process of response **helps you develop treatment** against substance Or prevent it from spreading further

Question 29

# Describe Absorption

Answer 29

Traversing biological barrier (Aka blood)

Question 30

Common pathways of absorption | 3

Answer 30

Gastrointestinal system Pulmonary alveoli Skin

Question 31

# Describe Absorption through Gastrointestinal system

Answer 31

* Design: **nutrient absorption** * **Large surface area** with numerous **transport systems** * Most taken advantage of by pathogens (they will try to enter system) * Be careful of what you ingest!

Question 32

# Describe Absorption through Pulmonary alveoli

Answer 32

Gas exchange between air & blood

Question 33

What gets absorbed through Pulmonary alveoli?

Answer 33

**Small particles & aerosols** * Diffusion of most water-soluble compounds * Lipid-soluble compounds also absorbed

Question 34

How does Diffusion of most water-soluble compounds happen in the Pulmonary Alveoli?

Answer 34

Mucous lining *more explanation pls*

Question 35

# Absorption through Skin What kinds of compounds can penatrate & not penetrate skin?

Answer 35

* Effective barrier for water-soluble * Lipid-soluble compounds readily penetrate skin & enter blood stream

Question 36

2 ways Distribution takes place

Answer 36

Bloodstream Intestines/Liver

Question 37

What law does Distribution follow?

Answer 37

laws of diffusion

Question 38

In distribution through the intestines & liver, [many/few] chemicals are excreted in an unchanged form

Answer 38

few

Question 39

How are water soluble chemicals excreted?

Answer 39

urine

Question 40

How are fat soluble chemicals excreted?

Answer 40

Converts to bile first, excreted through feces

Question 41

What happens when the body doesn’t know how to get rid of a substance?

Answer 41

Stores it (ex. lead deposit in bones)

Question 42

# Define Biotransformation

Answer 42

enzyme-mediated metabolic conversion

Question 43

Where does metabolism take place and why?

Answer 43

Mostly in **liver**, bc rich in metabolic enzymes Nearly all cells have some capacity for metabolism Recall: detoxifying organ

Question 44

What products are usually formed from metabolic transformations (metabolism)?

Answer 44

Products are most polar and less fat soluble (for excretion via urine)

Question 45

What does the field of carcinogenesis tackle?

Answer 45

When metabolism yields more toxic products than original

Question 46

# T/F Metabolites cannot combine with cellular nucleophiles

Answer 46

F They can combine w/ DNA & RNA

Question 47

What do you call substances that affect the DNA?

Answer 47

mutagen