NUFS150 - Basic Principles in Toxicology II

Question 1

What are the 3 phases of drug/toxicant action?

Answer 1

Exposure, Toxokinetic, and Toxodynamic are the 3 phases of drug/toxicant action.

Question 2

Describe: exposure phase of drug action.

Answer 2

Toxicant is vulnerable to environmental factors such as chemical transformation, degradation, biodegredation, and disintegration.

Question 3

Describe: toxokinetic phase of drug action.

Answer 3

Toxicant is absorbed (through cell membrane), distributed (among tissues and organs), metabolized, and excreted by an organism.

Question 4

Describe: toxodynamic of drug action.

Answer 4

Toxicant reacts to specific sites on/inside the cell; Toxicant produces toxic effect.

Question 5

What is the crucial step for a xenobiotic to undergo the toxokinetic phase?

Answer 5

Absorption is needed for a xenobiotic to undergo the toxokinetic phase.

Question 6

What are the 3 factors that affect xenobiotic absorption?

Answer 6

Route of exposure. Concentration of substance at contact. Chemical/physical properties of substance.

Question 7

What are the 3 primary routes of xenobiotic exposure?

Answer 7

Gastrointestinal tract, respiratory tract, and skin are 3 major routes xenobiotics are absorbed.

Question 8

What are the 3 primary types of specialized transport methods?

Answer 8

Facillitated diffusion, Active transport, and Endocytosis (phagocytosis, pinocytosis).

Question 9

What are 2 factors that affect the toxicity of a compound?

Answer 9

2 factors that affect the toxicity of a compound are exogenous factors and endogenous factors.

Question 10

Give a few examples of exogenous factors affecting toxicity.

Answer 10

Structure of compound, dose, frequency of exposure, route of exposure, and presence of other compounds.

Question 11

Give a few examples of endogenous factors affecting toxicity.

Answer 11

PHYSIOLOGY and morphology of the GI TRACT, nature of INTESTINAL BACTERIA, METABOLIC ACTIVITY of the body.

Question 12

Define: dose.

Answer 12

Dose is a quantity of a drug/medicine consumed.

Question 13

What are the 2 types of biological effects occur with increasing dose?

Answer 13

Type I: No effect, toxic effect, fatal effect. Type II: no effect, beneficial effect, toxic effect, fatal effect (ex. Nutrition, therapeutic, nutrition+therapeutic).

Question 14

What are the 4 types of doses?

Answer 14

Exposure, Absorbed, Administered, and Total dose.

Question 15

Define: exposure dose.

Answer 15

Exposure dose is the amount of a xenobiotic encountered in the environment.

Question 16

Define: absorbed dose.

Answer 16

Absorbed dose is the actual amount of exposed dose that enters the body.

Question 17

Define: administered dose.

Answer 17

Administered dose is the quantity consumed/injected.

Question 18

Define: total dose.

Answer 18

The sum of exposure, absorbed, and administered doses.

Question 19

Describe the dose-response relationship concept.

Answer 19

Establishes: causality (observed effect), least amount of the dose (threshold effect), and rate at which harmfulness increases (response).

Question 20

What factors effect dose-response.

Answer 20

Depends on the subject, group of subjects, half the population, and all of the population.

Question 21

What is a lethal dose?

Answer 21

A lethal dose is the amount of a substance that will produce 50% mortality when administered.

Question 22

How do long chain fatty acids interact with toxicants?

Answer 22

Long chain fatty acids react with metals, and create metallic soaps.

Question 23

How do phosphates interact with toxicants?

Answer 23

Phosphates form insoluble salts with toxicants.

Question 24

How does sugar interact with toxicants?

Answer 24

Sugars react with amines/amino acids, which lead to less absorption.

Question 25

How does ascorbic acid interact with toxicants?

Answer 25

Ascorbic acid may inhibit nitrosation reaction in GI tract.