Toxicokinetics -AD

Question 1

how a substance gets in the body and what happen to it in the body

Answer 1

Toxicokinetics

Question 2

Four processes involved in toxicokinetics

Answer 2

1. Administration
2. Distribution
3. Biotransformation
4. Excretion

Question 3

The substance enters the body

Answer 3

Absorption

Question 4

Substance move from the site of entry to other areas of the body

Answer 4

Distribution

Question 5

The body changes the substances into new chemicals

Answer 5

Biotransformations

Question 6

The substance or its metabolite leave the body

Answer 6

Excretions

Question 7

Studying the kinetics of all substances

Answer 7

Toxicokinetics

Question 8

Use to describe the time course of movement of chemicals through the body

Answer 8

Disposition

Question 9

Factors that determine the severity of toxicity that results when a xenobiotic enters the body

Answer 9

Toxicants disposition and its biological activity

Question 10

Toxicants gain entry to the body

Answer 10

Absorption

Question 11

Most important several factors affect the xenobiotic to be absorbed

Answer 11

1. Route of exposure
2. Concentration of substance at the site of contact
3. chemical and physical properties of the substance

Question 12

Primary routes of exposure by which xenobiotic can gain entry into the body are

Answer 12

1. GI tract
2. Respiratory tract
3. Skin

Question 13

The main route for many pharmaceuticals

Answer 13

GI tract

Question 14

Some pharmaceuticals that is absorbed in respiratory tract

Answer 14

Aerosols and inhalers

Question 15

Other routes of exposure

Answer 15

1. Implants
2. Injection
3. Conjunctival instillations
4. Suppositories

Question 16

This permit slow and time release. (Ex)
For minimal absorptions (Ex)

Answer 16

Implants

Hormones
Artificial lenses or tendons

Question 17

Primarily used for pharmaceuticals

Answer 17

Injection

Question 18

Primarily treatment of ocular conditions

Answer 18

Conjunctival instillations

Question 19

For drugs intended for local effect, usually __

Answer 19

Suppositories; vagina and rectal

Question 20

Are formidable barriers, and an effective body defense that prevents foreign invaders or substances from entering the body

Answer 20

Cell membranes

Question 21

Surrounds all body cells and are similar in structure

Answer 21

Cell membrane

Question 22

Head is

Answer 22

Polar; hydrophilic; outward

Question 23

Tail

Answer 23

Nonpoalr; lipophilic; inward

Question 24

Those that can cross the cell membrane 2 methods

Answer 24

Passive transfer or facilitated transport

Question 25

Consist of simple diffuse across the cell membrane; no cellular energy is required

Answer 25

Passive transfer

Question 26

Require assistance or are facilitated by specialized transport mechanism

Answer 26

Facilitated transport

Question 27

Example of specialized transport mechanism

Answer 27

1. Facilitated diffusion 2. active transport 3. endocytosis

Question 28

Most common way that xenobiotics cross the cell membrane

Answer 28

Passive diffusion

Question 29

Two factors that determine the rate of passive diffusion of cell membrane

Answer 29

1. concentration of the substance on both sides 2. ability of the substance to move

Question 30

Properties of the chemical substance that affects its ability for passive transfer

Answer 30

Lipid solubility Molecular size Degree of ionization

Question 31

Most aqueous pore are about __ in size and allow chemicals of molecular weight of __ to pass through

Answer 31

4A in size; 100-200

Question 32

similar to diffusion in a way that it does not energy and follows a concentration gradient

Answer 32

Facilitated diffusion

Question 33

Carrier mediated transport; faster and capable of moving larger molecules

Answer 33

Facilitated diffusion

Question 34

Examples of facilitated diffusion

Answer 34

Transport of sugar and amino acid

Question 35

Movement through the membrane may be against the concentration gradient, from lower conc to higher conc

Answer 35

Active transport

Question 36

Active transport require this energy

Answer 36

cellular energy from ADP

Question 37

A toxicant can leave the interstitial fluid by:

Answer 37

1. entering local tissue 2. entering blood capillaries or blood circulatory system 3. entering lymphatic cells

Question 38

Active transport is essential in transporting xenobiotics into the ___.

Answer 38

Liver, kidney, CNS

Question 39

When the substance cannot enter cells via passive or active mechanism, they may still enter through a process known as

Answer 39

Phagocytosis and pinocytosis

Question 40

In this process the cell surrounds the substance with a section of its cell wall

Answer 40

Endocytosis

Question 41

The two primary forms of endocytosis

Answer 41

Phagocytosis, Pinocytosis

Question 42

Large particles suspended in the extracellular fluid are engulfed and transported into cells or destroyed

Answer 42

Phagocytosis

Question 43

Engulfing liquids or tiny particles in suspension within extracellular fluid

Answer 43

Pinocytosis

Question 44

Primary distribution of absorbed chemical is by __?

Answer 44

Blood

Question 45

The total volume of body fluids in which a toxicant is distributed is the __.

Answer 45

apparent volume of distribution (Vd)

Question 46

The VD is expressed in __

Answer 46

Liters

Question 47

Formula for calculation of volume of distribution

Answer 47

VD = dose (mg)/ plasma conc (mg/L)

Question 48

Provide reasonable estimates of how extensively the toxicant is distributed in the body

Answer 48

Volume of distribution

Question 49

The body burden for a toxicant can be estimated from knowledge of Vd by using the formula __.?

Answer 49

body burden (mg) = plasma conc (mg/L) x VD (L)

Question 50

Once a chemical is in the bloodstream, it may be __.?

Answer 50

ESBIT Excreted Stored Biotransformed into different chemicals Its metabolite may be excreted or stored The chemical or metabolites may interact or bind with cellular component