Rn Toxicology: Chapter 5

Front 1

disposition of chemicals

Back 1

absorption, distribution, biotransformation, elimination

Front 2

disposition

Back 2

determine concentration at the site of action and dictates the potential for adverse events to occur

Front 3

main sits of absorption

Back 3

GI tract, lungs, and skin

Front 4

absorption

Back 4

the transfer of a chemical from the site of exposure into the systemic circulation; enters bloodstream

Front 5

rate of absorption depends on

Back 5

concentration, area exposed, characteristics of the layer, blood circulation, phisiochemical properties

Front 6

amphiphillic molecules

Back 6

contains both hydrophobic and hydrophobic moieties

Front 7

saturated fatty acids

Back 7

maximizes London dispersion interactions; melting point increase b/c of straight chain

Front 8

unsaturated fatty acids

Back 8

predominantly cis configuration, melting point is lower b/c of bent chain

Front 9

integral/intrinsic proteins

Back 9

associate tightly with the membrane through the hydrophobic interactions

Front 10

lipid-linked protiens

Back 10

anchored to membrane through covalently attached lipids

Front 11

peripheral/extrinsic proteins

Back 11

loosely connected to membranes and can be dissociated by mile procedures

Front 12

passive process

Back 12

high concentration to low concentration

Front 13

translocate

Back 13

low concentration to high concentration

Front 14

paracellular diffusion

Back 14

small hydrophillic molecules travel through aqueous pores

Front 15

transcellular diffusion

Back 15

hydrophobic molecules diffuse across the lipid domain

Front 16

negative logP

Back 16

water soluble

Front 17

positive logP

Back 17

lipid soluble

Front 18

facilitated diffusion

Back 18

transportation where substrate is not moved against a concentration gradient, and the transport process does not require input energy

Front 19

active transport

Back 19

movement against concentration gradient; saturability at high concentration selectivity of certain structures; requires energy

Front 20

ATP binding cassette transporters (ABC)

Back 20

binding and hydrolysis of ATP provides the energy required to move their substrates across memebranes

Front 21

lipid soluble compounds move by

Back 21

diffusion

Front 22

water soluble chemicals move by

Back 22

diffuse transcellular pores and/or across the cell membrane

Front 23

highly ionized/hydrophillic xenobiotics move by

Back 23

specialized membrane carrier systems

Front 24

absorption increases with ______ particle diameter

Back 24

decreasing

Front 25

pH of stomach

Back 25

2

Front 26

pH of small intestine

Back 26

6.6

Front 27

weak organic acids are absorbed more through the stomach or small intestine

Back 27

stomach

Front 28

organic bases are absorbed more through the stomach or small intestine

Back 28

small intestine

Front 29

factors influencing absorption through the skin

Back 29

strength of outer-most skin; hydration of the outer-most skin; temperature; solvents size and physical properties

Front 30

caustic agents _____ skin permeability

Back 30

increase

Front 31

increase in temp will ____ dermal penetration by ____ blood flow

Back 31

increase; increase

Front 32

intravenous route

Back 32

introduces toxicant directly to bloodstream

Front 33

factors affecting distribution

Back 33

binding to plasma proteins; special barriers; distribution to storage sites that are not target sites; export from cells

Front 34

two organs that accumulate chemicals

Back 34

liver and kidneys

Front 35

detoxication

Back 35

biotransformation that eliminates ultimate toxicant or prevents its formation (liver and kidney)

Front 36

excretion

Back 36

physical mechanism of the removal of xenobiotics from the blood and their return to the external environment (urine; feces; lungs)