Tox 300 FINAL QUESTIONS WITH CORRECT ANSWERS.

Tox 300 FINAL QUESTIONS WITH CORRECT
ANSWERS

oral |bioavailability |- |CORRECT |ANSWER✔✔-the |fraction |of |an |orally |administered |xenobiotic |
that |reaches |the |systemic |circulation |in |an |unchanged |form



Toxicokinetics |- |CORRECT |ANSWER✔✔-determination |of |the |time |course |of |disposition |
(ADME) |of |xenobiotics |in |the |body. |

Determines |the |concentration |of |xenobiotic |at |its |site |of |action |thus, |is |linked |to |the |intensity |
of |biological |effect.



Who |said |"The |dose |defines |the |poison" |? |- |CORRECT |ANSWER✔✔-Paracelsus |- |Phillipus |
Aureolus |Theophrastus |Bombastus |von |Hohenheim |(1493-1541)



Most |abundant |plasma |protein |in |the |blood |- |CORRECT |ANSWER✔✔-Albumin



Routes |of |absorption |- |CORRECT |ANSWER✔✔-Ingestion |- |GI |tract, |small |intestine

dermal/skin |- |lipid |soluble |solvents

inhalation |- |lungs |absorption |of |gases |and |vapors

IV/SubC/IM/IP |- |clinical/experiment |(pharmacology)



the |most |important |feature |of |a |chemical |- |CORRECT |ANSWER✔✔-Lipophilicity |

- |ability |to |readily |cross |membranes



Absorption |pathways |- |CORRECT |ANSWER✔✔-1. |passive |diffusion

,2. |filtration |(bulk |flow)

3. |active |transport

4. |facilitated |diffusion

5. |phagocytosis |and |pinocytosis



types |of |passive |diffusion |- |CORRECT |ANSWER✔✔-a. |very |small |hydrophilic |molecules

b. |lipophilic |organic |chemicals

c. |weak |organic |acids/bases



Absorption |via |passive |diffusion |- |CORRECT |ANSWER✔✔-follows |with |the |concentration |
gradient



diffusion |of |very |small |hydrophilic |molecules |occurs |by |- |CORRECT |
ANSWER✔✔-paracellular/PASSIVE |diffusion |

- |follows |concentration |gradient |(passive)

- |i.e. |ethanol



chemical |that |is |absorbed |via |paracellular |diffusion |- |CORRECT |ANSWER✔✔-ethanol



diffusion |of |lipophilic |organic |chemicals |occurs |by |- |CORRECT |ANSWER✔✔-transcellular |
diffusion

- |attracted |to |lipids

- |Kow |coefficient |

- |follows |concentration |gradient |(passive)



diffusion |of |weak |organic |acids/bases |occurs |by |- |CORRECT |ANSWER✔✔-passive |diffusion

- |follows |concentration |gradient

,- |75% |of |PPCP's

- |POP's |log |Kow |>5



Henderson-hassleback |equation |- |CORRECT |ANSWER✔✔-= |log |Protonated/non-protonated |= |
pKa |- |pH

log |= |pKa |-pH



absorption |via |filtration |(bulk |flow) |- |CORRECT |ANSWER✔✔-follows |pressure |gradient

- |transports |with |water |through |cell |junctions |(gaps)

- |important |in |the |kidney



absorption |via |active |transport |- |CORRECT |ANSWER✔✔-*requires |energy |ATP

- |AGAINST |concentration |gradient

- |pump |for |elimination |of |xenobiotics |

- |i.e. |MDR |proteins |which |are |important |in |excretion



absorption |via |facilitated |diffusion |- |CORRECT |ANSWER✔✔-important |in |excretion |of |
xenobiotics

OAT's |- |organic |anion |transporter



absorption |via |phagocytosis |and |pinocytosis |- |CORRECT |ANSWER✔✔-most |important |in |the |
lungs |

very |fine |particulate |matter



what |are |cell |junctions |called |in |the |kidney |- |CORRECT |ANSWER✔✔-glomeruli



cell |junction |size |in |the |kidney |vs |CNS |- |CORRECT |ANSWER✔✔-glomeruli |= |70 |nm

, CNS |= |0 |nm

most |cell |size |= |4 |nm



why |are |there |no |cell |junctions |in |the |CNS |- |CORRECT |ANSWER✔✔-protective |mechanism |of |
the |blood |brain |barrier |(BBB) |so |that |no |filtration |occurs



how |does |the |phrase |"like |is |not |ionized |in |like" |influence |weak |acids/bases |and |pH |- |CORRECT
|ANSWER✔✔-a |weak |acid |is |non-ionized |in |more |acidic |medium



a |base |is |more |non-ionized |in |a |basic |medium

increase |in |pH |= |more |in |the |non-protonated |form



ion-trapping |- |CORRECT |ANSWER✔✔-i.e. |mastitis

breast |milk |is |an |acidic |medium, |using |a |weak |base |antibiotic |causes |it |to |go |into |the |more |
protonated |form |and |is |therefore |trapped |in |the |breast |milk



advantages |of |IV |drug |administration |- |CORRECT |ANSWER✔✔-complete |absorption

accurate |titration |dose

can |give |large |volumes

can |give |tissue |irritants



disadvantages |of |Oral |drug |administration |- |CORRECT |ANSWER✔✔-variable |absorption

relies |on |owner/patient |compliance



Factors |affecting |absorption |- |CORRECT |ANSWER✔✔-- |stability |of |the |drug |in |gastric |acids |and
|digesting |enzymes



- |food |in |stomach

- |hepatic |first-pass |metabolism