Exam 2 Flashcards
Quantitative risk assessment…
ascertains the quality of the available experimental data
What is the highest prioritized US EPA default for data selection in hazard identification and dose response?
Select human data over animal data
True or False. Asthma is characterized by open airways and easy gas exchange
False
In the conducting airway, what are the anatomic structures that induce protective effects?
Mucus
Cilia
Mucous layer
What is cancer characterized by?
- Uncontrolled cell growth and cell metastasis
- Mutations and aberrant gene expression
Steps of Multistage Carcinogenesis
Initiation -> promotion-> progression
DNA damage -> proliferation -> proliferation
What is the multi-stepped process of cells in cancer?
Normal -> hyperplasia -> mild dysplasia -> carcinoma in situ -> cancer (invasive)
What are the two types of genotoxic carcinogens?
Direct-acting
Indirect-acting
What are some characteristics of direct-acting carcinogens?
- don’t require metabolic activity
- highly electrophilic
- interact with macromolecules
- ultimate carcinogens
- test positive in Ames Test
- cause tumors at site of exposure
- detoxification pathways can inactivate
What are some characteristics of indirect-acting carcinogens?
- require metabolic activity
- metabolites are highly electrophilic
- interact with macromolecules
- ultimate carcinogen
- cause tumors at target tissue site
- detoxification pathways can inactivate
What are the difference DNA repair pathways?
- direct reversal of DNA damage
- excision repair, base excision repair, nucleotide repair, or mismatch repair
- postreplicational repair (recombination repair)
- nonhomologous end-jointing, double strand break repair
What acts as the accelerator in cells?
proto-oncogenes
What acts as the brake in cells?
tumor suppressors
What do 90% of all human cancers have dysregulating?
p53
What is the BBB extremely sensitive to?
oxygen and glucose
What are the energy requirements of the BBB?
highly dependent on aerobic metabolism
What are the differences between systemic capillaries and brain capillaries?
Systemic- fenestration and abundant pinocytosis
Brain- tight junction and lack pinocytosis
What are the three components of axonal transport?
Fast axonal transport
Intermediate axonal transport
Slow component
What is axonopathy?
axon degenerates while neuronal cell body continues to survive
What is Wallerian degeneration?
degeneration of distal nerve stump
How is myelin formed?
CNS- oligodendrocytes
PNS- Schwann cells
What are the four targets of neurotoxicity?
neuron, axon, myelinating cell, neurotransmitter system
Can axons regenerate?
CNS- no
PNS- yes
Can myelin regenerate?
CNS- very limited
PNS- Schwann cells capable of remyelinating the axon
What enhances dopaminergic neurotransmission?
cocaine
What do nasal passages function as?
filters for larger particles
Where does gas exchange take place?
alveoli
What do type 1 and 2 alveolar cells do?
1- cover large SA
2- produce surfactant, mitotic division into type 1
What cells contain a high content of xenobiotic-metabolizing enzymes?
clara cells
What is bronchoconstriction triggered by?
irritants, drugs, peptides
What is fibrosis?
increased amounts of collagen that causes lung stiffness
What are some blood-borne agents that cause pulmonary toxicity in humans?
paraquat monocrotaline bleomycin cyclophosphamide cationic amphophilic drugs
What are methods for studying injury of respiratory systems?
- Inhalation exposure systems
- Pulmonary function studies
- morphologic techniques
- pulmonary lavage
- in vitro approaches
What are biomarkers?
biological indicators of exposure or effects detected in body fluids and other tissues
-provide info relative to internal exposure and disease
What are the types of biomarkers?
- parent agent
- biotransformed parent agent (metabolite)
- increased/decreased endogenous levels of biochemicals
- altered biochemical/cellular component/ cell
What is the allergy mechanism?
Hapten + tissue protein = complete antigen –> sensitized t-lymphocytes
What are examples of biomarkers of response?
- decreased cells
- elevated liver enzymes
- increased release of biochemical
What are some factors that influence intensity of response?
- duration and rate of entry
- concentration and dose
- mode and route of exposure
- acute vs. chronic
- age and state of health
- dose-response
- env. variables
- genetics
