Toxicology Final
The procedures used to extrapolate from high to low doses primarily depend upon the: Threshold dose of the substance Rate of lethality in laboratory animals Carcinogenicity of the substance
Carcinogenicity of the substance Carcinogenic effects are not considered to have a threshold dose and mathematical models are used to estimate the risk of carcinogenicity at very low doses. Noncarcinogenic effects are considered to have threshold doses and the margin of safety (MOS) is calculated.
The organ system that transports oxygen and nutrients to tissues and removes waste products is the: Urinary system Integumentary system Cardiovascular system
Cardiovascular system The cardiovascular system functions to transport oxygen and nutrients to tissues and removes waste products. The primary organs are the heart, blood, and blood vessels.
The two fundamental anatomical divisions of the nervous system are the: Cerebrum and cerebellum Central nervous system and peripheral nervous system Brain and spinal cord
Central nervous system and peripheral nervous system
In the risk assessment process, what happens during the hazard identification step? Characterization of the relation between doses and incidences of adverse effects Characterization of innate adverse toxic effects of agents Measurement or estimation of intensity, frequency, and duration of human exposures to agents Estimation of the incidence of health effects under the various conditions of human exposure
Characterization of innate adverse toxic effects of agents
The type of epidemiology study in which individuals are identified according to exposure and followed to determine subsequent disease risk is known as:
Cohort study
Modern approaches to hazard identification are based in part on: Extensive animal testing for toxicity Computer models like (Q)SAR Risk assessment strategies
Computer models like (Q)SAR Part of the basis for emerging approaches to hazard identification, such as assessing for potential mutations and DNA damage, relies on (Quantitative) Structure Activity (Q)SAR methods
In the European Union, what regulatory authority is responsible for chemicals and biocides? European Centre for Disease Prevention and Control (ECDC) European Food Safety Authority (EFSA) European Chemicals Agency (ECHA)
European Food Safety Authority (EFSA) The European Food Safety Authority (EFSA) has regulatory authority for chemicals and biocides in the EU.
Adverse Outcome Pathways (AOPs) are methods of hazard identification that: Evaluate changes in normal cellular signaling pathways using human-relevant cells or tissues Identify adverse outcomes in test subjects administered increasing doses of potential toxicants Measure the intensity, frequency, and duration of human exposures to agents Evaluate the health effects under various conditions of human exposure
Evaluate changes in normal cellular signaling pathways using human-relevant cells or tissues Adverse Outcome Pathways (AOPs) are in vitro methods that evaluate changes in normal cellular signaling pathways using human-relevant cells or tissues.
Intuitive toxicology studies show that: All toxicologists think the same Members of the public usually think like toxicologists There can be meaningful differences among toxicologists in how they look at the same set of toxicology study results Intuitive toxicology is not important to consider in communication efforts
There can be meaningful differences among toxicologists in how they look at the same set of toxicology study results
The propagation of an electrical impulse (action potential) down an axon consists of: The transmission of the action potential by chemical neurotransmitters The movement of sodium ions from the dendrite to the axon A continuous series of opening and closing of sodium-potassium channels and pumps
A continuous series of opening and closing of sodium-potassium channels and pumps The propagation of an electrical impulse (action potential) down an axon consists of a continuous series of opening and closing of sodium-potassium channels and pumps. The action potential moves like a wave from one end (dendritic end) to the terminal end of the axon.
Phase 2
A molecule is added to the intermediate metabolite to permit elimination from the body
While animal testing was historically the primary method used in testing for toxicity, modern testing methods prefer: In silico In vitro Refined animal testing All of the above
All of the above
Which of the following are important environmental health issues? Radon in air Lead contamination in drinking water Foodborne illness from contaminated food All of these are important for human health
All of these are important for human health
The FDA develops exposure standards for both direct and indirect food additives. Which of the following is an example of an indirect food additive? A preservative added to food products An antibiotic administered to cattle Natural and artificial flavorings A nutritional supplement, such as Vitamin A
An antibiotic administered to cattle Indirect food additives are not intentionally added to foods and are not natural constituents of foods. Examples include antibiotics administered to cattle, pesticide residues remaining after production or processing of foods, and chemicals that migrate from packaging into foods.
The primary cause of death to neurons and glial cells is: Interference with chemical transmission Interference with electrical transmission Anoxia
Anoxia The most common cause of death of neurons and glial cells is anoxia, an inadequate oxygen supply to the cells or their inability to utilize oxygen.
The process of self-destruction of the cell nucleus (often referred to as "programmed cell death") is known as: Necrosis Apoptosis Cellular swelling Fatty change
Apoptosis
A major mechanism that prevents the action potential (impulse) from moving down an axon is: Blockage or interference with movement of sodium and potassium ions in and out of neuron membrane, changing the action potential Excessive release of chemical neurotransmitters Blocking receptors at the post-synaptic membrane
Blockage or interference with movement of sodium and potassium ions in and out of neuron membrane, changing the action potential Interruption of the propagation of the electrical potential is caused by agents that can block or interfere with the sodium and potassium channels and sodium-potassium pump. This will weaken, slow, or completely interrupt the movement of the electrical potential.
Which issues in environmental toxicology relate to the human food supply? Bioaccumulation of substances in fish Effects of neonicotinic pesticides on bees Both the bioaccumulation of substances in fish and effects of neonicotinic pesticides on bees
Both the bioaccumulation of substances in fish and effects of neonicotinic pesticides on bees
The nucleic acid located in the nucleus, which makes up the chromosomes of cells, is: ATP RNA DNA
DNA
The Acceptable Daily Intake (ADI) is calculated by: Dividing the NOAEL by safety factors Dividing the NOAEL by the LOAEL Multiplying the RfD by a modifying factor Linear extrapolation from the LOAEL to the zero intercept
Dividing the NOAEL by safety factors The ADI is calculated by dividing the NOAEL by safety factors.
A condition of abnormal cell changes or deranged cell growth in which the cells are structurally changed in size, shape, and appearance from the original cell type is known as: Dysplasia Anaplasia Neoplasia
Dysplasia
The organ system that regulates body functions by chemicals (hormones) is known as the: Nervous system Reproductive system Endocrine system
Endocrine system The endocrine system functions to regulate body functions by chemicals (hormones). It contains several organs including the pituitary gland, parathyroid gland, thyroid gland, adrenal gland, thymus, pancreas, and gonads.
What are the phases of the risk-based decision-making framework proposed by the co-authors of the "Silver Book?" Enhanced problem formulation and scoping; planning and assessment; and risk management Hazard identification; dose-response assessment; exposure assessment; risk characterization Hazard identification; risk assessment; action planning
Enhanced problem formulation and scoping; planning and assessment; and risk management
Animal doses must be converted to human dose equivalents for risk assessment. When doing this, toxicologists and risk assessors must: Multiply the animal dose by the ratio of human to animal body weight raised to the 2⁄3 power Ensure they use the conversion method mandated or recommended by the regulatory agency most relevant to their efforts Multiply the animal dose by the ratio of human to animal body weight raised to the 3⁄4 power
Ensure they use the conversion method mandated or recommended by the regulatory agency most relevant to their efforts Toxicologists and risk assessors should check to ensure they use the approach mandated or recommended by the regulatory agency most relevant to their efforts.
The interdisciplinary core ("branches") of environmental toxicology includes: Environmental sciences; physics; toxicology; chemistry; biology Environmental sciences; engineering; toxicology; biology; computer and math Environmental sciences; computer and math; toxicology; biology; law Environmental sciences; biology; toxicology; chemistry; computer and math
Environmental sciences; biology; toxicology; chemistry; computer and math
There are only four types of tissues in the body. The type of tissue that is specialized to protect, absorb and secrete substances, detect sensations, covers every exposed body surface, and forms a barrier to the outside world is: Nerve tissue Epithelial tissue Connective tissue Muscle tissue
Epithelial tissue
According to EPA, a substance is classified as likely to be carcinogenic to humans when: There is strong evidence of human carcinogenicity Evidence is adequate to demonstrate potential carcinogenicity to humans, but not strongly enough to definitively classify as carcinogenic The weight of evidence suggests human carcinogenicity, but the data are determined not to be sufficient for a stronger conclusion Robust data lead to the conclusion that a substance is clearly carcinogenic to humans
Evidence is adequate to demonstrate potential carcinogenicity to humans, but not strongly enough to definitively classify as carcinogenic A substance is classified as likely to be carcinogenic to humans when evidence is adequate to demonstrate carcinogenic potential to humans but does not reach the weight of evidence for the descriptor Carcinogenic to Humans.
Phase 1
Expose or add functional groups
Which of the following factors that affect human and animal health is NOT correct? Fewer people in recent years live in close contact with wild and domestic animals Disruptions in environmental conditions and habitats provide new opportunities for diseases to pass to animals International travel and trade have increased, and diseases can spread quickly across the globe
Fewer people in recent years live in close contact with wild and domestic animals
The ability of the body to maintain relative stability and function even though drastic changes may take place in the external environment or in one portion of the body is known as: Physiology Homeostasis Toxicity
Homeostasis Homeostasis is the ability of the body to maintain relative stability and function even though drastic changes may take place in the external environment or in one portion of the body. In good health, homeostasis is maintained at all levels of the body hierarchy, including organs, tissues, cells, and biochemicals.
A cellular response in which there is an increase in the number of cells in a tissue is known as: Atrophy Hypertrophy Hyperplasia Metaplasia
Hyperplasia
A major component of exposure assessment involves: Identifying the exposure pathways Measuring the amount of a substance that is metabolized in the body Determining the amount of exposure that must be reduced to comply with the acceptable risk level
Identifying the exposure pathways Exposure pathways are key to exposure assessment because they identify the route a substance takes from its source to its end point, as well as how people can be exposed to the substance.
What exposure standards can be used to assign respiratory protection equipment? Immediately Dangerous to Life or Health (IDLH) Short Term Exposure Limits (STELs) Biological Exposure Indices (BEIs)
Immediately Dangerous to Life or Health (IDLH)
The initial stage in carcinogenesis in which there is an alteration of the DNA (mutation) is referred to as the: Progression stage Promotion stage Initiation stage
Initiation stage
Which of the following is NOT true about risk characterization? It involves predicting the frequency and severity of effects in exposed populations It determines the amount of exposure that must be reduced to comply with the acceptable risk level It integrates conclusions reached in hazard identification and exposure assessment It yields probabilities of effects likely to occur in humans exposed under similar conditions
It determines the amount of exposure that must be reduced to comply with the acceptable risk level Risk characterization involves predicting the frequency and severity of effects in exposed populations. It integrates conclusions reached in hazard identification and exposure to yield probabilities of effects likely to occur in humans exposed under similar conditions.
An increased cancer risk of 2.0 X 10^-6 means that: It is likely that two people out of one million will develop the specific type of cancer in their lifetime due to exposure to the chemical The xenobiotic for which the cancer risk assessment was performed is likely to cause cancer in two people on a yearly basis It is likely that two people out of one thousand will develop the specific type of cancer in their lifetime due to exposure to the chemical It is probable that two million people will develop cancer if they are continuously exposed to the chemical for life
It is likely that two people out of one million will develop the specific type of cancer in their lifetime due to exposure to the chemical An increased cancer risk of 2 times 10^-6 means two in a million people will likely develop the specific type of cancer in their lifetime due to exposure to the chemical.
The category of cells that routinely divide and replace cells that have a limited lifespan is known as: Labile cells Stable cells Permanent cells
Labile cells
Exposure standards are: Developed by chemical manufacturers Recommended maximum exposure levels which are voluntary and not legally enforceable Legally enforceable acceptable exposure levels or controls
Legally enforceable acceptable exposure levels or controls Exposure standards are legally enforceable acceptable exposure levels or controls resulting from Congressional or Executive mandate.
Most cancers are thought to be due to the following: Infections Food additives Lifestyle factors Pollution
Lifestyle factors
The primary cancer risk assessment model used by the EPA is known as the: Linearized Multistage Model (LMS) Probit Model Physiologically Based Pharmacokinetic Model (PB-PK)
Linearized Multistage Model (LMS) EPA uses the Linearized Multistage Model (LMS) to conduct its cancer risk assessments, producing the q1* that is used to predict cancer risk at a specific dose.
A body growth with the ability to metastasize or invade into surrounding tissues is known as a: Benign tumor Malignant tumor Hyperplasia
Malignant tumor
The EPA establishes exposure standards for natural and man-made contaminants in drinking water. These standards are called: Ambient Water Quality Criteria Maximum Contaminant Level Goals (MCLGs) Maximum Contaminant Levels (MCLs)
Maximum Contaminant Levels (MCLs) The EPA conducts risk assessments and issues Maximum Contaminant Levels (MCLs) for naturally-occurring and man-made contaminants in drinking water.
Primary product
May be eliminated from the body or undergo further biotransformation
An epidemiological study in which the individuals that make up the test cohort are identified according to past exposures is known as:
Retrospective cohort study
The Agency for Toxic Substances and Disease Registry (ATSDR) estimates levels for daily human exposure to chemicals that are likely to be without an appreciable risk of adverse effects for specified periods of exposure. These are known as: Minimal Risk Levels (MRLs) Maximum Contaminant Levels (MCLs) Reportable Quantities (RQs)
Minimal Risk Levels (MRLs) Minimal Risk Levels (MRLs) for noncancer toxic effects estimate the daily human exposures that are likely to be without an appreciable risk of adverse effects over a specific duration of exposure.
The organelle that produces nearly all (95%) of the energy required by the cell is the: Nucleolus Golgi apparatus Mitochondria Centrioles
Mitochondria
The type of neuron that relays information from the CNS to other organs is a: Motor neuron Sensory neuron Interneuron
Motor neuron
The two major categories of cells found in the nervous system are: Neurons and glial cells Astrocytes and microglia Schwann cells and oligodendrocytes
Neurons and glial cells The two major categories of cells found in the nervous system are neurons and glial cells. Neurons are the functional nerve cells directly responsible for transmission of information to and from the CNS to other areas of the body. Glial cells (also known as neuroglia) provide support to the neural tissue, regulate the environment around the neurons, and protect against foreign invaders.
In testing a pharmaceutical to comply with FDA requirements, the initial testing consists of:
Non-clinical laboratory studies
The primary goal of a Phase 1 clinical investigation is to:
Obtain information to design a more definitive Phase 2 clinical investigation
A substance in the body that contains covalently-bonded carbon and hydrogen is an: Organic compound Inorganic compound Element
Organic compound
One Health is a concept and strategy recognizing that the health of ________, ________, and __________ are all connected. People, plants, the environment People, animals, the environment People, animals, microbes
People, animals, the environment
The Occupational Safety and Health Administration (OSHA) develops legal standards for workplace exposure. These standards are called: Threshold Limit Values (TLVs) Recommended Exposure Limits (RELs) Permissible Exposure Limits (PELs)
Permissible Exposure Limits (PELs)
The exposure standard established by the EPA for the pesticide residue allowed to remain in or on each treated food product is called the: Pesticide tolerance for food use Reportable quantity of pesticides Maximum Contaminant Level (MCL)
Pesticide tolerance for food use The pesticide tolerance for food use standard established by the EPA specifies the pesticide residue allowed to remain in or on treated food products.
Determining the overall risk versus the benefit of a new pharmaceutical is part of:
Phase 3 clinical investigation
An increase in skeletal muscle cells in athletes due to exercise and increased metabolic demand is an example of: Pathological adaptation Physiological adaptation
Physiological adaptation
According to the European Commission, ignoring uncertainty may lead to: Great decision-making Poor decision-making Effective risk communication Use of the most accurate knowledge available
Poor decision-making
There are several different types of cellular organelles. The very small structures (fixed to the endoplasmic reticulum or free within the cytoplasm) that consist of RNA and proteins, and function in protein synthesis, are: Nucleus Peroxisomes Lysosomes Ribosomes
Ribosomes
What is the difference between primary National Ambient Air Quality Standards (NAAQS) and secondary NAAQS? Primary NAAQS relate to public welfare (for example, crops, animals, and structures); secondary NAAQS set limits to protect public health Primary NAAQS set limits to protect public health; secondary NAAQS relate to public welfare Primary NAAQS are legally enforceable; secondary NAAQS are not
Primary NAAQS set limits to protect public health; secondary NAAQS relate to public welfare Primary NAAQS set limits to protect public health. Secondary NAAQS relate to public welfare, such as crops, animals, and structures.
Risk is the: Capability of a substance to cause an adverse effect Weighing of possible alternatives and selecting the most appropriate regulatory actions Probability that a hazard will occur under specific exposure conditions
Probability that a hazard will occur under specific exposure conditions
Under the Delaney Clause of 1958, the FDA: Required physicians to strictly adhere to exposure standards for pharmaceuticals Prohibited the addition of any substance to food that has been shown to induce cancer in humans or animals Authorized the addition of potentially carcinogenic substances to food as long as the concentration is at 0.05 ppm or less
Prohibited the addition of any substance to food that has been shown to induce cancer in humans or animals The Delaney Clause prohibits adding any substance to food that has been shown to induce cancer in humans or animals. The lowest level of concern for an additive used at 0.05 ppm is irrelevant in this case.
To maintain homeostasis, the body reacts to an abnormal change (induced by a toxin, biological organism, or other stress) and makes certain adjustments to counter the change (a defense mechanism). The component of the homeostasis process which detects the change in the environment is known as the: Effector Stimulus Receptor
Receptor A receptor is the site within the body that detects or receives the stimulus, senses the change from normal, and sends signals to the control center.
Exposure standards for pharmaceuticals are: Issued by the U.S. Food and Drug Administration (FDA) Developed by the Environmental Protection Agency Recommended guidance developed by the U.S. Food and Drug Administration (FDA)
Recommended guidance developed by the U.S. Food and Drug Administration (FDA) The FDA does not issue exposure standards for drugs, but rather approves a New Drug Application containing guidance for usage and warnings that the manufacturer must provide to physicians and others.
Exposure guidelines are: Developed by chemical manufacturers Recommended maximum exposure levels which are voluntary and not legally enforceable Legally enforceable acceptable exposure levels or controls
Recommended maximum exposure levels which are voluntary and not legally enforceable Exposure guidelines are recommended maximum exposure levels that are voluntary and not legally enforceable.
Which of the following is NOT true about communicating risk to a community about exposures and health effects? Results should be communicated in a format and a manner that subjects can readily understand Results do not need to be communicated in a format and a manner that subjects can readily understand Communications should be tailored to the project and should contain what people really need to know Researchers and others can learn from studying good and bad risk communication efforts
Results do not need to be communicated in a format and a manner that subjects can readily understand
Minimal Risk Levels (MRLs) are derived: Similarly to deriving the RfD, but with a potentially lower uncertainty factor By multiplying the cancer slope factor by the lowest exposure dose By multiplying the LOAEL by safety factors
Similarly to deriving the RfD, but with a potentially lower uncertainty factor The MRL is calculated much like the RfD, except that the uncertainty factors of 10 may be lower (2 or 3), based on scientific judgment.
Which of the following statements is correct? The concept of dose-response relationships is easily understood by the public The public and toxicologists tend to agree about the risks of chemicals Technical judgments of toxicologists have been found to not be associated with factors such as their type of employment (for example, academia, government of industry, gender, and age) Technical judgments of toxicologists have been found to be associated with factors such as their type of employment (for example, academia, government of industry, gender, and age)
Technical judgments of toxicologists have been found to be associated with factors such as their type of employment (for example, academia, government of industry, gender, and age)
What are the two basic types of synapses? Neuro-muscular and neuro-glandular CNS and PNS synapses Those between two neurons and a neuron and effector
Those between two neurons and a neuron and effector The two basic types of synapses are those between two neurons and those between a neuron and effectors, such as muscle cell or gland. The major difference in the two basic types is that the neurotransmitting chemical between a neuron and muscle cell is acetylcholine whereas there are several other types of neurotransmitting chemicals involved between neurons, depending on where in the nervous system the synapse is located.
Groups of cells with similar structure and function are known as: Tissues Organs Organ systems
Tissues Tissues are groups of cells with similar structure and function. There are only four types of tissues: epithelial tissue, connective tissue, muscle tissue, and nerve tissue.
Hydrophilic
Toxicant is converted to water-soluble in order to be safely eliminated from the body
Lipophilic
Toxicant starts as lipid-soluble
The cellular gene which is present in most normal cells and serves as a balance to the genes for tumor expression is known as a: Tumor suppressor gene Oncogene Proto-oncogene
Tumor suppressor gene
Consumer exposure standards are developed for hazardous substances and articles by the: U.S. Food and Drug Administration (FDA) U.S. Consumer Product Safety Commission (CPSC) General Product Safety Directive (GPSD)
U.S. Consumer Product Safety Commission (CPSC) The U.S. Consumer Product Safety Commission (CPSC) is charged with protecting the public from unreasonable risks of injury or death associated with the use of the consumer products under its jurisdiction.
The movement of substances in environmental media is primarily predicted by: Tagging substances with radioactive tracers and measuring radioactivity at various times and locations within the environmental media Using exposure models to derive scientific estimates Performing actual measurements of exposure pathways
Using exposure models to derive scientific estimates Since actual measurements of exposures are often unavailable, exposure models may be used.
Can quantitative read-across be used to determine the value of an endpoint, such as dose-response relationship?
Yes Quantitative read-across can lead to a measurable value for an endpoint, such as a dose-response relationship.
