HSCI 204 MODULE 10 EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026
Define environmental neurotoxicants - Answers Environmental neurotoxicants are chemicals that
damage the nervous system especially the developing brain.
Explain main idea of environmental neurotoxicants - Answers Small effects on individual brain
function can lead to large impacts at the population level.
List key environmental disasters that showed neurotoxicity - Answers Examples include lead
poisoning Minamata mercury poisoning arsenic contaminated milk and PCB exposure.
What did Minamata disease show - Answers It showed that mercury exposure can cause severe brain
damage especially in infants exposed during pregnancy.
Why is the developing brain vulnerable - Answers The brain is rapidly developing the blood brain
barrier is immature and neurons are forming and connecting making it highly sensitive to toxins.
List reasons children are more vulnerable to toxins - Answers Reasons include rapid development
immature blood brain barrier and critical windows of exposure.
Define windows of vulnerability - Answers Windows of vulnerability are periods such as prenatal
development when exposure has stronger and often permanent effects.
Explain why timing of exposure matters - Answers Exposure during critical development stages can
disrupt normal brain formation leading to long term damage.
List mechanisms of neurotoxicity - Answers Mechanisms include neuron damage disruption of
neurotransmission endocrine disruption and epigenetic changes.
Explain how lead affects the brain - Answers Lead disrupts neurotransmission and interferes with
normal brain development.
Explain how mercury affects the brain - Answers Mercury damages neurons and impairs brain
development.
Explain how BPA and PCBs affect the brain - Answers They act as endocrine disruptors altering
hormone signaling and affecting brain development.
Define epigenetics - Answers Epigenetics refers to changes in gene expression without altering DNA
sequence often influenced by environmental exposures.
List common neurotoxic exposures - Answers Common exposures include lead mercury arsenic PCBs
DDT BPA and pesticides.
How are exposures measured in studies - Answers Exposures are measured using biomarkers such as
blood urine or hair samples.
Define biomarker - Answers Biomarkers are measurable substances in the body used to estimate
exposure to chemicals.
Explain effects of toxins on IQ - Answers Exposure to chemicals like lead mercury and PCBs is
associated with reduced IQ even at low levels.
Why is low level exposure important - Answers Even small reductions in IQ across a population can
lead to large societal impacts.
Explain population impact of IQ shifts - Answers A small decrease in average IQ increases the number
of individuals with low IQ and decreases those with high IQ leading to large societal consequences.
Define no safe level concept - Answers Some toxins like lead have no safe exposure level meaning
any exposure can cause harm.
Explain dose response for neurotoxins - Answers Dose response may be linear or supralinear meaning
effects can occur even at low doses.
Define supralinear dose response - Answers A supralinear response means that small increases at low
exposure levels produce relatively large effects.
Explain prevention paradox in neurotoxicity - Answers Most harm comes from large numbers of
people with low to moderate exposure rather than a few highly exposed individuals.
Why is population wide prevention needed - Answers Because reducing exposure across the whole
population has the greatest impact on overall health.
Define ADHD - Answers ADHD is a neurodevelopmental disorder involving attention deficits
hyperactivity and impulsivity.
List environmental risk factors for ADHD - Answers Strong links include lead and tobacco while
possible links include pesticides BPA and air pollution.
Define autism - Answers Autism is a neurodevelopmental condition influenced by genetic and
environmental factors.
Define environmental neurotoxicants - Answers Environmental neurotoxicants are chemicals that
damage the nervous system especially the developing brain.
Explain main idea of environmental neurotoxicants - Answers Small effects on individual brain
function can lead to large impacts at the population level.
List key environmental disasters that showed neurotoxicity - Answers Examples include lead
poisoning Minamata mercury poisoning arsenic contaminated milk and PCB exposure.
What did Minamata disease show - Answers It showed that mercury exposure can cause severe brain
damage especially in infants exposed during pregnancy.
Why is the developing brain vulnerable - Answers The brain is rapidly developing the blood brain
barrier is immature and neurons are forming and connecting making it highly sensitive to toxins.
List reasons children are more vulnerable to toxins - Answers Reasons include rapid development
immature blood brain barrier and critical windows of exposure.
Define windows of vulnerability - Answers Windows of vulnerability are periods such as prenatal
development when exposure has stronger and often permanent effects.
Explain why timing of exposure matters - Answers Exposure during critical development stages can
disrupt normal brain formation leading to long term damage.
List mechanisms of neurotoxicity - Answers Mechanisms include neuron damage disruption of
neurotransmission endocrine disruption and epigenetic changes.
Explain how lead affects the brain - Answers Lead disrupts neurotransmission and interferes with
normal brain development.
Explain how mercury affects the brain - Answers Mercury damages neurons and impairs brain
development.
Explain how BPA and PCBs affect the brain - Answers They act as endocrine disruptors altering
hormone signaling and affecting brain development.
Define epigenetics - Answers Epigenetics refers to changes in gene expression without altering DNA
sequence often influenced by environmental exposures.
List common neurotoxic exposures - Answers Common exposures include lead mercury arsenic PCBs
DDT BPA and pesticides.
How are exposures measured in studies - Answers Exposures are measured using biomarkers such as
blood urine or hair samples.
Define biomarker - Answers Biomarkers are measurable substances in the body used to estimate
exposure to chemicals.
Explain effects of toxins on IQ - Answers Exposure to chemicals like lead mercury and PCBs is
associated with reduced IQ even at low levels.
Why is low level exposure important - Answers Even small reductions in IQ across a population can
lead to large societal impacts.
Explain population impact of IQ shifts - Answers A small decrease in average IQ increases the number
of individuals with low IQ and decreases those with high IQ leading to large societal consequences.
Define no safe level concept - Answers Some toxins like lead have no safe exposure level meaning
any exposure can cause harm.
Explain dose response for neurotoxins - Answers Dose response may be linear or supralinear meaning
effects can occur even at low doses.
Define supralinear dose response - Answers A supralinear response means that small increases at low
exposure levels produce relatively large effects.
Explain prevention paradox in neurotoxicity - Answers Most harm comes from large numbers of
people with low to moderate exposure rather than a few highly exposed individuals.
Why is population wide prevention needed - Answers Because reducing exposure across the whole
population has the greatest impact on overall health.
Define ADHD - Answers ADHD is a neurodevelopmental disorder involving attention deficits
hyperactivity and impulsivity.
List environmental risk factors for ADHD - Answers Strong links include lead and tobacco while
possible links include pesticides BPA and air pollution.
Define autism - Answers Autism is a neurodevelopmental condition influenced by genetic and
environmental factors.
