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Chapter 7
Human Health
and
Environmental
Toxicology
Chapter 7 Bonus
Research and answer the fifteen
Learning Objectives from chapter 7.
Do Now:
Life Expectancy / Infant Mortality
Why are life expectancies and infant
mortality rates in highly developed and
developing countries so different?
Do Now: ANSWERS
Life Expectancy / Infant Mortality

there are significant differences in
nutrition, medical (particularly infant)
care, and even in workplace safety
between these two groups of nations.
Human Health
Overall human health best
assessed by:
1) Life expectancy (years)
2) Infant mortality (# deaths up to
age one per 1,000 live births)
Life Expectancy / Infant Mortality
Selected countries, 2004 data
Life Expectancy
Infant Mortality
(years)
(# deaths up to age one
per 1,000 live births)
Japan
81.2
3.3
Switzerland
80.4
4.4
Sweden
80.4
2.8
Mozambique
40.3
130.8
Zimbabwe
36.7
60.7
Angola
36.6
191.2
Source: U.S. Census Bureau, International Database
Do Now:
How do health care professionals define
obesity?
Identify two health risks associated with
obesity.
Source: U.S. Census Bureau, International Database
Do Now: ANSWERS
Obesity is defined by calculating the body
mass index.
To calculate the BMI, multiply your weight by
740, then divided that number by your
height in inches, squared. If this number is
over 30 you are considered obese. Stroke,
heart disease, kidney failure and type 2
diabetes are health risks related to obesity.
Source: U.S. Census Bureau, International Database
Do Now: ANSWERS
18.5-24.9
Source: U.S. Census Bureau, International Database
Health Issues in Highly Developed
Countries
Leading causes of death in US:
Cardiovascular diseases, cancer, & chronic
obstructive pulmonary disease
Linked to . . .
Obesity
Health Issues in Developing Nations
Malnutrition, unsafe water, and poor
sanitation
Leads to . . .
Numerous infectious
diseases
Compounded by poor
healthcare, leads to . . .
Lowered life
expectancy
Eradication and then Reemerging
Diseases
Polio Eradication:
•Due to 1950s vaccination programs
Reemerging
•–In 2004 1230 cases worldwide
•(6 countries)
•(Nigeria, India, Pakistan, Afghanistan
and Egypt.. Nigeria 789 cases in 2004
•Why so many?
•Nigerian state of Kano objections
Emerging v. Reemerging Diseases
Emerging –
Not previously observed within humans:
AIDS, Lyme disease, West Nile virus,
Creutzfeld-Jakobs disease (MC)
Reemerging –
Existed previously, becoming
more common again:
Tuberculosis, Yellow fever,
Malaria
Why? Impoverished regions,
antibiotic resistance
Environmental Pollution & Disease
Persistence
• Degradation of synthetic pesticides is
slow. WHY do so many remain in soil +
water for years?
– Novel chemical structures (new to nature)
– Decomposers have not evolved to degrade
them
Bioaccumulation
•Natural substances commonly
recycle in living organisms.
Intake = Output (no long term
accumulation)
•Synthetic substances typically not
metabolized.
Intake, with little output =
accumulation (typically in fat)
Biomagnification
Biomagnification
Example: Effect of DDT on bald eagles
Aves Reproductive System
The ovaries appear like a bunch of
grapes and in an adult will contain
five to six developing egg yolks.
The oviduct is divided into five
regions:
funnel or infundibulum, magnum
where albumen is secreted,
isthmus which secretes the shell
membranes,
uterus or shell gland,
the vagina which connects to the
cloaca.
Chicken eggs are incubated about
21 days before hatching.
Aves
Reproductive
System
Endocrine System
Your endocrine system is a
collection of glands that
produce hormones that
regulate your body's
growth, metabolism, and
sexual development and
function.
The hormones are released
into the bloodstream and
transported to target
tissues and organs
throughout your body.
The Endocrine System
is responsible for chemical regulation.
Stimuli may cause certain glands to
secrete chemical messengers known as
hormones.
These hormones cause other parts of the
body to respond. Target Cell
Endocrine System
Hormones- chemical messengers that are
secreted by glands and diffuse directly
into the bloodstream
hormones regulate a wide range of
activities in humans
Pineal
*Hypothalamus*
Parathyroid
*Pituitary*
*Thyroid*
thymus
*Adrenal*
*Pancreas,*
“Islets of
Langerhans”
Ovaries
Testes
The Endocrine Matching
Game
Gland
Hormone Hormone
Secreted Function
Target
Cell
Anterior
Pituitary
Stimulates thyroid
Thyroxin
Increases blood
glucose
Heart, lungs,
blood
vessels, eyes
http://www.last.fm/music/Red+Hot+Chili+Peppers/_/Give+It+Away
The Endocrine Matching Game
Gland
Hormone
Secreted
Hormone
Function
Target
Cell
Anterior
Pituitary
GH
Elongate bones
Bones
Anterior
Pituitary
TSH
Stimulates thyroid
Thyroid
Thyroid
Thyroxin
Controls metabolism
Body cells
Pancreas
Glucagon
Increases blood glucose Liver and
muscle cells
Adrenal
Adrenaline
Prepare for fight or flight Heart, lungs,
blood vessels,
eyes
(2) Pituitary Gland
Located at the base of the brain
Called the “master gland” because
it controls the activities of other
glands
Secretes three major hormones:
GH, TSH, and FSH
The Over Secretion of Growth
Hormone
7’4”, 500lbs
Do Now:
Which
endocrine
gland is the
most important
and why?
Dwarfism
Herve Villechaize
Growth Hormone (GH)
This hormone controls the growth
of the body by stimulating the
elongation of bones
Thyroid Stimulating
Hormone (TSH)
Stimulates the thyroid gland to
produce its hormone thyroxin
Follicle
Stimulating
Hormone
(FSH)
Stimulates
the
activities of
the ovaries
and testes
(3) Thyroid Gland
Located in the neck
below the larynx and
in front of the
trachea
This gland secretes
thyroxin which
contains iodine
(3) Thyroid Gland
Do Now:
Using your HW
identify the
hormones
numbered 1+2.
What is the reason
for the “+” and “-”
symbols.
1. _____
2. _____________
Do Now: ANSWERS
1 Thyroid Stimulating
Hormone (TSH)
2. Thyroxine
“+” positive feedback
Stimulates
“-” negative feedback
(shuts off)
TSH
Thyroxin
Regulates the rate of metabolism in the body and is
essential for normal physical and mental development
Secretion of thyroxin is regulated by TSH, which is
secreted by the pituitary gland
Lack of iodine in the diet will lead to lack of thyroxin
secretion. This produces enlargement of the thyroid
gland and is called Goiter
Goiter- is the result of iodine deficiency in the diet
Iodine Needed for
Thyroxin
Goiter- is the result of iodine deficiency in the diet
Iodine
Needed for
Thyroxin
Endocrine Disruptors
• Chemicals that alter hormone production.
Ex: PCBs, dioxins, lead, mercury, DDT
• Hormones have their affect at low doses.
• Endocrine disruptors act similarly.
Endocrine Disruptors
Example: American alligators and DDT spill
Determining Health Effects of
Environmental Pollution
Toxicant –
Chemical that induces adverse response at
a certain dose.
Toxicity of a chemical is assessed by
determining its LD50
(dose at which 50% of test subjects die due
to exposure)
Determining Health Effects of
Environmental Pollution
Lethal Dose-50% (LD50)
Determining Health Effects of
Environmental Pollution
Effective Dose-50% (ED50) –
Dose that induces 50% of test subjects to
have some type of effect
Dose response curve –
Determining Health Effects of
Environmental Pollution
Children and
chemical exposure
Determining Health Effects of
Environmental Pollution
Identifying Cancer-Causing Substances
•
Carcinogen –
Environmental agent known to induce
cancer.
•
Chemicals commonly tested with rats
but, is the dose equivalent?
•
Can you extrapolate the results to
humans?
Determining Health Effects of
Environmental Pollution
Chemical Mixtures
•
Most studies examine effect of single
chemical exposure.
•
What happens when exposed to
multiple chemicals?
•
Additive effect?
•
Synergistic effect?
•
Antagonistic effect?
Ecotoxicology
• Dilution paradigm –
“the solution to pollution is dilution”
• Boomerang paradigm –
“what you throw away can come back and
hurt you”
Ecotoxicology
Case in Point:
The Ocean and Human
Health
Decision Making and Uncertainty
Risks:
Decision Making and Uncertainty
Risk assessment:
Low
High
Decision Making and Uncertainty
Risk assessment:
Decision Making and Uncertainty
Ecological risk assessment:
Extends steps of risk assessment
to the impact on all plants, animals,
and other organisms in an area.
Decision Making and Uncertainty
Ecological risk assessment example:
Dams on Snake River
Decision Making and Uncertainty
Cost-Benefit Analyses
Cost
Benefit