Human Health and Environmental Toxicology Chapter 7

Learning Objectives Research and answer the fifteen Learning Objectives from chapter 7. Chapter 7 Bonus

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 (years) Infant Mortality (# deaths up to age one per 1,000 live births) Japan Source: U.S. Census Bureau, International Database Switzerland Sweden Mozambique Zimbabwe Angola

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 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 programsDue to 1950s vaccination programsReemerging – In cases worldwide– In cases worldwide (6 countries)(6 countries) (Nigeria, India, Pakistan, Afghanistan and Egypt.. Nigeria 789 cases in 2004(Nigeria, India, Pakistan, Afghanistan and Egypt.. Nigeria 789 cases in 2004 Why so many?Why so many? Nigerian state of Kano objectionsNigerian 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 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

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* *Pituitary* Parathyroid *Thyroid* thymus *Adrenal* *Pancreas,* “Islets of Langerhans” Ovaries Testes

The Endocrine Matching Game Gland Hormone Secreted Hormone Function TargetCell Anterior Pituitary Stimulates thyroid Thyroxin Increases blood glucose Heart, lungs, blood vessels, eyes

The Endocrine Matching GameGland Hormone Secreted Hormone Function TargetCell Anterior Pituitary GHElongate bonesBones Anterior Pituitary TSHStimulates thyroidThyroid ThyroxinControls metabolismBody cells PancreasGlucagonIncreases blood glucoseLiver and muscle cells AdrenalAdrenalinePrepare for fight or flightHeart, 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 LD 50 (dose at which 50% of test subjects die due to exposure)

Determining Health Effects of Environmental Pollution Lethal Dose-50% (LD 50 )

Determining Health Effects of Environmental Pollution Effective Dose-50% (ED 50 ) – 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