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Chapter 14 Toxicology
Objectives:Know what the endocrine system is.Know what hormones are.Know the four major types of chemical toxins.Know what endocrine disruptors are.Understand the problem of BPA
Toxins
• There are many different types of toxins that found in the environment.
Types of Toxins
• Carcinogens – substances or types of radiation that cause cancer
• Mutagens – substances that cause genetic mutations in an organisms DNA (Damage DNA)• Mutagens may cause cancer or
birth defects
• Teratogens – substances that affect the development of embryos
Types of Toxins
• Endocrine disruptors – substances that interfere with the endocrine system
Polycyclic Aromatic Hydrocarbons (PAH)
• PAHs are carcinogens
• PAHs are a concern because they are persistent. (They do not leave the environment easily)
• Individual PAHs vary in behavior.• Some can turn into a vapor in the
air very easily.
• Most do not break down easily in the water.
PAHs
Mutagens
Teratogens
• Thalidomide– prescribed to pregnant women in the 1950s as a sleeping pill and to help with morning sickness
Endocrine Disruptors
• Endocrine disruptors are becoming the most important and potentially frightening type of toxin
• They can affect the body at the most minute amounts.
• They hi-jack the body’s most powerful signaling system
• 93% of Americans have detectable levels in their urine.
BPA
• Bisphenol A - pronounced BIS phee nawl
• Bisphenol A (BPA) is a chemical that has found almost universal uses.
• BPA has allowed for the production of strong and clear plastics.
These are made with BPA
BPA is Ubiquitous
What does BPA do?
• Bisphenol A at the molecular level looks like estrogen.
• Estrogen is primarily a female sex hormone, though males do have it though it much smaller amounts.
• BPA has been linked to cancers of the breast, prostate, and testicles to name a few.
• Studies have linked it to obesity, drug addiction, and thyroid problems.
• Reproductive capacity may also be affected.
BPA and Lab Animals
Endocrine Disruptors
The Endocrine System
• The endocrine system is a group of organs and associated structures that regulate bodily functions such as cell growth.
• The major organs of the endocrine system are:• hypothalamus• pituitary gland• thyroid• parathyroid• adrenal glands• pineal body• reproductive glands (ovaries and testes)• pancreas
Hormones
• Hormones are the chemical messengers that are released from one cell and affect a different cell in another area of the body.
• Examples of hormones include• ADH (antidiuretic hormone)• growth hormone• Insulin • Testosterone• Estrogen• Adrenaline
How Endocrine Disruption Works
How Endocrine Disruption Works
What is being done
• Canada has banned the sale of BPA containing products
• The US has only banned it from baby bottles• It can still be found in bowls for
toddlers, cans of infant formula, and other food packages.
• Endocrine disruptors are also found in the clothing of infants and toddlers• Flame retardants are known
endocrine disruptors