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