How Environmental Contaminants Enter the Body

1. How Environmental Contaminants Enter the Body Review of Worksheet Questions

3. 1. Respiratory Structures Flow Chart

4. 2. Gas Exchange • Capillaries are very fine blood vessels passing through the alveoli (tiny air sacs in our lungs). Capillaries have very thin walls (1 cell thick) • O2 diffuses from the alveoli into the capillaries (air we breath in) • CO2 diffuses from the capillaries into the alveoli(then we breatheout)

6. 3. Mucus and Cilia • Cells lining the nasal passages, trachea and upper bronchial tubes produce mucus and have moving hair-like projections called cilia. • Mucus traps particles • Cilia move particles toward the throat and nose • We sneeze/cough etc

8. Cilia and Mucus lining our airways (trachea)

9. Cannot defend against • VOCs (volatile organic compounds) - VOCs are any chemicals that easily evaporate into the air (e.g. from plastics, furniture, paints etc.) • Pesticides

10. 4. Food Entering Stomach • A muscular organ • Mechanical digestion – churning • Chemical digestion – gastric juice made of hydrochloric acid and enzymes (which break down food chemicals like proteins) • Turns solid food into liquid (chyme) before it passes into the small intestine

13. 6. Organs associated with the small intestine • Liver, gall bladder, pancreas provide bile and enzymes to the small intestine • Break food up further (chemical digestion) – molecules small enough to cross from the stomach into the bloodstream

15. 7 & 8 Food Absorption • Movement of nutrients through the stomach lining into capillaries • Mostly takes place in the small intestine Nutrients get transported to our cells by the blood in our arteries and veins.

16. 9. Surface Area • Small projections lining the intestine called villi – very thin walled – increase surface area for absorption

17. 10. Large Intestine • Absorbs water and compacts leftover waste for elimination

18. 11 & 12 Defences (Digestive) • Liver – filters the blood if contaminants have crossed the villi from our intestines into our blood (e.g. drugs, alcohol) • Vomiting – contents from about the middle of the small intestine and up are forcefully ejected – a way we get rid of poisons and pathogens (e.g. viruses/bacteria)

19. 13 & 15 Defences (skin) • Keeps out insects, pathogens, heat/cold, wet/dry. • However some substances can be absorbed such as oils, tars, alcohols, cleaning products (often acids/bases), pesticides

20. 14. Skin layers • Epidermis – layer of dead cells that slowly wear off • Dermis – sebaceous / oil glands keeps skin moist, capillaries and nerve endings, sweat glands keep body cool • Subcutaneous layer – contain fat cells for insulation

22. 16. Arteries and Veins • Arteries carry blood that has oxygen in it from our heart/lungs to the rest of our body • Veins carry blood with CO2 in it from our cells back to our lungs

23. 17. Blood • Transport of gases (O2 and CO2) between our lungs and our cells. • Transport of nutrients from our intestine to our cells. • Transport of other wastes to our liver and kidneys for processing.

24. Kidneys and Excretion • 2 bean-shaped organs, each about the size of a fist. • Kidneys are filters - 200 liters of blood goes through your kidneys each day - 2 liters of waste products and extra wateris produced. • Wastes and extra water become urine, which flows to the bladder through tubes called ureters. The bladder stores urine until releasing it.

26. Kidneys act as waste removal systems • Environmental toxins can build up in the kidneys if there is an excess that they are trying to process