How Environmental Contaminants Enter the Body Review of Worksheet Questions

1. Respiratory Structures Flow Chart

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) O 2 diffuses from the alveoli into the capillaries (air we breath in) CO 2 diffuses from the capillaries into the alveoli (then we breathe out)

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

Cilia and Mucus lining our airways (trachea)

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

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

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

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.

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

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

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)

13 & 15 Defences (skin) 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

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

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 CO 2 in it from our cells back to our lungs

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.

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

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