How Environmental Contaminants Enter the Body

Review of Worksheet Questions

1. Respiratory Structures Flow Chart

2. Gas ExchangeCapillaries 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)

3. Mucus and CiliaCells lining the nasal passages,

trachea and upper bronchial tubes produce mucus and have moving hair-like projections called cilia.

Mucus traps particlesCilia move particles toward the

throat and noseWe sneeze/cough etc

Cilia and Mucus

lining our airways (trachea)

Cannot defend againstVOCs (volatile organic

compounds)

- VOCs are any chemicals that easily evaporate into the air (e.g. from plastics, furniture, paints etc.)

Pesticides

4. Food Entering StomachA muscular organMechanical digestion – churningChemical 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 intestineLiver, 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 AbsorptionMovement of nutrients through

the stomach lining into capillariesMostly takes place in the small

intestine

Nutrients get transported to our cells by the blood in our arteries and veins.

9. Surface AreaSmall projections lining the

intestine called villi – very thin walled – increase surface area for absorption

10. Large IntestineAbsorbs 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)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 layersEpidermis – layer of dead cells

that slowly wear offDermis – 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 VeinsArteries carry blood that has oxygen in it

from our heart/lungs to the rest of our bodyVeins carry blood with CO2 in it from our

cells back to our lungs

17. BloodTransport 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 Excretion2 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 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