 Three different ways:  Inhalation (breathing)  Ingestion (eating)  Absorption through skin

 Breath in through nose and mouth Pharynx Trachea Bronchial Tubes Lungs

 Diaphragm contracts lungs expand air sucked in  Diaphragm relaxes air forced up and out

 Bronchial tubes (bronchus) bronchioles Alveoli capillaries Alveoli = site of gas exchange Oxygen (O 2 ) Carbon Dioxide (CO 2 )  Carried to cells in body

 Smoke, bacteria, dust  Nasal passage ways & bronchial tubes = mucus and cilia  Mucus = traps inhaled particles  Cilia = move particles in wave like motions to be expelled through sneezing and coughing - Can only defend against low doses ~ no defence against VOC’s and pesticides

 Ingestion = process of eating and drinking  Digestion = break down of food into smaller pieces in order to absorb chemical nutrients  Carbohydrates  Proteins  Fats  Vitamins and Minerals

 Starts in mouth with chewing  Teeth = break up food into smaller pieces  Saliva = moistens and breakdown food  Swallow food esophagus stomach small intestine (most nutrients absorbed)  Mixed with digestive substances from liver and pancreas  Liver = bile (breakdown and absorb fat)  Pancreas = very important organ in digestion - breakdown carbohydrates, proteins, fats

 Intestinal walls lined with villi  other side = capillaries  Nutrients absorbed through small intestine walls into circulatory system and distributed to rest of cells in body  Food not absorbed in small intestine passed to large intestine = water absorbed, compacted into feces

 Vomiting  Contents from middle of intestine up forced out through mouth  Liver  Filters blood ~ removes poisons that get across villi

 Skin = largest organ; first line of defence against outside world  Makes Vitamin D with sunlight ~ calcium

Structure:  Epidermis Dermis Subcutaneous

 Epidermis:  Two layers (top = dead cells, bottom = new cells)  Dermis:  Contains nerve endings and capillaries, sweat glands  Subcutaneous  Fat cells

 Keeps out water and contaminants  Can absorb chemicals in cleaning products and in workplace, as well as oils, tars, alcohols, pesticides  Harm layers of skin  Get into capillaries and carried to cells of body

 Heart, veins, arteries, capillaries  Carries blood to cells of body and transports nutrients and wastes  Nutrients = carbohydrates, proteins, fats, vitamins, minerals  Wastes = carbon dioxide, water, heat

 Fights pathogens when skin is wounded (white blood cells)  Contaminants can get into blood through wounds from sharp objects, insect and animal bites  Carries contaminants to organs, tissues, systems