Transcript Document
31.1 Pathogens and Human Illness Describe this picture. 31.1 Pathogens and Human Illness Sponge #1 1. What do you think the white blood cell is doing in this picture? 2. Why do you not get sick EVERYTIME disease causing germs invade your body? White blood cell E. Coli (bacteria) 31.1 Pathogens and Human Illness Sponge #1 1. What do you think the white blood cell is doing in this picture? The white blood cell is attacking the invader 2. Why do you not get sick EVERYTIME disease causing germs invade your body? The white blood cells attack and destroy invaders before you get ill. They protect you. White blood cell E. Coli 31.1 Pathogens and Human Illness KEY CONCEPT Germs cause many diseases in humans. 31.1 Pathogens and Human Illness • Diseases caused by germs, such as the E. Coli bacteria can be fatal (death) • 1330-1352, the bacteria that caused the “Black Death” or the Plague originated from fleas on rats – Has killed approx. 100 MILLION people – New diseases - HIV SARS Avian Flu (bird flu) Swine Flu 31.1 Pathogens and Human Illness • Germ theory proposes that microorganisms cause diseases. – led to rapid advances in understanding disease – Can be infectious (polio, flu), caused by germs – or noninfectious (cancer, heart disease) caused by genes or lifestyle 31.1 Pathogens and Human Illness • Disease-causing agents are called pathogens. • What would happen if pathogens were eliminated? – We wouldn’t get sick 31.1 Pathogens and Human Illness There are different types of pathogens. • Bacteria are single-celled organisms. – cause illness by destroying cells – release toxic chemicals – – – – Exs: E. Coli Salmonella “Food Poisoning” 31.1 Pathogens and Human Illness • Viruses are disease-causing strands of DNA or RNA that are surrounded by a protein coat. – Take over a healthy cell – Force cells to produce more of the virus – Smaller than bacteria – Exs: – HIV – – – – Influenza Herpes *Common Cold AIDS 31.1 Pathogens and Human Illness • Fungi can be multicellular or single-celled. – take nutrients from host’s cells – occur in warm and damp places Ex: Athlete’s foot, yeast, mold 31.1 Pathogens and Human Illness • Protozoa are single-celled organisms – Prey on other cells – use host cells to complete their life cycles – take nutrients from host cell – Ex: Malaria, dysentery 31.1 Pathogens and Human Illness • Parasites are multicellular organisms. – grow and feed on a host – possibly kill the host Ex: Heart worm Round worm Elephantiasis- mosquitos 31.1 Pathogens and Human Illness • Vectors any person or animal that carries and transmits a pathogen to another living organism. • Direct contact requires touching an infected individual. Includes: – kissing – sexual intercourse – hand shaking – bite tick Ex: Lime Disease- ticks Malaria- mosquito West Nile Virus- mosquito Rabies- rabid animal HIV- infected person 31.1 Pathogens and Human Illness Pathogens can enter the body in different ways. • Direct contact require an infected person or animal to physically touch a healthy person Ex: Rabies, HIV • Indirect contact does not require touching an infected individual. – touching an infected surface – breathing in infected air Ex: SARS Tuberculosis 31.1 Pathogens and Human Illness • Different pathogens cause common infectious diseases. 31.1 Pathogens and Human Illness Bacteria Videos Beneficial Bacteria • Types • Functions • Examples Harmful Bacteria • Types • Functions • Examples Take notes on the two videos 31.1 Pathogens and Human Illness Beneficial Bacteria • Decomposers – Break down dead material • Soil – Makes it fertile so plants can grow • Intestines – Aids in digestion – Produces vitamins • Food – Cheese, sour cream, yogurt • Medicine– help fight diseases • Sewage Treatment • Oil spills Harmful Bacteria • Take over ponds, etc. – Kills existing life • Food – Grows on food (spoils) • Mouth – Feed on food in between teeth - Must brush and floss • Infect – Open sores • Difficult to kill – May have a slippery outer capsule 31.2 Immune System Homework Draw a double-bubble map comparing and contrasting bacteria and viruses (pg. 942 & notes) 31.2 Immune System Smaller than Bacteria Single- celled Have a protein coat Pathogens HIV E. Coli Bacteria Release toxic chemicals microscopic Infectious Viruses Flu Force cells to produce more virus Common cold Larger than viruses