Chapter 10

• pathogens are microorganisms that cause disease in humans or animals
• a transmissible disease is a disease that is transferrable from one host to another
• transmission is the movement of a pathogen from one host to another
• a host is an organism where pathogens breed and live
• toxin is a toxic substance that damages cells
• an infection is the entry of pathogens in the host
• symptoms are the features or signs you get that you have a disease
• direct contact is when a disease is transferred directly from one person to another
• direct contact examples:

  1. touch
  2. semen
  3. sweat
  4. saliva
• indirect contact is when disease is spread indirectly
• indirect contact examples:

  1. eating contaminated food
  2. drinking contaminated water
  3. touching the same surface as an infected person
• Theres four groups which pathogens belong to
• Four groups which pathogens belong to:

  1. virus
  2. bacteria
  3. protoctista
  4. fungi
• Viruses are not living organisms, they can only reproduce inside host cells.
• virus (viral disease) examples: influenza, common cold, polio, measles, AIDS
• bacteria (bacterium diseases) examples: cholera, syphilis, whooping cough, tuberculosis, tetanus
• protoctista (protist diseases) examples: malaria and amoebic dysentery
• fungi (fungal diseases) examples: athlete's foot and ringworm
• theres 5 body defences in our body
• examples of body defences:

  1. skin
  2. nose hair
  3. mucus
  4. stomach
  5. nose
• skin is a body defence that prevents bacteria from entering in the forms of dirt, sweat and oil.
• the nose hairs in our nose trap the pathogens and filter the air we breath
• the mucus in our airway traps pathogens and bacteria
• the stomach produces hydrochloric acid which kills any bacteria in food
• if our nose smells something bad like rotten or contaminated food, then it prevents us from eating it
• there are two types of white blood cells: phagocytes and lymphocytes
• an immune reaction is a reaction against pathogens
• lymphocytes produce antibodies to fight off specific diseases
• pathogens produce antigen
• a phagocyte kills the antigen-antibody complex
• lymphocytes produce antibodies which kill the antigens or trap them for the phagocytes to kill them
• antibodies are only produced when the body gets an alert that theres antigens in the body
• antibodies have a complementary shape that fit the antigens
• cholera is a serious bacterial disease that causes severe diarrhea
• cholera is spread by contaminated water or food
• the symptoms of cholera include dehydration, vomiting, and muscle cramps
• treatment for cholera includes rehydrating with fluids and electrolytes
• cholera bacteria reproduce and live in the small intestine
• cholera can be prevented through proper sanitation and hygiene practices
• cholera bacteria secrete a toxin that causes the intestine to secrete chloride ions