infection & response

• communicable diseases can be passed from one person to another by direct contact or indirect contact (eg. a common cold)
• non-communicable diseases cannot be spread from person to person, but can be passed down through families (eg. depression)
• 5 METHODS OF TRANSMISSION :

  • direct contact = eg. shaking hands
• 5 METHODS OF TRANSMISSION :

  • water = eg. dirty water can transmit diseases like cholera
• 5 METHODS OF TRANSMISSION :

  • air = eg. people infected with common colds sneeze and can spray thousands or virus particles to infect others
• 5 METHODS OF TRANSMISSION :

  • unhygienic food prep = eg. undercooked or reheated food can cause food poisoning
• 5 METHODS OF TRANSMISSION :

  • vector = eg. any organism that can spread a disease is called a vector
• a pathogen is a disease-causing microorganism
• tobacco mosaic virus is a virus in plants that causes:

  • discolouration of the leaves
  • which means less photosynthesis can occur
  • so less glucose is produced
  • therefore the plant will not grow
• an antigen is a specific protein on the surface of a pathogen which stimulates an immune response. this is what antibodies latch on to
• WHITE BLOOD CELLS:

  phagocytes = engluf and digest pathogens (phagocytosis)
• WHITE BLOOD CELLS :

  lymphocytes = create antibodies and make antitoxins
• a vaccine is a dead or inactive part of a pathogen ; injected ; to create antibodies and memory cells
• painkillers are chemicals that relieve the symptoms but do not kill the pathogens, as the symptoms are treated your immune system still needs to combat the pathogen
• antibiotics are substances that slow down or stop the growth of bacteria eg. penicillin, these can be only for bacterial diseases
• a drug is a chemical substance that affects how the body/ brain works and functions
• when creating a new drug, it needs to be :

  • effective - good at treating the disease
  • safe - no unwanted harmful effects
  • uptake and removal - the body absorbs tbe drug and clears
  • stable - can be stored for a long period of time
• a virus gets inside your healthy cells and reproduces until the cell bursts
• WAYS SPREAD OF DISEASE CAN BE PREVENTED :

  • sanitation
  • vaccination
  • cooked food
  • protected sex
• morphene is a painkiller made from poppy seeds
• aspirin is a painkiller made from willow bark
• some heart medicines used to treat heart conditions are made from foxgloves
• a placebo is a fake vaccine or medication
• 4 TYPES OF PATHOGEN :

  • protist
  • viral
  • fungal
  • bacterial
• a hybridoma is a cell that has been grown in a lab to produce a specific antibody
• both plants and animals can be affected by pathogens
• bacteria are about 1/100th of a body cell
• bacteria make you feel ill by producing toxins that damage your cells and tissues
• pathogens can be spread by:

  • water
  • air
  • direct contact
• measles is a viral disease spread by droplets from an infection, and create a skin rash and a fever - vaccine available
• rose black spot is a fungal disease that affects the leaves of plants, meaning less photosynthesis can happen, and is spread by water or wind, treated by fungicides
• malaria is caused by a protist and is spread by mosquitos, and causes repeating episodes of fever, people can be protected by mosquito nets and insecticides
• salmonella is a type of bacteria that causes food poisoning by eating food thats been contaminated with it, protected by poultry vaccinations to control the spread
• spread of disease can be reduced by:

  1. being hygienic
  2. destroying vectors
  3. isolating infected individuals
  4. vaccination
• the defence system:

  1. the skin- acts as a barrier to pathogens and secretes antimicrobial substances that kill pathogens
  2. hairs and mucus- trap particles that could contain pathogens
  3. trachea and bronchi- secrete mucus to trap pathogens
  4. stomach- produces hydrochloric acid which kills pathogens that make it far from the mouth
• phagocytosis: white blood cells engulf foreign cells and digest them
• immune system: if pathogens make it into your body, the immune system destroys them, white blood cells are the most important part of the immune system
• antibodies: when some types of white blood cells come across foreign antigens, they produce proteins called antibodies that lock onto invading cells so they can be found and destroyed by other white blood cells
• antitoxins: these counteract toxins produced by the invading bacteria
• vaccinations involve injecting small amounts of dead or inactive pathogens which carry antigens, causing the body to produce antibodies to attack them even though the pathogen is harmless