Human Body systems

• Antibodies vs. Antigens

  Antibodies are proteins found on the surface of B and T cells that destroy invasive microbes.

  Antigens are proteins on the surface of pathogens that recognize "itself".
• T-cells kill infected body cells.
• B-cells produce antibodies to fight off invaders.
• The Inflammatory Response

  Occurs when a pathogen enters the skin through a cut or insect bite. Specialized mast cells then recognize the pathogen and produce histamine.

  These histamines give out a chemical signal which then attract large macrophages. These macrophages engulf the pathogens. Since there is a lot of cellular activity, the area gets hot and swollen.
• Interferons

  They are chemicals that have been produced by a cell that has been infected by a virus.

  These chemicals signal nearby healthy cells to make antiviral proteins.

  These proteins prevent viruses from spreading and infecting host cells and multiplying inside them.
• Allergic Response

  It is similar to an inflammatory response, but it's triggered by allergens instead.
• Mast Cells

  They produce histamines and recognize pathogens in the inflammatory response system.
• Non-Specific/General Response

  It includes the first and second line of defense They prevent infections by blocking entry, creating a hostile environment or blocking reproduction of pathogens.
• Specific/Targeted Response

  It includes the third line of response. They defend against specific pathogens involving antibodies and antigens.
• What happens when the T cells are activated?

  They do not latch on to the pathogen directly, but r5ecognize the macrophages and infected cells containing pathogens in which display antigens on their cell surface.

  Once activated, they send signals to summon cytotoxic, (killer) T cells to destroy the macrophage or infected cell.

  If the live long enough, they become memory T cells which help recognize the same pathogen in the future, activating a secondary response.
• What happens when the B cells are activated?

  Activated B cells make multiple clones, and some make antibodies that are released into the bloodstream to deactivate pathogens, these cells are known as plasma B cells.

  Some plasma B cells then turn into Memory B cells if they live long enough, which will then recognize the same pathogen in the future to then launch a secondary response.
• 2nd Line of Defense

  • Inflammatory response
  • mast cells
  • macrophages (large phagocytes)
  • Interferons
  • fever
• 3rd Line of Defense

  When the B or T cells have a uniquely shaped antibody that latch on to an antigen that match their antibody, which causes it to become activated to then go through a series of changes.
• 1st Line of Defense

  • skin (sweat and oils)
  • body fluids (mucus, tears, gastric juices, and lysozymes)
  • cells with cilia lining airways
• Pathogen

  any agent that can cause a disease
• Vaccines vs. Antibodies

  Vaccines are a preventative method taken before getting the disease. They kill viruses and is usually only taken once, having a permanent effect.

  Antibodies kill bacteria and usually only work during the time of having the disease. They are usually taken after getting infected.
• Passive immunity

  You can get passive immunity by being born with it or by receiving antibodies through injections that were produced by other animals or in labs.

  Natural: transfer of antibodies from mother to fetus/child

  Artificial: injection of serum that contain antibodies after an individual has had the disease.
• Active Immunity

  It is acquired by being exposed to pathogens and then immunity is developed because of the body's B and T cells that produce antibodies.

  Natural: produced by the host/ individual

  Artificial: immunization/vaccines