The Immune System

1. The Immune System Jessica cochran, hollie braun, noah kosnick Mr. yotsuda Life science 8, period 7 The immune system is your body’s protection system, designed to defend your body from millions of bacteria, microbes, toxins, viruses, and parasites. The major components of the immune system are the thymus, lymph system, hormones, antibodies, spleen, bone marrow, white blood cells, and complement system.

2. Describing Organs: The Lymphoid Organs Antibodies: Protein cells that tag antigens for destruction Appendix: a small tube connected to large intestine Cilia: Sweep mucus upward and out of the system Epidermis: Skin’s outer layer of protection Lymph Nodes: small, bean-shaped organs located throughout the body connected via the lymphatic vessels Lymphatic Vessels: grid of channels throughout body that carries lymphocytes to the lymphoid organs and bloodstream) Mucus: Prevents particles and germs from entering the body; trap Saliva: Controls micro-organism growth in the mouth Spleen: fist-sized organ in abdominal cavity Thymus: two lobes joined in front of the trachea behind breast bone Tonsils: two oval masses in back of the throat White Blood Cells: defends the body against both infectious disease and foreign materials

3. Recognizing “Self” and “Nonself” The immune system distinguishes between “self” (cells and proteins belonging in the body) and “nonself” (foreign organisms and bacteria). If the immune system does not recognize “self”, it may attack itself. The immune response happens when a “nonself” invader is recognized for future “reference”, attacking more rapidly each time it reappears. Specific immune defenses are triggered by antigens, foreign substances that stimulate immune response. Antibodies (protein cells) mark these antigens for destruction. B lymphocytes and T lymphocytes are both produced in bone marrow and help remove antigens.

4. Humoral Immunity Humoral Immunity refers to the immune response that happens in body fluids. The process starts when Antigens, any foreign immune response trigger, binds to antibodies, cells that tag to antigens for deconstruction, and Helper cells (T cells) activate the B cells (antibodies). The activated B cells divide rapidly and produce plasma cells and memory B cells. The plasma cells create more antibodies to capture more antigens for deconstruction and die off once the infection is eradicated. Memory B cells remain alive so if the infection comes again it can quickly react to kill the virus.

5. Acquired Immunity Vaccinations: The injection of a weakened or less dangerous pathogen to produce immunity for the stronger version. (ex. Chickenpox, Polio, Tetanus) Active immunity: When a vaccination or open exposure (fighting an infection) stimulates the immune system with an antigen, producing memory B and T cells that quicken immune response. Passive immunity: Antibodies produced against a pathogen introduced into a person’s blood. This lasts only a short time, as the immune system eventually destroys the foreign antibodies.

6. FunFacts Your immune system may suffer from getting under 5 hours of sleep a night Autoimmune diseases (attacks “self”) mostly occur in women Bacteria outnumber our own cells 10 to 1 Only 1% per every 5 liters of an adult’s blood is white blood cells People who have less humor in their lives tend to have less protective immune responses Dieting can weaken the immune system People with less stress in their lives have a stronger immune system Eating fruits and vegetables is great for immunity Covering your mouth when you cough can prevent sickness from spreading Fevers release white blood cells, increase metabolism, and stop “nonself” organisms from multiplying