The Immune System

Sheila L. Jett, NBCTMontevallo Middle School

The Immune SystemBell ringerWhat are some functions of your skin?Keeping Pathogens OutYou cant escape pathogens; they are everywhere! Pathogens are in the air you breathe, the water you drink, and on every surface that you touch. There is nothing to be afraid of because your body protects you most of the time. Your body has 5 major barriers to block pathogens.TearsSalivaSkinMucous membranesStomach acidImmune SystemIf pathogens get past the 5 barriers, then your immune system goes to work.Immune system is a combination of body defenses made up of cells, tissues, and organs that fight pathogens.One mechanism that your body uses to help keep pathogens from multiplying is to increase the temperature of your body. The lymphatic system is a secondary circulatory system that helps the body fight pathogens and maintains its fluid balance.Macrophages surround and destroy foreign substances and then help the lymphocytes identify the substance.Lymphocytes are special white blood cells in the body that fight pathogens.LymphocytesThere are 3 main kinds of lymphocytes B cells form in the bone marrow and produce antibodies to fight pathogens.T cells form in the thymus gland and kill pathogens.NK cells stands for natural killer because the attack cancers and viruses.Keeping your immune system healthyGet regular exerciseEat plenty of vitamin rich foodManage stressGet plenty of restAntigens and antibodiesLymphocytes are activated when the body recognizes the part of the pathogen called the antigen.Antigens are substances that send the immune system into action.Antibodies are specific proteins that attach to antigens, keeping them from harming the body.Response to infectionPathogens get past the barriers and antigens trigger the immune system.Macrophages engulf the pathogens and present to the t cells. The t cells identify the pathogens.T cells divide and multiply and signal the b cells to respond.The b cells divide and multiply.Some of the b and t cells become memory cells and do not respond to the first invasion.The b cells that do respond then release antibodies. They tag the pathogens for destruction by the t cells.Memory cells respond quickly if the same pathogen enters againVaccinations and ImmunityThe CDC recommends that teens be given four vaccinations chicken pox, hepatitis B, measles-mumps-rubella, and tetanus-diptheria. Vaccine preparation of dead or weakened pathogens that is introduced into the body to cause an immune response. (immunization)Immunity is the ability to resist the pathogens that cause a particular disease. Healthy mothers pass immunity to their babies during pregnancy and through breastfeeding after birth.