Transcript Immunity
THE IMMUNE SYSTEM DISEASE Disease – any condition that prevents the body from working as it should As a result the body may fail to maintain homeostasis Disease may result from : Toxic substances Abnormal cells Poor nutrition Organ malfunction Inherited disorders (genetic) Risky personal behavior Pathogens Pathogens Pathogens are organisms that invade the body causing disease Microbes (microscopic organisms) that are pathogens include viruses, bacteria, fungi and other parasites IMMUNITY Immunity is the ability of the body to resist disease through the production of antibodies or specialized cells which inactivate the foreign substance (pathogen, cancer cells etc) First–Line Defense Non specific defenses: Physical Barriers: skin, mucus ,cilia Chemical Barriers: body secretions like sweat, tears, saliva and stomach acid If 1st Line Fails then……… Infection Occurs Second-Line Defenses Inflammatory Response - a nonspecific response to tissue damage from injury or infection Increased Blood flow- redness, swelling, warmth and pain Affected cells release chemicals which attract phagocytes Macrophages (WBC’s) destroy bacteria or pathogens by engulfing them If pathogen is an virus, then body produces interferon a protein that “interferes” with virus reproduction Phagocytes and Granulocytes Phagocytes are large white cells that can engulf and digest foreign invaders. They include monocytes, which circulate in the blood, and macrophages, which are found in tissues throughout the body, as well as neutrophils, cells that circulate in the blood but move into tissues where they are needed. Macrophages are versatile cells; they act as scavengers, they secrete a wide variety of powerful chemicals, and they play an essential role in activating T cells. Neutrophils are not only phagocytes but also granulocytes: they contain granules filled with potent chemicals. These chemicals, in addition to destroying microorganisms, play a key role in acute inflammatory reactions. Other types of granulocytes are eosinophils and basophils. Mast cells are granule-containing cells in tissue nd 2 If Line Fails then………. Immune System Takes Over Third Line Defenses Immune Response - a specific response that attacks the disease causing agent Body produces antibodies which are proteins that attack the invaders or mark them for destruction by white blood cells Immune system cont Most antibodies and WBC’s that attack pathogens break down after defending the body Some white blood cells will remain that “remember “ the pathogens and can quickly divide and fight off later invasions of the same microbe Antigen- any substance that can cause an immune response (usually a protein) Ex- microbes (bacteria, virus), transplants, transfusions, pathogen wastes (toxins), pollen etc. Antibodies- proteins in the blood that react with the pathogens and inactivate foreign substances Antibodies are produced for specific antigens (think lock and key!) TYPES OF IMMUNITY INBORN IMMUNUNITY- Baby is born with antibodies II- ACQUIRED IMMUNITY A- Passive Immunity- Person receives antibodies from an outside source - Antibodies work quickly and are temporary - Ex- Mother to baby, Tetanus Shot II- ACQUIRED IMMUNITY B- Active Immunity Person’s body produces antibodies to a particular disease by either: 1) getting disease and making antibodies in response Ex- Chicken pox 2) Or they receive a vaccine and body makes antibodies in response Ex- Polio vaccine, MMR Slower but are long lasting Vaccine A vaccine is made from a weakened or dead form of a pathogen It prevents you from getting the disease by causing the body to produce antibodies Malfunctions of Immune System Allergies- sensitivity to certain antigens which cause body to produce histamine, which cause symptoms of runny nose, itching, swelling, rashes etc Antihistamines- medication that reduces effects of histamine Malfunctions of Immune System Autoimmune Response- immune system does not recognize “self” antigens and attacks them as foreign Ex- Diabetes, Lupus, rheumatoid arthritis Malfunctions AIDS – a person’s immune system is weakened due to the HIV virus A person with AIDS may die from infections that a person with a healthy immune system would easily destroy https://account.pbs.org/oauth2/activateaccount/7986997/A9AA2A5944AA558F03B 720E6A2149E21