Lines in Defense in the Body

First Line of Defense Barriers of the Body Skin Mucous Membranes Tears Saliva Stomach Acid If a pathogen gets through these barriers the immune system is activated

Second Line of Defense Innate Immunity: nonspecific immune system that has a general ability to recognize and fight infections, but cannot provide long-lasting immunity

Second Line of Defense - Inflammatory Response Complex innate immunity reaction Causes accumulation of immune cells, release of inflammatory chemicals, and the activation of the complement cascade

Second Line of Defense - Inflammatory Response Phagocytosis: cells consuming other cells Inflammation: redness, heat, pain, and swelling caused by blood rushing to the area Prevents the infection from spreading Mast cells release chemicals to attracts white blood cells to the site of the injury Fever: body temperature is raised to destroy the invading pathogens

Complement Cascade Occurs when plasma proteins that naturally circulate through the blood become activated Steps: Pathogens are marked for phagocytosis Chemotaxis: chemicals attract macrophages to the site of infection Cell Lysis: complement proteins destroy the pathogen’s cell membrane Antibodies cluster and bind pathogens together

Two Types of Inflammation: Local Inflammation: confined to a specific area of the body Symptoms include redness, heat, swelling, pain, loss of function Systemic Inflammation: occurs in many parts of the body Symptoms are all the above plus increased neutrophil production and fever

Inflammation and Complement Cascade Trigger.... Macrophages and Natural Killer Cells to be called to the site Macrophages destroy cells using phagocytosis Natural Killer Cells use chemicals to destroy infections Dendritic cells trigger adaptive immunity

Third Line of Defense Adaptive Immunity: specific immune system that is made up of specialized cells that eliminate pathogens or prevent their growth Improves the more you are exposed to the pathogen