1. Lines in Defense in the Body

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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