1. Chapter 36-2: Defense Against Infectious Disease

2. Innate Immunity (non-specific)
1st line of defense (physical and chemical barriers)
Skin
Sweat
Tears
Saliva
Membranes lining body passages
Mucus
Stomach acid
urine
Contain enzymes (lysozyme) that break down bacteria cell membranes and walls

3. 2nd line of defense Infection starts (inflammatory response)
Symptoms of inflammation
Swelling
Redness
Pain
Heat
Damaged cells (mast cells) and WBC (basophils) release histamines to increase blood flow to area of infection

4. Warmth attracts phagocytes (WBC that engulf particles)
Macrophages, Neutrophil, and Monocyte ingest bacteria that enter tissue
Pus
Mixture of phagocytes, dead cells, bacteria, and body fluids
Pathogen destroyed, inflammation goes down, wound heals

6. Viral Infections Phagocytes cannot destroy viruses Interferons
Viruses can multiply inside of a phagocyte
Interferons
Proteins made by cells that have been infected by the virus
Interferon goes into neighboring cells
Neighbor cells make antiviral proteins that prevent viruses from multiplying

8. Acquired Immunity (3rd line of defense)
Two types of immune responses:
Antibody immunity
Cellular immunity
Gradual build up of resistance
White blood cells develop the ability to recognize, attack, and destroy foreign substances (antigens)
WBC produce antibodies for each antigen that enters
Controlled by the lymphatic system

9. Lymphatic System Helps defend against disease
Maintains level of body fluids
Lymph nodes filter pathogens from tissue fluids
Also makes lymphocytes (WBC)
Located in the tonsils, spleen, and thymus (gland above the heart)

10. Antibody (humoral) Immunity
T lymphocytes (T cells)
Made in bone marrow
Helper T cell interacts with B cell to activate immune response
B lymphocytes (B cells)
Produced in bone marrow
Activated by T cell
Becomes a plasma cell and produces antibodies that are released into blood and tissue spaces
Memory B cells stay in the blood stream to respond to a second attack

11. Cellular Immunity Cytotoxic (killer) T cells transformed from T cells
Stored in spleen, tonsils, lymph nodes
Do not form antibodies
Travel to infection site
Release enzymes to pathogens
Antigens are lysed and die

13. Passive Immunity Active Immunity
Acquire antibodies from another host
Passed from mother to child
Can come from injections of antibodies from an animal or human already immune to antigen
Develops when body is directly exposed to antigens
Can be induced by vaccines
Dead, weakened or incomplete portions of antigens
Causes immune response