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Chapter 12 Immunity and Body Defenses
What is the difference between:Active and Passive Immunity?
What is Specific/Non-Specific Defenses?What is the Immune Response?
What is the Inflammatory Response?
Immune System
A “Functional System”• Not a traditional organ system• Fight Pathogens (harmful, disease-causing
microorganisms)• Uses molecules and immune cells
(lymphocytes and monocytes)• Protects from most bacteria and viruses• Protection for transplant organs/grafts
Immunity
• Using cell attack, or chemicals and antibody molecules to resist disease
• Resistance of an organism to diseases or any particular infection
• Involves both specific and non-specificcomponents
Non-Specific Body Defenses
Responds immediately to protect the body from all foreign substances
Provided by intact skin and mucous membranes, and cellular proteins
Don’t Forget!!!Surface Membrane Barriers:first line of defense for skin and body membranes
Skin and Mucous Membranes
—Secretions and Sebum are acidic to prevent bacterial growth
—Keartin provides resistance against invaders
—Mucus, Nasal Hairs and Cilia will trap debris—Gastric juice, Vaginal Acid Mantle, Tears and
Saliva Inhibit growth
Other Non-Specific Defenses
Cell and Chemical Defenders Provide defense against pathogens
Phagocytesengulf and destroy pathogens
Natural Killer Cellsdirect attack of virus or cancer cells
Antimicrobial Chemicals
Interferonsreleased by infected cells to mobilize immune system
Complement(plasma proteins) intensifies the inflammatory response
Urinecleanses the lower urinary tract
Fever
• High body temperatures inhibit bacterial growth
• Enahances body repair
• Fosters the inflammatory and Immune responses
Inflammatory ResponseTriggered when body tissues are injuredSigns and Symptoms:
Redness, Heat, Swelling and Pain
Inflammatory Responsea form of non-specific body defense
• --Disposes of dead cells and tissues• --Promotes tissue repairs• --Prevents spread of agent to adjacent tissues• --Affected area releases chemicals to attract phagocytes
Specific Body Defenses
Commonly called the immune systemDefends against a particular foreign substance
Antigenforeign substance to the body a substance capable of prompting
the immune response--Normally not part of our own body--The strongest antigens are in protein form
Immune Response
Immune Response is the immune system’s response to a threat:
Increases the Inflammatory responseProtects against a specific invaderPrimes the body for future attacksAntigens are foreign molecules recognized as invadersProvides Antibodies
Specific Defense Action
Antibodies—unique proteins that protect against future attack
Humoral ImmunityProvided by antibodies present in the body’s fluids
Cellular (Cell-Mediated) ImmunityLymphocytesdefend the body acting on targets
Cells of the Immune System
Lymphocytes and Macrophages:• B Lymphocytes and T Lymphocytes (Helpers!)• Phagocytic Macrophages fight invaders
B CellsProduce antibodies and oversee humoral immunity
T Cells Non-Antibody producing cells
B and T Cells
• B and T Cells generate from hemocytoblasts in red marrow
• T Cells originate from the Thymus Gland• T Cells continuously circulate through the body• B Cells develop immunocompetence
in the bone marrow
• Once mature—B and T Cells migrate to the Spleen and Lymph Nodes
Macrophages
• Distributed throughout lymphoid organs and connective tissues
Arise from monocutes in bone marrowEngulf foreign particles and present antigens to T cellsProduce Monokines—Proteins important
in the immune responseRemain fixed and antigens come to them
Active Immunity
Active Immunity—B Cells encounter antigens and produce antibodies against them
Naturally acquired during infectionsArtificially acquired (Vaccines)
Vaccines a preparation of killed microorganisms, living attenuated organisms, or living fully virulent organisms that is administered to produce or artificially increase immunity to a particular disease
Why Vaccinate?
Vaccine Benefits:not exposed to signs or symptoms of a
diseasestimulate antibody production