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Body Defenses. pp. 395-404. Two Types of Defense. Why do we need defense? Nonspecific defense system 1 st line of defense 2 nd line of defense Specific defense system (“ immune system ”) 3 rd line of defense. 1 st Line of Defense. Skin & mucous membranes Where? Physical barrier
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Body Defenses pp. 395-404
Two Types of Defense • Why do we need defense? • Nonspecific defense system • 1st line of defense • 2nd line of defense • Specific defense system (“immune system”) • 3rd line of defense
1st Line of Defense • Skin & mucous membranes • Where? • Physical barrier • Chemical barrier (secretions)
2nd Line of Defense • Involves cells & chemicals to fight any invaders • Phagocytes & macrophages • Natural killer (NK) cells • Inflammatory response • Antimicrobial chemicals • Fever
Response to tissue damage Four cardinal signs/symptoms Redness Heat Swelling Pain (5th?)limited joint movement Inflammatory Response
Inflammatory Response, Cont’d • Injured cells release histamine & kinins
3rd Line of Defense • It is antigen specific • It is systemic • It has “memory” • Two types of immunity: • Humoral (antibody-mediated) • Cellular (cell-mediated)
Cells of the Immune System • Lymphocytes– circulate through the body (WBCs) • Form in bone marrow • Mature (become immunocompetent)when able to respond to antigen • B lymphocytes – humoral (produce antibodies) • Mature in bone marrow • T lymphocytes – cellular • Mature in thymus gland