1. Chapter 21: The Immune System

2. Hans Buchner – German bacteriologist who in the 1880s proposed that anti-bacterial proteins existed in blood…. start of the modern understanding of immunity

5. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 21.1: Overview of innate and adaptive defenses, p. 789. Innate defenses Surface barriers Skin Mucous membranes Internal defenses Phagocytes Fever NK cells Antimicrobial proteins Inflammation Humoral immunity B cells Cellular immunity T cells Adaptive defenses (a) (b)

6. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 21.2: Phagocytosis, p. 791. Innate defensesInternal defenses Lysosome Microbe adheres to phagocyte. Phagocyte forms pseudopods that eventually engulf the particle. Phagocytic vesicle is fused with a lysosome. Microbe in fused vesicle is killed and digested by lysosomal enzymes within the phagolysosome, leaving a residual body. Indigestible and residual material is removed by exocytosis. Phagocytic vesicle containing antigen (phagosome). Residual body Acid hydrolase enzymes Phagolysosome (a) (b) 1 2 3 4 5

7. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 21.4: Phagocyte mobilization, p. 794. Endothelium Basement membrane Capillary wall Inflammatory chemicals diffusing from the inflamed site act as chemotactic agents Innate defensesInternal defenses Neutrophils enter blood from bone marrow Margination Diapedesis Positive chemotaxis 1 2 3 4

8. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 21.12: Types of acquired immunity, p. 806. ActivePassiveActivePassive Acquired immunity Naturally acquired Artificially acquired Infection; contact with pathogen Antibodies pass from mother to fetus via placenta; or to infant in her milk Vaccine; dead or attenuated pathogens Injection of immune serum (gamma globulin)

9. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 21.14: Mechanisms of antibody action, p. 809. Inactivates by AntigenAntibody Fixes and activates Enhances Leads to Phagocytosis Chemo- taxis Nucleus Histamine release InflammationCell lysis Agglutination (cell-bound antigens) Precipitation (soluble antigens) Neutralization (masks dangerous parts of bacterial exotoxins; viruses) Complement Antigen-antibody complex Adaptive defensesHumoral immunity

10. The Immune Response in the body occurs in two ways: Nonspecific Immunity Specific Immunity