Chapter 22, part 2

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

Fundamentals of

Anatomy & PhysiologySIXTH EDITION

Frederic H

. Martini

PowerPoint® Lecture Slide Presentation prepared by Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii

Chapter 22, part 2

The Lymphatic System and Immunity


• Located behind sternum in anterior mediastinum

• Capsule

• Two lobes

• Divided into lobules, each with a cortex and medulla

• Cortical lymphocytes surrounded by reticular endothelial cells

• Maintain blood–thymus barrier

• Secretes thymic hormones: thymosins, thymopoietins, and thymulin

The Thymus


Figure 22.8 The Thymus

Figure 22.8a-c


• Largest mass of lymphoid tissue

• Cellular components form pulp

• Red pulp contains RBC

• White pulp similar to lymphoid nodules

• Spleen functions include

• Removal of abnormal blood cells and other blood components

• Storage of iron

• Initiation of the specific immune response

The Spleen


Figure 22.9 The Spleen

Figure 22.9a-c


• Nonspecific defenses

• Do not distinguish one type of threat from another

• 7 types

• Specific defenses

• Protect against particular threats

• Depend upon the activation of lymphocytes

Lymphatic system and body defenses


SECTION 22-3 Nonspecific Defenses


• Keep hazardous organisms outside the body

• Includes hair, epithelia, secretions of integumentary and digestive systems

Nonspecific Defenses, Physical barriers

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 22.10

Figure 22.10 Nonspecific Defenses (Part 1 - Physical Barriers)


• Remove cellular debris and respond to invasion by foreign pathogens

• Monocyte-macrophage system - Fixed and free

• Microphages – Neutrophils and eosinophils

• Move by diapedesis

• Exhibit chemotaxis

Nonspecific Defenses, Phagocytes


Figure 22.10 Nonspecific Defenses(Part 2 - Phagocytes)

Figure 22.10


• Constant monitoring of normal tissue by NK cells

• NK cells

• Recognize cell surface markers on foreign cells

• Destroy cells with foreign antigens

Nonspecific Defenses, Immunological surveillance


NK cell activation

• Recognition of unusual surface proteins

• Rotation of the Golgi toward the target cell and production of perforins

• Release of perforins by exocytosis

• Interaction of perforins causing cell lysis


Figure 22.10 Nonspecific Defenses(Part 3 - Immunological Surveillance)


Figure 22.11 How Natural Killer Cells Kill Cellular Targets


Nonspecific Defenses, Interferons (cytokines)

• Small proteins released by virally infected cells

• Trigger the production of antiviral proteins

• Three major types of interferons are:

• Alpha– produced by leukocytes and attract/stimulate NK cells

• Beta– secreted by fibroblasts causing slow inflammation

• Gamma – secreted by T cells and NK cells stimulate macrophage activity


Figure 22.10 Nonspecific Defenses(Part 4 - Interferons)

Figure 22.10


Nonspecific Defenses, Complement system

• Cascade of ~11 plasma complement proteins (C)

• Destroy target cell membranes

• Stimulate inflammation

• Attract phagocytes

• Enhance phagocytosis


Complement proteins interact with on another via two pathways

• Classical

• Alternative


Figure 22.10 Nonspecific Defenses(Part 5 - Complement System)


Figure 22.12 Complement Activation

Figure 22.12


Nonspecific Defenses, Inflammation

• Localized tissue response to injury producing

• Swelling

• Redness

• Heat

• Pain

• Effects of inflammation include

• Temporary repair of injury

• Slowing the spread of pathogens

• Mobilization of local, regional, and systemic defenses


Figure 22.10 Nonspecific Defenses(Part 6 - Inflammatory Response)

Figure 22.10


Figure 22.13 Inflammation

Figure 22.13


Nonspecific Defenses, Fever

• Maintenance of a body temperature above 37.2oC (99oF)

• Pyrogens reset the hypothalamic thermostat and raise body temperature

• Pathogens, toxins, antigen-antibody complexes can act as pyrogens


Figure 22.10 Nonspecific Defenses(Part 7 - Fever)

Chapter 22, part 2

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