Chapter 22, part 1

1. Chapter 22, part 1 The Lymphatic System and Immunity

2. Learning Objectives • Describe the structure and function of lymphatic cells, tissues and organs • List the body’s nonspecific defenses and describe the components and mechanisms of each • Define specific resistance and distinguish between cell-mediated immunity and antibody mediated immunity

3. Learning Objectives • Discuss the role of the T cell, B cell and antibodies in specific immunity • Describe the origin, development, activation and regulation of normal resistance to disease • Discuss the effects of stress and aging on the immune system

4. SECTION 22-1An Overview of the Lymphatic System and Immunity

5. lymphatic system • The lymphatic system • Contains cells, tissues, and organs responsible for defending the body • Lymphocytes resist infection and disease by responding to • Invading pathogens such as bacteria or viruses • Abnormal body cells such as cancer cells • Foreign proteins such as toxins

6. Figure 22.1 The Components of the Lymphatic System Figure 22.1

7. SECTION 22-2Organization of the Lymphatic System

8. The lymphatic system consists of • Lymph • Lymphatic vessels • Lymphoid tissues and organs • Lymphocytes and supporting phagocytic cells

9. Functions of lymphatic system • Primary function is production, maintenance, and distribution of lymphocytes • Lymphocytes must: • Detect where problems exist • Be able to reach the site of injury or infection

10. Lymphatic vessels include • Lymphatic capillaries • Small lymphatic vessels • Major lymph-collecting vessels

11. Figure 22.2 Lymphatic Capillaries Figure 22.2a, b

12. Figure 22.3 Lymphatic Vessels and Valves Figure 22.3a, b

13. Major lymph-collecting vessels • Superficial and deep lymphatics • Thoracic duct • Cisterna chyli • Right lymphatic duct

14. Figure 22.4 The Relationship between the Lymphatic Ducts and the Venous System Figure 22.4a

15. Figure 22.4 The Relationship between the Lymphatic Ducts and the Venous System Figure 22.4b

16. Figure 22.4 The Relationship between the Lymphatic Ducts and the Venous System Figure 22.4c

17. Lymphocytes • Three classes of lymphocytes • T (thymus dependent) cells • B (bone marrow-derived) cells • NK (natural killer) cells

18. Lymphocyte production (lymphopoiesis) • Involves bone marrow, thymus, and peripheral lymphoid tissue • B cells and NK cells mature in bone marrow • T cells mature in the thymus

19. Figure 22.5 The Derivation and Distribution of Lymphocytes Figure 22.5a-c

20. Lymphoid tissue • Connective tissue dominated by lymphocytes • Lymphoid nodules • Lymphocytes densely packed in areolar tissue • Found in the respiratory, digestive, and urinary tracts • MALT (mucosa-associated lymphoid tissue) • Collection of lymphoid tissues linked with the digestive system

21. Figure 22.6 Lymphoid Nodules Figure 22.6

22. Lymphoid organs • Lymph nodes – function in the purification of lymph • Afferent lymphatics – carry lymph to nodes • Efferent lymphatics – carry lymph from nodes • Deep cortex dominated by T cells • Outer cortex and medulla contains B cells

23. Figure 22.7 The Structure of a Lymph Node Figure 22.7