1. Anatomy and Physiology, Sixth Edition
Rod R. Seeley Idaho State University
Trent D. Stephens Idaho State University
Philip Tate Phoenix College
Chapter 22
Lecture Outline*
*See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. Lymphatic System and Immunity
Chapter 22
Lymphatic System and Immunity

3. Lymphatic System Lymph Lymphatic vessels Lymphatic tissue
Lymphatic nodules
Lymph nodes
Tonsils
Spleen
Thymus

4. Functions of the Lymphatic System
Fluid balance
Excess interstitial fluid enters lymphatic capillaries and becomes lymph
Fat absorption
Absorption of fat and other substances from digestive tract
Defense
Microorganisms and other foreign substances are filtered from lymph by lymph nodes and from blood by spleen

5. Lymphatic Vessels Carry lymph away from tissues Lymphatic capillaries
More permeable than blood capillaries
Epithelium functions as series of one-way valves

6. Lymphatic Vessels Lymphatic capillaries join to form Lymphatic vessels
Have valves that ensure one-way flow
Lymph nodes: Distributed along vessels and filter lymph
Lymphatic trunks: Jugular, subclavian, bronchomediastinal, intestinal, lumbar
Lymphatic ducts: Right and thoracic which connect to large veins

7. Lymph Drainage Into Veins

8. Lymphatic Tissue and Nodules
Consists mainly of lymphocytes
Encapsulated or not
Lymphatic nodules
Numerous in loose connective tissue of digestive (Peyer’s patches), respiratory, urinary, reproductive systems

9. Tonsils
Large groups of lymphatic nodules in nasopharynx and oral cavity
Provide protection against bacteria and other harmful material
Groups
Palatine
Pharyngeal
Lingual

10. Lymph Nodes Organized in cortex and medulla
Substances removed by phagocytosis or stimulate lymphocytes or both
Only structures to filter lymph
Afferent and efferent vessels

11. Spleen Located in left superior side of abdomen
Can be ruptured in traumatic abdominal injuries resulting in bleeding, shock, death
Blood flows through at 3 different rates
Fast (most), slow, intermediate
Functions
Destroys defective RBCs
Detects and responds to foreign substances
Limited reservoir for blood

12. Spleen

13. Thymus Located in superior mediastinum Divisions: Cortex and medulla
Site of maturation of T cells

14. Immunity
Ability to resist damage from foreign substances as microorganisms and harmful chemicals
Categories
Innate or nonspecific resistance
Mechanical mechanisms: Prevent entry or remove microbes
Chemical mediators: Promote phagocytosis and inflammation
Cells: Involved in phagocytosis and production of chemicals
Adaptive or specific immunity
Specificity: Ability to recognize a particular substance
Memory: Ability to remember previous encounters with a particular substance and respond rapidly

15. Mechanical Mechanisms and Chemical Mediators
Complement
Group of 20 proteins
Circulate in blood in inactive form
Become activated in cascade form: Classical or alternative pathway
Interferons
Prevent viral replication
Mechanical Mechanisms
Skin, tears, saliva, mucous membranes, mucus

16. Complement Cascade

17. Innate Immunity: Cells
White blood cells
Most important cellular components of immune system
Methods
Chemotaxis
Phagocytosis
Neutrophils
Phagocytic and first cells to enter infected tissue
Macrophages
Monocytes that leave blood, enter tissues
Large phagocytic cells
Basophils and mast cells
Promote inflammation
Eosinophils
Reduce inflammation
Natural killer cells
Lyse tumor and virus-infected cells

18. Inflammatory Response

19. Inflammatory Response
Tissue injury regardless of type can cause inflammation
Response initiated by chemical mediators that produce vasodilation, chemotactic attraction, increased vascular permeability
Types
Local: Symptoms are redness, heat, swelling, pain, loss of function
Systemic: Symptoms are increase in neutrophil numbers, fever and shock

20. Adaptive Immunity
Involves the ability to recognize, respond to, and remember a particular substance
Stimulants
Antigens: Large molecules
Foreign: Not produced by body, introduced from outside
Self-antigens: Produced by body
Haptens: Small molecules and capable of combining
Types
Humoral or Antibody-mediated: B cells
Cell-mediated: T cells

21. Origin and Development of Lymphocytes
B and T cells
Originate in red bone marrow
Move to lymphatic tissue from processing sites and continually circulate
Clones are small groups of identical lymphocytes

22. Origin and Development of Lymphocytes
Positive selection
Ensures survival of lymphocytes that react against antigens
Negative selection
Eliminates lymphocytes that react against self-antigens
Primary lymphatic organs (red bone marrow, thymus)
Where lymphocytes mature into functional cells
Secondary lymphatic organs
Where lymphocytes produce an immune response

23. Antigenic Determinants
Specific regions of a given antigen recognized by a lymphocyte
Antigenic receptors
Surface of lymphocyte that combines with antigenic determinant

24. Major Histocompatability Complex (MHC)
Most lymphocyte activation involves glycoproteins of cell surfaces called MHC molecules
Class I molecules display antigens on surface of nucleated cells, resulting in destruction of cells
Class II molecules display antigens on surface of antigen-presenting cells, resulting in activation of immune cells

25. Antigen Processing

26. Costimulation

27. Proliferation of Helper T Cells

28. Proliferation of B Cells

29. Lymphocyte Inhibition
Tolerance: To prevent the immune system from responding to self-antigens
Provoked by
Deletion of self-reactive lymphocytes
Preventing activation of lymphocytes
Activation of suppressor T cells

30. Antibody-Mediated Immunity
Antibodies or Immunoglobulins (Ig)
Classes: IgG, IgM, IgA, IgE, IgD
Structure
Variable region: Part that combines with anitgenic determinant of antigen
Constant region: Responsible for activities

31. Actions of Antibodies

32. Antibody Production

33. Cell-Mediated Immunity
Antigen activates effector T cells and produces memory T cells
Cytotoxic T cells lyse virus-infected cells, tumor cells, and tissue transplants
Cytotoxic T cells produce cytokines, which promote phagocytosis and inflammation

34. Interactions and Responses of Innate and Adaptive Immunity

35. Acquired Immunity Active natural immunity Active artificial immunity
Results from natural exposure to an antigen
Active artificial immunity
Results from deliberate exposure to an antigen
Passive natural immunity
Results from transfer of antibodies from a mother to her fetus or baby
Passive artificial immunity
Results from transfer of antibodies (or cells) from an immune animal to a nonimmune one

36. Ways to Acquire Adaptive Immunity

37. Effects of Aging Little effect on lymphatic system
Decreased ability of helper T cells to proliferate in response to antigens
Decreased primary and secondary antibody responses
Decreased ability of cell-mediated immunity to resist intracellular pathogens

38. Immune System Problems
Hypersensitivity reactions
Autoimmune disease
Severe combined immunodeficiency disease (SCID)
Transplantation
Acute rejection
Chronic rejection