1.  BIOL 252 Lecture Notes Chapter 22 The Lymphatic System and Immunity Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

2. The purpose of this chapter is to: 1.Understand the lymphatic system structure and function 2.Compare and contrast the innate and adaptive immune systems 3.Compare and contrast cell-mediated and antibody-mediated immunity Introduction Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

3. The lymphatic system consists of several structures and organs that contain lymphatic tissue, bone marrow, and a fluid called lymph that flows within lymphatic vessels Lymphatic System Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

4. Components of the Lymphatic System Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

5. The lymphatic system functions to: 1.Drain interstitial fluid 2.Transport dietary fats 3.Carry out immune responses Functions of the Lymphatic System Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

6. Lymphatic vessels begin as lymphatic capillaries, which are closed on one end  Lymphatic capillaries are located between cells of many tissues  Lymphatic capillaries merge to form lymphatic vessels, which have thin walls and many valves  Lymph flow is slow to sluggish, however it is assisted by the same muscle and respiratory pumps assisting in venous return Lymphatic Vessels and Capillaries Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

7. Lymphatic Capillaries Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

8. Dynamics of Capillary Exchange 910

9. From the lymphatic vessels, lymph passes through lymph nodes and then into lymph trunks  Lymph trunks include the lumbar, intestinal, bronchomediastinal, subclavian, and jugular trunks Lymph trunks then merge to form either the thoracic duct or the right lymphatic duct Lymph Trunks and Ducts Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

10. Interstitial fluid  lymph capillaries  lymph vessels  lymph trunks  lymph ducts  subclavian veins Formation and Flow of Lymph Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

11. Fig. 19.03

12.  Greek: big eaters, are a type of white blood cell that engulfs and digests cellular debris, foreign substances, microbes, cancer cells, and anything else that does not have the types of proteins specific of healthy body cells on its surface in a process called phagocytosis. These large phagocytes are found in essentially all tissues, where they patrol for potential pathogens by amoeboid movement. Besides phagocytosis, they play a critical role in nonspecific defense (innate immunity) and also help initiate specific defense mechanisms (adaptive immunity) by recruiting other immune cells such as lymphocytes. For example, they are important as antigen presenters to T cells. Greekwhite blood cellmicrobesphagocytosisphagocytespathogensinnate immunityadaptive immunitylymphocytesantigen presentersT cells Macrophages Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

13. Plasma cells, also called plasma B cells, plasmocytes, plasmacytes, or effector B cells, are white blood cells that secrete large volumes of antibodies. They are transported by the blood plasma and the lymphatic system. Plasma cells Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

14. Primary lymphatic organs are organs where immune cells become immunocompetent  Red bone marrow  Thymus - T cells or T lymphocytes, mature.T cells  T cells are critical to the adaptive immune systemadaptive immune system Lymphatic Organs and Tissues Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

15. Thymus Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

16. Secondary lymphatic organs and tissues include:  Lymph nodes - Lymph nodes are major sites of B, T, and other immune cells. Lymph nodes are important for the proper functioning of the immune system, acting as filters for foreign particles and cancer cellsBTimmune cellscancer  Spleen – a number of functions including filter blood like lymph nodes, producing antibodies and removing worn out blood cells  Lymphatic nodules - are found scattered throughout the mucous membrane of the small intestinemucous membrane Lymphatic Organs and Tissues Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

17. Histology of Small Intestine

18. The body system that carries out immune responses is the lymphatic system Nonspecific Resistance (Innate Immunity)  Present at birth and includes defense mechanisms that provide general protection against invasion by a wide range of pathogens Specific Immunity (Adaptive Immunity)  Involves activation of specific lymphocytes that combat a particular pathogen or other foreign substance Disease Resistance Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

19.  Innate immunity refers to a wide variety of body responses that serve to protect us against invasion of a wide variety of pathogens and their toxins  We are born with this kind of immunity  Two lines of defense: 1.Skin and mucous membranes 2.Internal defenses Innate Immunity Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

20. Mechanical defenses  Skin, mucous membranes, tears, saliva, mucus, cilia, epiglottis, urine flow, defecating, vomiting Chemical defenses  Sebum, lysozyme, gastric juice, vaginal secretions Skin and Mucous Membranes Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

21.  Antimicrobial proteins  Phagocytes  Natural killer cells  Inflammation  Fever Internal Defenses Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

22. Phagocytosis Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

23. Inflammation Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

25. Non-Specific Disease Resistance Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Non-Specific Disease Resistance Interactions Animation: You must be connected to the Internet and in Slideshow Mode to run this animation.

26. Adaptive immunity is the ability of the body to defend itself against specific invading agents  Antigens are substances recognized as foreign that provoke immune responses Adaptive immunity has both specificity and memory and is divided into 2 types 1.Cell-mediated 2.Antibody-mediated Adaptive Immunity Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

27. For an immune response to occur, B cells and T cells must recognize that a foreign antigen is present.  B cells can recognize and bind to antigens in lymph, interstitial fluid, or blood plasma  T cells only recognize fragments of antigenic proteins that are processed and presented in a certain way (cell-mediated) Pathways of Antigen Processing Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

28. In cell-mediated immunity:  An antigen is recognized and bound  A small number of T cells proliferate and differentiate into a clone of effector cells  The antigen is eliminated Cell-Mediated Immunity Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

29. In antibody-mediated immunity:  An antigen is recognized and bound  Helper T cells costimulate the B cell so the B cell can proliferate and differentiate into a clone of effector cells that produce antibodies  The antigen is eliminated Antibody-Mediated Immunity Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

30. Disease Resistance Overview Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Introduction to Disease Resistance Interactions Animation: You must be connected to the Internet and in Slideshow Mode to run this animation.