1. Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik – 422222, India

2. OC-SBT052-U01-01 Introduction Programmes and Courses  SEP – SBT052 – Unit 01

3. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.3 Credits  Academic Inputs by Arun Punaji More. M.Sc. (Microbiology) Experience: 11 Years arunmesh@hotmail.com

4. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.4 How to Use This Resource  Counselor at each study center should use this presentation to deliver lecture of 40-60 minutes during Face-To-Face counseling.  Discussion about students difficulties or tutorial with assignments should follow the lecture for about 40-60 minutes.  Handouts (with 6 slides on each A4 size page) of this presentation should be provided to each student.  Each student should discuss on the discussion forum all the terms which could not be understood. This will improve his writing skills and enhance knowledge level about topics, which shall be immensely useful for end exam.  Appear several times, for all the Self-Tests, available for this course.  Student can use handouts for last minutes preparation just before end exam.

5. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.5 Learning Objectives  After studying this module, you should be able to:  Discuss different organs of immune system and  Describe functions of different organs of immune system

6. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.6 Introduction  When you contract any infectious disease and you go to a physician, you are subjected to some clinical examination.  Physician tell you to lye down and press his hand at the right side of the end of last rib.  Then he examines you by pressing his hand at the right side in middle portion of your belly.  Then he makes you to open your mouth and see deep inside with help of his torch.  Do you know what the physician is looking for?  He is examining your liver, spleen and tonsils.  All these are organs of immune system.

7. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.7 Organs of Immune System-1  Skin and Epithelial Layer:  Form the first line of defense against pathogen.  They prevent the entry into the body.  They discourage the growth of pathogen on their surfaces.  Liver:  The complement proteins are produced in liver.  C –reactive proteins are also produced in liver.  Both complement proteins and c –reactive proteins play important role in clearing infections caused by pathogenic bacteria.

8. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.8 Organs of Immune System-2  Bone Marrow All types of immune cells and other types of blood cells are generated in bone marrow. Differentiation of different types of immune cells occur in bone marrow. Maturation of B lymphocytes occurs in bone marrow. Cytokines, IL-7 required for the maturation of different cells of immune system is produce by the stromal cells of bone marrow.

9. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.9 Organs of Immune System-3  Lymphatic System:- It comprises of lymph vessels and organs along with these lymph vessels. The lymphatic system is made of with following components: Thymus Peyer’s patches Bone marrow Spleen Lymph nodes The organs of lymphatic system are classified into : Primary lymphoid organs Secondary lymphoid organs

10. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.10 Primary and Secondary Lymphoid Organs FeaturesPrimary lymphoid organs Secondary lymphoid organs OriginEctoendodermal junction or endoderm Mesoderm Development timeIn early embryonic life In late fetal life. PersistenceInovulates after puberty Persist in adult life. Effect on removalLoss of lymphocytesAlmost no change. ExamplesThymus, Peyer’s patches, bursa Spleen, lymph nodes Response to AgUnresponsiveFully reactive

11. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.11 Primary Lymphoid Organs-1  Thymus Gland: Located behind the upper part of the sternum bone. Show histologically Two distinct part: cortex and medulla. Cortex consist of actively growing lymphocytes. Medulla mainly consist of epithelial cells. Main function of thymus is production of thymus lymphocytes which are also called as T-lymphocytes or T dependent lymphocytes or in short T cells. During the maturation of T Cells in Thymus, T cells acquire new surface antigens called as Thy antigens.

12. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.12 Primary Lymphoid Organs-2  Mucosa Associated Lymphoid Tissues (MALT): These are specialized aggregates of lymphoid tissues lining the internal surfaces of respiratory system, alimentary canal and genito-urinary tract These are specialized aggregates of lymphoid tissues lining the internal surfaces of respiratory system, alimentary canal and genito-urinary tract which are constantly exposed to pathogens.  Scattered lymphoid follicles:  Peyer’s patches: (Gut associated lymphoid tissues)  Associated with gut mucosa.  Contain both B and T cells.  Predominant Ig produces is IgA.

13. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.13 Secondary Lymphoid Organs-1  Spleen: It is the largest lymphoid organ. It is the principle organ involve in humoral immune response. Ag stimulated lymphocytes actively grow and produce Abs in the spleen; therefore spleen is also called as principle organ of lymphoid system involved in antibodies production. The main immunological function of spleen is to facilitate the interaction between various types of lymphocytes and blood borne Ags.

14. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.14 Organs of Immune System  Anatomical locations of organs of immune system is shown here.  Observe it carefully to identify.

15. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.15 Secondary Lymphoid Organs-2 Spleen: The interaction of blood borne Ags and lymphocytes in spleen initiate humoral immune response. Beside immunological function, spleen also serve as major organ of filtration of abnormal lymphocytes and erythrocytes.

16. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.16 Secondary Lymphoid Organs-3 Lymph Nodes: It is the connective tissues bags filled with mobile immune cells. They are located around the lymphatic vessels at important anatomical sites. Lymph nodes show two main functional compartments : cortex and medulla. The enlargement of lymph nodes upon antigenic stimulation help in the clinical diagnosis of number of infectious diseases to physicians. Lymph nodes act as a filter for lymph draining from various anatomical sites.

17. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.17 Structure of Lymph Node

18. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.18 Secondary Lymphoid Organs-4 Lymph Nodes: The outer cortex region consist of smaller primary and secondary lymphoid follicles. They are packed with actively proliferating lymphocytes and dendritic cells. The secondary follicles are called as germinal centers for lymphocytes. On antigenic stimulation germinal center developed and enlarges due increasing population of lymphocytes. This results in the overall enlargement of lymph nodes.

19. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.19 What You Learn…  You have learnt :  Different organs of immune system such as  Bone marrow  Spleen  Liver  Thymus gland  Lymph nodes  Anatomical sites of organs of immune system  Basic anatomical structure of these organs.  Basic immunological functions of these organs.

20. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.20 Critical Thinking Questions  Why spleen is called as organ of antibody synthesis?

21. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.21 Tips for Critical Thinking Questions  Dense populations of B cells, interaction of different cells in spleen.

22. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.22 Study Tips  Book Title:Roitt’s Essential Immunology, 10 th ed. Title:Roitt’s Essential Immunology, 10 th ed. Author: Roitt I.M. Publication: Publication: Blackwell Science 2001.  Journal Article Title:An Overview Of The Immune System. Title: An Overview Of The Immune System. Author:Parkin J, Cohen B. Author: Parkin J, Cohen B. Publication: Publication: Lancet 2001; 357:1777-1789.

23. End of the Presentation Thank You !