Cells & organs of immune system

with the heip of this ppt peoples can understand cells and organs of immune system

1. Archana Soni Assistant Professor Shri Shankaracharya Mahavidyalaya, Junwani Bhilai (C. G.) INDIA Cells and organs of immune system

2. CONTENTS 1 ] Introduction 2] History of immunology 3] Innate and adeptive immunology 4] Cells of the immune system a] B-Cell b]T-Cell c] Natural killer cells 5] Organ of immune system a] Primary limphoid organ b] Bone marrow c] Thymus d] S econdary lymphoid organ e] Lymph nodes f] Spleen g] P ayers patches h ] MALT,GALT.

3. Introduction Immunology deals with the study of immunity and immune systems of vertebrates . Immunity broadly involves the resistance shown, and protection offered by the host organism against the infectious diseases. The immune system consists of a complex network of cells and their interactions . It is specific ally designed to eliminate infectious organisms from the body . This is possible since the organism is capable of distinguishing the self from non-self ,and eliminate non-self.

4. History of immunology - Metchnikoff [1845-1916] Metchnikoff is the R ussian zoologist. He discovered the importance of cells in immunity and phagocytosis . -Emil Von Behring [1854-1917] the greatest support for humoral theory came from the studies of behring ,a German bacteriologist . In 1890 ,he showed that it was possible to provide an animal with passive immunity against tetanus or lockjaw by injecting into it the blood serum of another animal infected with tetanus. -Alexander fleming [1881-1955] Fleming a British bacteriologist received Nobel prize in 1945 for his dicovery of penicillin . He discovered the antibiotic lysozyme .

5. INNATE AND ACQUIRD IMMUNITY Innate immunity-All living organisms are naturally gifted with the resistance to certain infections from birth and this natural defence mechanism is known as innate immunity or native immunity or natural immunity . It is also known as non –specific immunity Acquired immunity- the restistance developed by man during his life is known as acquired immunity or adeptive immunity.

6. Cell of the immune system Two types of lymphocytes namely B-cell and T-cell are critical for the immune system. In addition, several accessory cells and effector cells also participate. A] B- lymphocytes - the site of development and maturation of B-Cell occurs in bursa fabricus in birds ,and bone marrow in mammals. During the course of immune response. B-cell mature into plasma cell and secrete antibodies [ immunoglobulins ]. B-Lymphocytes are inimately associated with humoral immunity. B] T-Lymphocytes- the mononuclear , nongranular leucocyte that matures in thymus and that brings about cell mediated immunity is called T Lymphocyte. The T lymphocytes are thymus dependent cell. They mature under the influence of thymus hormones. The Tlymphocytes have a large nucleus and a rim of cytoplasm. They are highly concentrated in the blood and spleen.

7. Types of t -cells Ts cell [T-Suppressor cells]- Ts cells are a sub population of t cells that suppress the activity of B cells and other T cells. They are the regulatory T cells . They inhibit antibody production by B cell . They suppress the functions of the T killer cells and T helper cells. T cytotoxic cells [ Tc ] or T Killer cells [ Tk ]- The T Killer cells are a sub population of T Lymphocytes that kill micro-organism or body’s own cells. They are also called cytotoxic cells. They are represented by Tc Or Tk. The T Killer cells are effector cells.

8. T Helper cells – T helper cells- T helper cells are a sub population of T lymphocytes that help B cells and other T cells in immune responses. They are the regulator cells. They help the B cells and T cells in multiple ways . T helper cells are a sub population of T lymphocytes that help B cells and other T cells in immune responses. They are the regulator cells . They help the B cells and T cells and in multiple ways. The T helper cells are represented by T Helper.

9. organs of immune system Primary lymphoid organ - primary lymphoid organs are the major site of lymphopoiesis *. The thymus , the Bursa of fabricius in birds and bone marrow in mammals are the primary lymphoid organs. Thymus- Thymus is a primary limphoia organ . In mammals , the thymus is a pharyngeal derivation arising from the epithelium of the 3 rd and 4 th pharyngeal pouches at about the 6 th week of gestation. Bone marrow- bone marrow is a primary lymphoid organ. It is a solt tissue within the cavities of bones . In marrow is divisible into two regions , namely 1) vascular and adipose region 2) Haemopoietic region

10. Secondary lymphoid organ – The secondary lymphyoid organs are c oncerned with immune reactions. In the secondary lymphoid organs the lymphocytes are made functional. Lymph nodes – Lymph nodes are secondary lymphoid organs. They are complex , cellular ,spherical or ovoid structures present along the lymphatic ducts. Spleen – Spleen is a secondary lymphoid organ . It is a solid, encapsuleted organ located in the upper part of the abdominal cavity behind the stomach and close to the diapharagm . Peyers patches- peyer’s patches are secondary lymphoid tissues. They are MALT. (mucosa associated lymphoid tissue) . They are collection of lymphoid nodules packed together to from oblong elevation of the mucous memberane of the small intestine.

11. MALT- MALT is the mucosa associated Lymphoid tissue . The muvosal layer of alimentary canal,respiratory and urinogenital tracts is provided with dispersed groups of lymphoid tissues known as MALT. GALT – tissues are usually without a capsuie ( uncapsulated ) . In human beings the peyer’s patches, the tonsils and appendix are good examplesof lymphoid tissues found in the mucosal layer of the alimentary canal . Hence these tissues are also referred to as GALT ( Gut associated lymphoid tissue).