Immune organs and diseases related to it

Immune organs and diseases related to it

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  ORGANS OF IMMUNESYSTEM NAME - ISHIKA MOHITE GUIDED BY - DR. CHAITALI NIRATKER SEMESTER - V BATCH - 2021
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  Outline o Introduction ofimmune organs o Primary Lymphoid organs o Secondary Lymphoid organs o Interactions between immune organs o Disorders of immune organs
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  Introduction to ImmuneOrgans • Immune organs play a crucial role in the body's defense against pathogens. • These organs are responsible for the production, maturation, and activation of immune cells. • Immune system consists of two organs – Primary Lymphoid organs and Secondary Lymphoid organs. • The major immune organs include the bone marrow, thymus, lymph nodes, spleen, and tonsils.
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  PRIMARY LYMPHOID ORGANS •The primary lymphoid organs are those organs where T-Lymphocytes and B- Lymphocytes mature and acquire their antigen specific receptor. • Primary lymphoid organs consist of the following organs: 1 Thymus Gland. 2 Bone Marrow.
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  Thymus  Thymus isa primary lymphoid organ found in all vertebrates.  The thymus is responsible for the maturation of T lymphocytes.  T lymphocytes undergo selection and education in the thymus, ensuring their ability to recognize and respond to foreign antigens.
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  Thymus Education • Priorentering the thymus T-cell precursor is lack antigen receptors TCR, CD4 and CD8 molecules on their surface . • During passage through the cortex of the thymus they differentiate to T cell that express TCR, CD4+ and CD8+ (Positive selection) • In the medulla, these cells differentiate into express either CD4+ if contacts a cell bearing class II MHC proteins or CD8+ if contact a cells bearing class I MHC proteins (Negative selection) • Negative & Positive selections are two processes eliminate immature T cells lacking proper antigen receptor specificities. • When T cell express the CD4 receptor become helper T cell while those express the CD8 receptor become cytotoxic T cell.
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  Bone Marrow  Bonemarrow is the primary site for the production of blood cells, including immune cells.  B lymphocytes are formed (originate) within the Bone marrow.  It is a lymphocyte cell and derived its name from the site of maturation.  After maturation, when they leave bone marrow, they express antigen binding receptor known a B- cell receptor (BCR)  At this stage this B-cell is known as naive B-cell, means do not previously encountered with antigen, these B cells then migrate to secondary lymphatic organs, such as the spleen or lymph nodes, where they wait to encounter foreign antigen.  Binding of the antigen to BCR cause the B-cell to divide rapidly and produced two types of B-cell  (1) Memory B cell (2) Plasma cell or effector B-cell
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  SECONDARY LYMPHOID ORGANS The secondary lymphoid organs are specially evolved to be sites within the body where naïve immune cells have the maximum possibility of meeting and responding to antigen.  They consist of : I. Spleen. II. Lymph nodes. III. Mucosa- associated lymphoid tissue.
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  Spleen  The spleenis the largest lymphoid organ in the body.  It filters blood and removes old or damaged red blood cells.  The spleen also plays a crucial role in immune responses by trapping and destroying pathogens.  It is located on the left side of the body just above the kidney.  It is enclosed by a capsule and divided by trabecula into communicable compartments.  It is composed of white pulp, rich in lymphoid cells and Red pulp contains large quantities of erythrocytes, macrophage and some lymphocytes.  The spleen is also referred to as the graveyard of RBCs.  It plays the dual role of removing aged or injured red blood cells in the red pulp and producing antibodies in the white pulp
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  Lymph Nodes  Lymphnodes are small, bean-shaped structures distributed throughout the body  They filter lymph fluid, trapping foreign substances and activating immune responses.  The lymph nodes are composed of medulla and cortex which surrounded by a capsule of connective tissue.  The cortical region contains primary lymphoid follicles, after antigenic stimulation enlarge to form secondary follicles with germinal center rich with B cells.  The paracortical area contains T cells and dendritic cells. Antigen presenting occurs in this area that result in T cell activation  The medullary area is rich with plasma cells.  Lymph nodes have two primary functions:  Filter out potentially harmful particles from the lymph & act with immune surveillance provided by macrophages and lymphocytes.
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  MALT (Mucosa AssociatedLymphoid Tissue)  MALT is located within the lining of the major tracts (digestive, respiratory and urogenital) system have a combined surface area and the major sites of entry of most pathogens.  These vulnerable membrane surface are defended by a group of organized lymphoid tissues known collectively as mucosal associated lymphoid tissue (MALT).  Examples:  Gut-associated lymphoid tissue (GALT),  Bronchus-associated lymphoid tissue (BALT) • Conjunctiva-associated lymphoid tissue (CALT).  Skin -associated lymphoid tissue (SALT).
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  Interactions between ImmuneOrgans • Immune organs work together to coordinate immune responses. • For example, lymphocytes produced in the bone marrow and thymus migrate to lymph nodes for activation. • The lymphatic system facilitates the movement of immune cells between different organs.
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  Disorders of ImmuneOrgans • Disorders affecting immune organs can lead to immune deficiencies or autoimmune diseases. • Examples of immune deficiencies include severe combined immunodeficiency (SCID) and acquired immunodeficiency syndrome (AIDS). • Autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus, result from the immune system attacking healthy tissues.