Lymphatic - PDF

• The lymphatic system returns fluids that leaked from the vascular system back to the blood.
• The lymphatic system protects the body by removing foreign material from the lymph.
• The lymphatic system performs immune surveillance.
• Lymphatic tissues include diffuse/loose lymphatic tissue, dense lymphoid tissue, and nodular lymphoid tissue.
• Lymphoid nodules and germinal centers are types of lymphoid tissues.
• Lymphatic vessels are made up of three-layered wall: endothelial cells (simple squamous epithelium), smooth muscles, and collagen fibers with fibroblasts.
• Lymphatic capillaries, lymphatic trunks, lumbar, intestinal, bronchomediastinal, subclavian, and jugular are parts of the lymphatic system.
• The thoracic duct originates from the cisterna chyli and empties into the left subclavian vein at its junction with the left internal jugular vein.
• IgM, which makes up 7-10% of immunoglobulins, is the largest size and exists as a pentamer, cannot cross the placenta, and is the most potent activator of the complement system.
• Secondary immune response is a process where the body produces more antibodies in response to initial antibodies.
• Immunoglobulin (antibodies) are divided into five classes: IgG, IgA, IgM, IgE, and IgD.
• IgA, which makes up 15% of immunoglobulins, is a dimer and is the major class of immunoglobulins in secretions such as tears, saliva, colostrum, and mucus.
• IgD, which makes up less than 1% of immunoglobulins, exists only as a monomer and is the main antibody on the surface of lymphocytes of newborns.
• IgE, which makes up less than 1% of immunoglobulins, exists as a monomer, mediates allergic and parasitic reactions, and does not fix.
• IgG, which makes up 75% of immunoglobulins, are all monomers and cross the placenta weakly activating the complement system.
• The right lymphatic duct empties into the right subclavian vein at its junction with the right internal jugular vein.
• Components of the lymphatic system include lymphocytes (small, medium, large) and other cells, lymphoid tissues and organs, and lymphatic tissue types such as diffuse, dense, and nodular.
• Primary lymphoid organs include the thymus and bone marrow.
• Secondary lymphoid organs include lymph nodes, spleen, tonsil, MALT, and Peyer’s Patches.
• Functions of the lymphatic system include returning fluids that leaked from the vascular system back to the blood, protecting the body by removing foreign material from the lymph, and performing immune surveillance.
• Types of lymphatic tissues include diffuse/loose lymphatic tissue, dense lymphoid tissue, and nodular lymphoid tissue.
• Acquired immune response, also known as adaptive or specific immune response, is following certain infection, involves an antigen and antibody reaction, and includes B lymphocytes (humoral/antibody mediated immunity) and T lymphocytes (cell mediated immunity).
• Waldeyer’s ring is lymphoid tissue around the throat.
• Lingual tonsils are located along the surface of the postero-third of the tongue.
• Types of mature lymphocytes include T cells (helper, cytotoxic, suppressor), and B cells (involved in humoral immunity).
• Palatine tonsils are located in the nasopharynx.
• Primary immune response is the first immune response after an infection.
• Innate immunity, also known as non-specific immune response, is present at birth, does not become efficient upon the second exposure to the same organism, and includes skin, mucous membrane, phagocytes, natural killer cell, inflammatory response, interferon, complement, and fever.
• Nasopharyngeal tonsils, also called adenoids if hypertrophied, are located in the nasopharynx.
• Peyer’s Patches are part of MALT and are located in the wall of the ileum, forming aggregates of lymphoid follicles and containing M cells.
• Medulla has pale staining, a central area, and is less cellular.
• The morphology of the Medulla includes a capsule, subcapsular sinus, cortical sinus, lymphoid follicles, paracortex, medullary cord, and medullary sinus.
• Tonsils are partially encapsulated lymphoid aggregates containing lymphoid nodules and are interconnected with the diffuse subepithelial lymphoid tissue, forming Waldeyer’s ring.
• MALT contains a large and diffuse collection of dendritic cells, lymphocytes (mostly B cells) and CD4+ T cells, IgA-secreting plasma cells, and APCs.
• Immunity can be specific or non-specific, specific being very specific and tailored to the individual, and non-specific being present at birth and does not become efficient upon the second exposure to the same organism.
• Immunity is the defense of the body against disease causing agents like transplant, blood transfusion, autoimmune, allergies, AIDS.
• MALT (mucosa associated lymphoid tissue) is found in the digestive, respiratory, and GUT, and contains 70% of all the body’s immune cells.
• T lymphocytes are located in spaces of the network in the cortex of the thymus.
• The red pulp of the spleen consists of splenic cords, interconnected network of splenic venous sinuses, and lymph nodes.
• The spleen is the production site of antibodies and activated lymphocytes.