Lymphatics and Immunity PDF

Lymphatics and immunity Dr Greg Davis Martini Chapter 22 Copyright notice  Learning objectives and reading At the end of this lecture you should be able to: o Name two major structures of the lymphatic system. o Describe the relationship between the lymphatic sys...

Lymphatics and immunity Dr Greg Davis Martini Chapter 22 Copyright notice  Learning objectives and reading At the end of this lecture you should be able to: o Name two major structures of the lymphatic system. o Describe the relationship between the lymphatic system and the circulatory system. o Define and identify both innate and adaptive immune systems, and describe the relationship between the immune system and the lymphatic system. o Define the following terms and place them within either the innate or adaptive immune system: Phagocyte, inflammatory response, complement, antigen, antibody, T-Cell, B-Cell. o Describe the mechanism of action of anti-bodies in preventing and fighting infection.  Lymphatic system Lymph (fluid) Lymphatic vessels Lymphoid tissues and organs – Primary where lymphocytes are formed Red bone marrow – Secondary Where lymphocytes are activated Lymph nodes, spleen  Functions Produce, maintain and distribute lymphocytes Protect against infections, foreign substances – Need to detect problems – Need to reach the site of injury or infection – Lymphocytes circulate in bloodstream – Enter or leave the capillaries Fluid is returned to bloodstream via lymph vessels Lymphatic components Lymphatic capillaries Comparison of vessels  Cells and tissues Cells called lymphocytes Comprise around 20-40% of circulating leukocytes – T cells (thymus dependent) – B cells (bone marrow derived) – NK cells (natural killer) Lymphoid tissue – loose connective tissue dominated by lymphocytes Lymphoid tissue Lymph node Lymph node  Thymus Has outer cortex – Packed with lymphocytes Inner medulla Function – Actively dividing T cell lymphocytes – Hormones to control T cells Thymus  Spleen Largest collection of lymph tissue – Removes abnormal blood cells – Storing iron from recycled red blood cells – Initiating immune responses using B and T cells Soft organ – sits in contact with left kidney, diaphragm and stomach – Red pulp: large quantities of rbcs – White pulp: lymphoid tissue – Vulnerable to rupture  Immunity Body response to infectious and abnormal agents Immune response – Innate or non-specific Barriers (skin) Phagocytes to attack bacteria NK cells important – Adaptive or specific T and B cell attack particular bacterium Provided by exposure or vaccination Production of lymphocytes Production of lymphocytes Adaptive defences Innate defences Innate defences Lymphocyte classes Types of immunity Overall defences Integrated summary  Summary Name two major structures of the lymphatic system. Describe the relationship between the lymphatic system and the circulatory system. Define and identify both innate and adaptive immune systems, and describe the relationship between the immune system and the lymphatic system. Define the following terms and place them within either the innate or adaptive immune system: Phagocyte, inflammatory response, complement, antigen, antibody, T-Cell, B-Cell. Describe the mechanism of action of anti-bodies in preventing and fighting infection.