Lymphatic and Blood Tutorial 2024 PDF

Immunity: Lymphatic system and Blood tutorial 21 November 2024 1  Overview of session Welcome and Attendr Understand role of Lymphatic system in immunity Understand role of B and T lymphocytes in immunity Understand the underlying process of antige...

Immunity: Lymphatic system and Blood tutorial 21 November 2024 1  Overview of session Welcome and Attendr Understand role of Lymphatic system in immunity Understand role of B and T lymphocytes in immunity Understand the underlying process of antigen recognition and importance of blood group compatibility 21 November 2024 2  Immunity: Role of Lymphatic system Lymphatic system has its own circulatory pathways and capillaries that cover the whole body. Important role in lymphatic drainage, homeostasis and maintaining circulatory volume. Hydrostatic pressure drives movement of lymph into/out of lymphatic capillaries, but intrathoracic pressure and muscular contraction maintains movement throughout lymph vessels, ultimately returning fluid into the circulatory system returning to the heart. BUT also has key role in immune defenses! 21 November 2024 3  Lymphatic system and blood = immune system 21 November 2024 4  Primary Lymphatic organs The red bone marrow and thymus gland are considered to be primary lymphatic organs in the immune system. Stem cells in the bone marrow produce Leukocytes (white blood cells) which can be categorised as Lymphocytes (T + B) and Myelocytes (neutrophils and macrophages) Lymphocytes (T and B) and Macrophages are key components of the defence against infection and the body’s inflammatory response. Question: T and B lymphocytes are stored in lymph nodes ready to fight infection when needed, but where do B and T lymphocytes reach maturity? 21 November 2024 5  Secondary Lymphatic organs Comprised of organs made up of Lymphoid tissue. Act as a series of filters which monitor the content of extracellular fluid, and where lymphocytes are activated. Note: Lymph transports foreign bodies to lymph nodes. Lymphoid tissue is found in; Lymph nodes, tonsils, adenoids, spleen, Peyers patches (ileum) and appendix. Lymphoid tissue can also be found in respiratory and GI tracts. Lymph nodes and Lymphoid tissues store concentrated populations of Leukocytes (WBCs including lymphocytes and macrophages) until needed to fight infection. 21 November 2024 6  Activity 1 In your tutorial worksheet, choose one of the lymph activities; this could be the wordsearch OR the matching exercise where you match organ with function. (10 mins) 21 November 2024 7  Blood: Role of B and T lymphocytes in immunity Antigen recognition and importance of blood group compatibility 21 November 2024 8  B lymphocytes Unlike the barrier defences, the immune system is programmable and adaptable, evolving daily as it comes into contact with foreign molecules. The immune system is activated when a foreign substance enters the body and is recognized as being “non-self”; antibodies are produced in response. B Lymphocytes secrete antibodies (specialized attack proteins) into the blood stream. Some B Lymphocytes (memory cells) remember this reaction and linger in the body ready to react if exposed to the same foreign substance again. This response is known as humoral immunity. 21 November 2024 9  Role of B lymphocytes in immunity 21 November 2024 10  T Lymphocytes When stimulated by a “non-self” antigen, T Lymphocytes attack foreign substances directly (no antibodies are produced). Known as cellular immunity. T cells react only to the antigen presented to them by macrophages as marked for destruction. (antigen presenting cells) “Killer cells” attach to the specific antigen using a receptor on their cell membrane. T cells have a regulatory role in B cell immunity, either facilitating B cell activity (helper cells) or restraining them (suppressor cells). 11 21 November 2024  Antigens and Blood group compatibility We have discussed how the immune system, specifically T and B lymphocytes mount an immune response against invading pathogens. But, it is not just bacteria or an allergen that triggers an immune response. Antigens: are any proteins or combination molecules of protein and glucose/lipids which can trigger a response in the body. In immunity, the response is against a “non-self” antigen. Most red blood cells have antigens on the surface which denote what type of RBC it is. This is genetically determined and where we get our blood type from: A, B, O combinations. 21 November 2024 12  Blood group antigens https://www.youtube.com/watch?v=vOcKth8ZEO4 (3 mins) 21 November 2024 13  Blood group compatibility Knowing the patient blood type allows us to make sure they only receive blood which is compatible to them. The table on the left shows who the recipient can receive blood from (donor) The + denotes Rhesus antigen positive, The – denotes Rhesus negative. If Rh- comes into contact 21 November 2024 with Rh+ antibodies ++ 14  Activity 2 Using your compatibility chart, determine what blood each patient can receive; Susan is Type O-. Alan is Type AB+. Karen is Type A+. Ash is Type B-. Which of our patients can donate to anyone? 21 November 2024 15