Lymphatic System PDF

School of Pharmacy Pharmacy 101 (PHR1001M) Lymphatic System Dr Taghread Hudaib Dr Lorna Lancaster Summary Lymphatic System Primary Lymphoid Organs Secondary Lymphoid Organs Tertiary Lymphoid organs Janeway Immunobiology, Murphy and Weaver, 9th Edition, Garla...

School of Pharmacy Pharmacy 101 (PHR1001M) Lymphatic System Dr Taghread Hudaib Dr Lorna Lancaster Summary Lymphatic System Primary Lymphoid Organs Secondary Lymphoid Organs Tertiary Lymphoid organs Janeway Immunobiology, Murphy and Weaver, 9th Edition, Garland Science, Chapter 1 and Chapter 8 Lymphatic System A network of vessels and nodes that conveys lymph It returns plasma-derived interstitial fluids to the bloodstream and plays an important role in the integration of the immune system Broken down into Primary, secondary and tertiary lymphoid organs Lymph is a clear-to-white fluid of white blood cells (mainly lymphocytes) that attack bacteria and foreign bodies in the blood What does the lymphatic system do? The lymphatic system defend the body against pathogens (bacteria, viruses and fungi). Develop the body immunity by making lymphocytes that produce antibodies liable for defending the body against disease. Remove the excess fluids from the body. Absorption and transport of fats to the blood stream. Production of immune cells (lymphocytes, and antibody producing cells). Short video: https://www.youtube.com/watch?v=cCPyWFK0IKs Primary Lymphoid Organs Where immune cells develop Stem cells require stem cell niches to self- renew and differentiation. Haematopoietic stem cells ((blood-forming cells) reside in the bone marrow during foetal gestation Bone marrow remains the main site for Haematopoiesis in adults. T-lymphocytes complete maturation in the Thymus (another Primary Lymphoid organ). https://www.ncbi.nlm.nih.gov/books/NBK279395/ Primary Lymphoid Organs Where immune cells develop Stem cells require stem cell niches to self-renew and differentiation. Haematopoietic stem cells ((blood-forming cells) reside in the bone marrow during foetal gestation Bone marrow remains the main site for Haematopoiesis in adults. T-lymphocytes complete maturation in the Thymus (another Primary Lymphoid organ). Bone Marrow Transplant A bone marrow transplant or a stem cell transplant, is a used method to treat certain types of cancer including leukaemia, lymphoma, neuroblastoma and myeloma. Stem cells can now be collected from the blood rather than being collected from the bone marrow and that’s why this treatment method is often called stem cell transplants. https://www.youtube.com/watch?v=iQ5j21qe 85Y (short video)  Thymus T-cell development not complete until selection in the Thymus T-cell pre-cursors travel from bone marrow to the Thymus via blood Pass through defined developmental stages in specific thymic micro- environments That is specialised environment for T- cells to generate unique antigen receptors Then selected on the basis of their reactivity to self MHC-peptide complexes (expressed on stromal cells) T-cells proliferate extensively in the *MHC is Major Histo-compatibility complex thymus but most die there Secondary Lymphoid Organs Where the immune response is initiated Distributed throughout the body Include lymph nodes, spleen, mucosa associated lymphoid tissue (MALT) Lymph nodes and spleen most organised tissues MALT found associated with linings of multiple organs Tonsils, Peyer’s patches, appendix, lymphoid follicles in mucous membranes All have anatomically distinct regions of T-cell and B-cell activity and all develop lymphoid follicles (development and selection of B-cells) Lymphatic Capillaries and Blood Spleen Organises the immune response against blood-borne pathogens Supplied with antigens by splenic artery Red pulp – red blood cells destroyed White pulp – peri-arteriolar lymphoid sheath (PALS) with T- cells and B-cells Marginal zone – trap for antigens https://www.123rf.com/photo_117794768_stock-vector-spleen-anatomy-3d-medical-vector-illustration.htm l Lymph Nodes Fully committed to regulating the immune response and the first organised structure to face antigens connected with blood and lymph vessels, packed with lymphocytes, macrophages and dendritic cells. Three distinct regions Cortex – contains lymphocytes (B), macrophages and follicular dendritic cells Follicle – microenvironment to support development of B-cells Para-cortex – T-lymphocytes and dendritic cells (migrated from tissue) Medulla – Lymphocyte exit  Mucosa-Associated Lymphoid Tissue (MALT) Organises response to antigen entering mucosal tissues T- and B- cell zones and lymphoid follicles found in mucosal membranes Tonsils, adenoids and Peyer’s patches are organised MALT Gut-associated lymphoid tissue (GALT) – barely organised cluster of lymphoid cells M-cells: specialized epithelial cells of the mucosa-associated lymphoid tissues that transport antigen across the epithelium  Tertiary Lymphoid Tissue Site of the infection Lymphocytes activated by antigen in the SLT (skin associated lym.tiss)can return to these organs (lung, liver) Generate defined microenvironments that organise returning lymphoid cells https://www.researchgate.net/publication/7229162_Lymphoid_organ_development_From_ontogeny_to_neogenesis/figures?lo=1 What is Inflammation? Symptoms of inflammation have been recognised for a long time medically by Roman encyclopaedist Celsus in the 1st century AD who suggested The four classic signs of inflammation: Dolor: pain Rubor: redness Calor: heat Turgor: swelling, tumour Blood vessels dilate, leading to local swelling and the accumulation of components of the immune system. Activation of Toll-like receptors (TLRs) in epithelia and activated macrophages contribute to inflammation: the macrophages also secrete cytokines including chemokines that attract neutrophils. What happens when your body is invaded by a foreign body? Macrophages recognize invaders, then engulf and destroy most of them and keep markers of these invaders so the other cells can recognise them as foreign bodies. Macrophages release inflammatory substances (cytokines) as they engulf the invader, the cytokines bind to receptors on other macrophage cells to inform other cells of the response to the invader. Macrophages can’t destroy all foreign invaders so they travel to the lymph nodes and bring information about the invaders to the lymphocytes (called T-cells and B-cells once activated). The T-cells then divide and help macrophages, they can recognize damaged invaders’ markers (antigens) then they bind to these markers and become activated. Once activated, the T-cells (also called killer or helper cells) begin to divide and their number increases enough to moves toward the inflammation site and damage the invaders that will then be engulfed by the macrophages. Then B-cells role starts depending on the type of germ, the B-cells shoot out antibodies called immunoglobulins, B-cells divide and increase in number in the lymph nodes before they move to the inflammation site Swollen lymph nodes is a result of activated B- and T-cells made to fight foreign bodies. https://www.youtube.com/watch?v=iVMIZy-Y3f8&ab_channel=IMGENEX%20short%20video *short video 6 min video: https://www.youtube.com/watch?v=Fbzb75HA9M8 Cytokines and Chemokines Cytokines: signalling molecules (large group of proteins, glycoproteins or peptides), secreted by immune system cells. They mediate /regulate haematopoiesis, inflammation and immunity. Chemokine: Small molecules control the migration of cells inside the body https://www.sciencedirect.com/topics/immunology-and- microbiology/gamma-chemokine Immune response forms immune response can be: TNF-α and chemokines Prostaglandins (PG) Leukotrienes – leukocytes Platelet activating factor C5a – complement components + promotion of inflammation Leukotrienes https://en.wikipedia.org/wiki/Leukotriene Prostaglandins and TNF Prostaglandins: a group of physiologically active lipids derived from arachidonic acid, found in almost every tissue in humans and animals, they have diverse hormone-like effects in animals TNF: Tumour Necrosis Factor http://www.bloodjournal.org/content/119/3/651?sso-checked=true Inflammatory Diseases Chronic inflammation – Example of an Inflammatory disease persistent inflammatory stimulus * Short video Can be caused by: https://www.youtube.com/watch?v=eYk 3GdBw-28&ab_channel=Osmosis Pathogen Tumours Autoimmunity Atherosclerosis Heart disease Obesity Anything that results in tissue damage  Acute phase response The acute phase response (reaction) is an intrinsic body defence occurs during acute illnesses. involves the increase or decrease of production of certain blood proteins (acute phase proteins) https://www.youtube.com/watch?v=PzunOgYHeyg&ab_channel=Scienc https://vdilab.com/page.php?id=67 eABC 7 min video The innate and adaptive immune systems The innate immune response is activated by chemical characterization of the antigen. Adaptive immunity describes the antigen-specific immune response. Immune cells designed to attack that specific antigen are produced by the adaptive immune system https://www.astro.org/Patient-Care-and-Research/Research/Professional- Development/Research-Primers/Innate-and-Adaptive-Immunity  Rheumatoid Arthritis Auto immune disease Chronic inflammation of the joints Can affect haematologic, cardiovascular, and respiratory systems https://www.mayoclinic.org/diseases-conditions/rheumatoid-arthritis/symptoms-causes/syc-20353648 Produce antibodies that react to the Fc region of IgG Therefore, IgM-IgG complexes deposited in joints These complexes activate the complement cascade – type III hypersensitivity reaction. https://www.sciencedirect.com/topics/medicine-and- dentistry/type-iii-hypersensitivity Summary Lymphatic System Lymphatic System Primary Lymphoid Organs Secondary Lymphoid Organs Tertiary Lymphoid Organs Inflammation and Inflammatory Disease References Janeway Immunobiology, Murphy and Weaver, 9th Edition, Garland Science, Chapter 1 and Chapter 8 https://www.medicalnewstoday.com/articles/303087.php Thank you