Topic 8 1 - Immunology 69a506c8fbc84f29b4987ac01266d1f1.pdf

🤒 Topic 8.1 - Immunology Compare the Innate Immune System VS Adaptive Immune System* Innate Immune System (First line of defence) Present from birth, Non-specific defence. Rapid response,...

🤒 Topic 8.1 - Immunology Compare the Innate Immune System VS Adaptive Immune System* Innate Immune System (First line of defence) Present from birth, Non-specific defence. Rapid response, No memory of previous exposures. Includes physical barriers, chemicals, and basic cellular components. Adaptive Immune System (Second line of defence) Develops over time, Highly specific defence. Slower response (days), memory. Involves B cells, T cells, and antibodies. Communicates with the innate system for a more specific response. Define Haematopoiesis Haematopoiesis: - Stem cells and precursor cells develop into protective cells. Topic 8.1 - Immunology 1  Originating in the bone marrow → travel through circulation, and mature throughout the body. What are the 5 types of stem cells Totipotent: Can generate all cell types needed for a new organism, like a zygote or fertilized egg. Pluripotent: Capable of producing nearly all cell types, in the three germ layers (e.g., endoderm, mesoderm, ectoderm). Multipotent: Able to produce cells within a closely related family, such as haematopoietic stem cells. Oligopotent: Limited to generating a few cell types within the same family, for example, lymphoid cells. Topic 8.1 - Immunology 2  Unipotent: Can produce only one specific cell type. Can self-renew without relying on a separate stem cell pool for replenishment, e.g., epidermal stem cells producing skin. 2 forms of bone marrow Red bone marrow: red cells, most white blood cells Yellow bone marrow: some white blood cells. (colour from a high fat content) Where is Red Bone Marrow found Red bone marrow is typically found at the end of bones (epiphysis) in adults. Topic 8.1 - Immunology 3  Where is Yellow Bone Marrow Found Yellow bone marrow is typically found in the canal of the long bones in adults. What are Eosinophil cells Eosinophils are particularly involved in fighting parasitic infections and modulating allergic responses What is The complement system Topic 8.1 - Immunology 4  - activation of inflammation; - opsonization (labelling) of pathogens and cells for clearance/destruction - direct killing of target cells/microbes by lysis. What are Myeloid Cells Many innate immune cells mature in the bone marrow or shortly after entering circulation. These maturing cells —> myeloid cells. Difference between monocytes + macrophages Monocytes are present in blood circulation. (m1 +m2) Macrophages are mainly found in tissues, being tissue residents. M1 and M2 Monocyte functions include M1 Monocytes - Fight against infections and foreign invaders M2 Monocytes - healing what are the 4 types of phagocytic cells Monocytes (in circulation) Macrophages (in tissues) Neutrophils (in circulation, enter tissues) Osteoclasts (phagocytose bone, not pathogens but part of the system). phagocytic cells consume invading pathogens. what substance attracts phagocytes towards site of infection/injury chemoattractant Difference between MHC 1 and MHC 2 MHC is crucial component for T cell maturation and function. MHC Class I (MHC I) is on all nucleated/infected cells MHC Class II (MHC II) is only on antigen-presenting cells (APCs) What are CD4 Proteins CD4 recognise antigens which are presented to them by APCs CD4 + MHC 2 Topic 8.1 - Immunology 5  What are CD8 cells CD8 recognise antigens which are on the surface of infected cells such as virally infected cells CD8 + MHC I Where does maturation of B cells occur lymph nodes Where do T and B cells exist while awaiting activation? In the lymphatic system (lymph vessels or lymphatic vessels) What happens after T cell activation by APCs? Topic 8.1 - Immunology 6  Th cells (CD4 + MHC 2) are activated, and they, in turn, activate B cells. B cells mature into plasma cells, which then enter the circulation. Structure of Waldeyer’s Ring Located in the upper airway, the Waldeyer’s ring consists of 4 tonsillar structures. lymphoid tissue and thus contains lymphocytes (T and B cells) What is the role of microfold (M cells) on tonsils? How do M cells facilitate interaction with immune cells? M cells take up antigens expressed by pathogens. M cells are 'U' shaped, with a pocket toward the basal end, allowing T cells, B cells, and Antigen-Presenting Cells (APCs) to enter. Below the M cells is a lymph node, which releases mature activated B cells (plasma cells) to the epithelium of the tonsil. What larger system are tonsils a part of? tonsils are part of the mucosa-associated lymphoid tissue (MALT). What are Peyer’s Patches in the Gut Topic 8.1 - Immunology 7  Lymphoid cells found in the epithelium of the gut. Part of the gut-associated lymphoid tissue (GALT) Behind the epithelium sits mesenteric lymph nodes which supply the gut with B cells. Functions of the Spleen Spleen Functions: blood filter, Recycles old red blood cells. Stores platelets and other white blood cells Facilitates opsonization (coating bacteria with antibodies) for bacterial clearance. Acute Inflammation vs Chronic Inflammation Topic 8.1 - Immunology 8  Acute Inflammation (Good): Occurs in response to injury or infection. Immune cells are brought to the site → Clear infection or damaged tissue. Inflammation resolves once threat is eliminated. Typically lasts up to 2 weeks. Chronic Inflammation (Bad): Lasting inflammation, not resolving. Immune cells persist at the site without leaving. Continual search —> Causes ongoing tissue damages Possible Causes: Autoantigens or inappropriate responses to antigens. persistent tissue damage and health issues. Topic 8.1 - Immunology 9