Haematology

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  • haematology
    • components of blood
      • plasma
        • plasma proteins - albunin- osmatic reg, fibrinogen (clotting) and globulins eg hemoglobin
        • plasma solutes = high in NA and cl
        • PH= 7.35-45
      • Erythrocytes
        • Functions-to transport O2 and CO2
        • have a bioconcave shape with no organelles
        • lifecycle
          • Breakdown - dead RBC are phagocytosed and broken down by proteases - Golbin + haem-haem broken down into billiverdin and iron, iron is recycled and transported by transferring-Biliverdin is in bile salts and is broken down and excrted
          • eyrthropoeitin = hormone that stimulates RBC production
      • leukocytes
        • enisophyils
          • 3% of cells with a short lifespan, have granules with help destroy paraytes and induce inflammation
        • basophiyls
          • granules containing histamine - inv in inflammation
        • neutrophils
          • phagocytosis
          • defense againgst viruses
        • mono and macrophages
          • phagocytosis
        • lymphocytes
          • b cells
          • T cells
          • NK cells
        • mast cells
          • Important role in allergic reactions and inflammation, involving the release of histamine from their secretory granules • Important in defence against parasites because they recruit other types of leukocytes • Involved in angiogenesis
      • platelets
        • • Also called thrombocytes • Promote blood clotting when blood vessels are damaged • Generated in bone marrow by budding off from megakaryocytes, each producing 5 – 10 ,000 platelets • Lifespan = ~5-9 days • Physical features: • No nucleus • 2-4mm diameter
    • Transfusions and reactions
      • to replace blood volume
        • plasma
        • RBCS
        • activated platlets
      • blood antigens
        • ABO grouping
          • single N-glycan
          • O = universal donor as has no antigens
          • Type A have B antibodies ect
          • reaction
            • Igm = small antibodies
            • antibody binds to multiple antigens causing the cells to agglutinate = life threatening blood clots
        • Rh system
          • D antigen - (+/-), very antigenic and have small IGg antibodies
          • antibodies can cross placenta and can cause issues for 2nd borns
        • Kell system
          • signel A.A sub, K or k antigen + have IGg antibodies
        • Kidd system
          • glycoprotein -10 crosses of membrane
          • a- and b- visa versa
          • casues delayed reactions
        • Duffy system
          • inv in marlaria sus- - = resistant
    • Lymph
      • transport of white blood cells - if recognition occurs in lymph = poliferation in nodes = sweeling
      • removes dead cells and removes interstitial fluid
      • opsinization
        • = opions binding to traget cell or pathogen
          • these are complementray to antibodies +facilitate thier binding
      • complement cascade
        • proteases
          • degrade pathogens / cells
            • chemotaxes
            • activation of luekocytes
            • agglutionation
            • inflammation
    • heamostasis
      • mechnisms by whcih clotting is activated and stopped
      • is sensitive, localised, stable and highly coordinated
      • steps
        • vascular spasm
          • reduces blood loss and activated as a pain response or by hormones
        • plug formation
          • platelet adhesion
            • Platelets are attracted to damaged blood vessel by collagen fibres of the connective tissue underlying the damaged endothelial cells
              • instrinsic
          • release reaction
            • adhesion casue a chnage inproperties = extensions
            • + release of granules containing; ADP, sertoin and throbroxane, fibrogin wvas
          • aggrenation
            • release of ADP = sticky platelets
        • clotting
          • Series of (proteolytic) reactions that culminates in formation of fibrin threads.
          • Clotting involves several substances known as coagulation factors. • These include calcium ions (Ca2+), several inactive enzymes
      • coagulation cascade
        • intrinsic = activated by internal stress + exposure of collagen fibres
        • extrinsic= external harm, TF exposed
        • Prothrombinase converts prothrombin into the enzyme thrombin. • Thrombin converts soluble fibrinogen into insoluble fibrin. Fibrin forms the threads of the clot.
        • Platelet activation ? adhesion & externalisation of phosphatidylserine, forming a platform for coagulation factor complexes to assemble • Localised thrombin generation ?
        • further platelet activation and formation of a polymerised fibrin mesh
        • coag factros at rest circulate in inactive forms
      • measuring abnormal coag
        • APTT blood) •  into citrate • Chelates calcium preventing clotting
        • Ca ect activates and measure time to form clot
        • PT (prothrombin time)
          • Coagulation initiated by addition of • Tissue Factor (thromboplastin) • Calcium • Time to formation of fibrin clot
        • anticoagulants
          • warafin
          • aspserin

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