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Blood. Water compartments. 2 / 8. about 60% of our body is water (young-old, male-female) water is located in compartments, movement is regulated intracellular : extracellular 2:1, i.e. 40:20% interstitial : blood plasma 3:1, i.e. 15:5%
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Water compartments 2/8 • about 60% of our body is water (young-old, male-female) • water is located in compartments, movement is regulated • intracellular:extracellular 2:1, i.e. 40:20% • interstitial:blood plasma 3:1, i.e. 15:5% • barriers: cell membrane, endothelium – water diffuses easily through • measurement of the compartments by the dilution method: Evans blue, inulin, tritiated water • main regulator of the compartments: kidney • input-output through the extracellular compartment: drinking, urine, feces, breathing • balance very important: cholera, diarrhea, water poisoning, severe burns
Components of the blood 3/8 • main functionsof blood: transport (nutritients, wastes, signals, heat), protection • composition: cellular elements (44%) and plasma - hematocrit • plasma:90% water, diffusible ions (Na+, Cl-, HCO3-, H2PO4-) and small molecules (sugar, urea, etc.) and non-diffusible proteins • concentration of proteins (colloids) 6-8 g%, i.e. 200 g in total • protein fractions: • albumin (3,5-5 g%): oncotic (colloid osmotic) pressure • globulins (2-4 g%): antibodies, transport proteins • fibrinogen (0,2-0,4 g%): blood clotting – serum remains if removed • proteins and Hgb – buffer effect
Production of blood cells 4/8 • 3,7 x 1011cells each day from stem cells • with the exception of T lymphocytes, all cells are produced in the red bone marrow (1,5 kg) – yellow is inactive, mostly fat • stem cells are self-reproducing • during development they differentiate into progenitors that are not self-reproducing • after a given number of divisions mature cell • development and differentiation is controlled by cytokines, e.g. erythropoetin • erythropoetin is produced in the kidney (85%) and liver (15%) specifically stimulates red blood cells progenitors • it is regulated by O2level
Blood cell types 5/8 • red blood cells (erythrocyte) , • diameter 7-8 μ, thickness 2 μ, 5 million/microliter • hemoglobin content 14-15 g% (twice as much as plasma proteins – osmotic importance of compartmentalization) • remain within the vessels (except injuries), live for 120 days • have no nucleus when mature, but mRNS for Hgb is present, synthesis is continuing - reticulocyte • normally only in the bone marrow, increased number with intense production – diagnostic value • white blood cells (leukocytes):granulocytes, monocytes, lymphocytes: 5-6 thousand/microliter • granulocytes • 12-15 μ, multilobed nucleus, cytoplasmic granules - phagocytic function • neutrophils (50-70% of all, granules stained by neutral dyes), eosinophils (granules stained by acidic dyes), basophils (staining with basic dyes) • all are microphages, leave the blood stream within 7 hours, survive for a few days Berne and Levy, Mosby Year Book Inc, 1993, Plate 1.
Blood cell types II. 6/8 • monocytes • diameter 15-20μ • leaving the blood stream in 1-2 days they live for days or even years • macrophages • lymphocytes • diameter 6-20μ • they generate the immune response – can live for decades • 20-40 % of all white blood cells • B-cells (produced in the bursa of Fabricius (bursa Fabricii) in birds and in the bone marrow in mammals) become plasma cells and produce immunoglobulins (antibodies) • T-cells (produced in the thymus) – cellular immune response, e.g.transplantation • antigen – antibody reaction is followed by the activation of the complement factors (20 proteins)
Blood cell types III. 7/8 • lymphocytes continued • structure of the immunoglobulins – 4 peptid chains, variable regions • vaccination(passive and active) • blood types – AB0, Rh, incompatibility during pregnancy, paternity cases (DNA is more reliable – see O.J.Simpson), anthropology • autoimmunity (myasthenia gravis, lupus, etc.) • platelets • small fragments of magakaryocytes (60 μ) • stay in the blood stream, survive for 10 days • 150-300 thousands/microliter • role in the initiation of blood coagulation
Hemostasis 8/8 • high blood pressure – hemorrhage after injury • clotting or coagulation of blood prevents exsanguination • delicate balance – error: bleeding or thrombosis – thrombus vs embolus • external (tissue damage) and internal (glass test tube) pathways • prothrombin-thrombin transformation is the key • at least 16 important factors are needed - numbered or named after patients • Ca++is necessary for many steps – organic acids prevent clotting • most factors are produced in the liver – vitamine K is needed – rat killing with dicumarin • thrombin is a protease, activates factors and transforms fibrinogen into fibrin polymer
Blood preparation Berne and Levy, Mosby Year Book Inc, 1993, Plate 1.