Blood. Water compartments

Transcription

1 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% 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 1

2 Components of the blood 3/8 main functions of blood: transport (nutritients, wastes, signals, heat), protection composition: cellular elements (44%) and plasma - hematocrit plasma: 90% water, diffusible ions (Na +, Cl -, HCO 3-, H 2 PO 4- ) 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 cells 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 O 2 level 2

3 Blood cell types 5/8 red blood cells (erythrocyte), diameter 7-8 µ, thickness 2 µ, 5 million/microliter hemoglobin content 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 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 Blood cell types II. 6/8 monocytes diameter µ leaving the blood stream in 1-2 days they live for days or even years macrophages lymphocytes diameter 6-20 µ they generate the immune response can live for decades % 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) 3

4 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 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 4

5 Blood preparation Berne and Levy, Mosby Year Book Inc, 1993, Plate 1. Blood cells 5