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21 Cards in this Set
- Front
- Back
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3 general functions of blood |
transport, immune response, coagulation |
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composition of plasma |
mainly water (90%), solutes (10%) |
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3 main plasma proteins and their function |
albumins - maintain osmotic pressure, buffer blood, bind and transport insoluble substances globulins - antibodies fibrinogen - precursor of fibrin during blood coagulation |
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what is the haematocrit? |
also known as packed cell volume, fraction of blood occupied by the RBCs |
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Shape of RBC |
biconcave disk - allows flexibility to distort and move through narrow capillaries, aswell as efficient diffusion of gasses through SA |
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how much Hb is in RBCs |
1/3 of weight of RBC |
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breakdown products of a RBC |
amino acids, iron and bilirubin |
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normal haemoglobin conc in blood |
~150 g/L |
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causes of Anaemia |
decreased production - low iron, low EPO, or malnutrition (dont have cofactors vit B12, folic acid) increased destruction - sickle cell, drugs |
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4 cofactors required for RBC production |
folic acid, vit B12, thymine, iron |
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process of formation of platelets |
thrombopoiesis |
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stage one of haemostatic response |
constriction of blood vessels to area, formation of platelet plug (platelets agglutinate, adhere and aggregate) |
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stimulus for stage one of haemostasis |
ruptured endothelial surface of blood vessel (collagen exposed) |
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activation of stage two and three coagulation phases |
prothrombin activation: requires both intrinsic and extrinsic factors intrinsic - everything necessary for this is in the blood extrinsic - a cellular element outside blood is required (eg. tissue factor from damaged tissue) |
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activation of factor x requires |
Ca 2+ |
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what is haemophilia? |
inability to form fibrin clot, through missing sequence of the pathway |
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5 factors which oppose clot formation? |
endothelial surface is smooth (prostacyclin inhibits aggregation, nitric oxide inhibits aggregation and vasodilates) tissue factor pathway inhibitor (inhibits extrinsic pathway) thrombin is inhibited via antithrombins warfarin- retard clotting (impairs vit K) aspirin - inhibits platelet aggregation |
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mechanism which causes dissolution of clot |
fibrinolysis |
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factor which differs between blood groups |
membrane proteins (antigen) |
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Rhesus positive blood have what antigen? |
D antigen |
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why isnt ABO system an issue with preganacy |
antibodies are of IgM type (do not readily cross the placenta) anti Rh are IgG type which can |
