1.2 - 1.3 the Circulatory System

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1.2 The Circulatory System

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FISH SINGLE CLOSED CIRCULATION

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Disadvantages of single circulation:A single heart has to pump blood through the gill capillary network & the body capillary networkThis reduces blood pressure producing a sluggish flow of blood

Tr.Rez@SB2014

Tr.Rez@SB2014

Tr.Rez@SB2014

1.3 The mechanism of blood clotting

WHY?

The necessity of blood clotting

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Damaged blood vessels, tissues or blood plateletsCalcium ions (Ca2t)Vitamin KThrombokinase (thromboplastin)Prothrombin (inactive)thrombin (active)Fibrinogen (soluble)Fibrin (insoluble)Fibrin mesh traps red blood cells which dry up to form a blood clot

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Impaired Blood Clotting MechanismImpaired blood clotting mechanism:Making the blood clotting impossible orCausing blood to clot blocking the flow of blood within the blood vessels

Deficient in calcium & vitamin KCalcium & vitamin K must be present in blood for the formation of blood clotsIf body does not have enough Ca & Vit K; take longer time to clotIf totally missing, person who suffers a cut could bleed to death

Haemophiliahave an impaired blood-clotting mechanismblood is unable to form a clot due to the deficiency in the blood proteins taking part in coagulationhaemophiliacs may bleed to death or die of internal injuryTr.Rez@SB2014

Thrombosisformation of a clot / thrombus inside a blood vesselblocking blood flowstops the tissues from receiving the normal blood flow & oxygenIf not treated quickly, can cause damage / death of tissues in that areaClot in coronary artery : heart attackClot in brain : stroke

Deep Vein Thrombosis

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Coronary thrombosis

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