Understanding the Mechanism of Blood Clotting

hey! it’s me again.ūüėÄ Form5 Biology Chapter 1 . Check this out!

NECESSITY FOR BLOOD CLOTTING

  • Prevent excessive blood loss from the body when there is a damage of the blood vessel.
  • Maintain the blood pressure.
  • Prevent the entry of microorganism and foreign particles into the body.
  • Promote wound healing
BLOOD CLOTTING MECHANISM
  • When you get cut, platelets exposed to air and become sticky then clump together to plug the wound.
  • Clotting factors are released by platelets and damage tissue called thrombokinase.
  • Thrombokinase in the presence of calcium ions, converts prothrombin into thrombin
  • The formation of prothrombin in the livers requires vitamin K
  • Thrombin converts soluble plasma protein, fibrinogen into insoluble fibrin fibres which form a meshwork of thread over the wound.
  • As the blood flows, erythrocytes and platelets are trapped in the fibrin fibres and a blood clot are form.
CONSEQUENCES OF AN IMPAIRED BLOOD CLOTTING MECHANISM

PROBLEMS RELATED TO BLOOD CLOTTING INCLUDE HAEMOPHILIA AND THROMBOSIS 
HAEMOPHILIA
  • Haemophilia is a heritance disease due to the lack of certain gene for the production of certain factors.
  • This is an impaired clotting mechanism which causes serious bleeding¬†particularly¬†in the joints
  • The afflicted person may die as the result of excessive bleeding from even minor cuts and bruises because blood clotting cannot take place.
THROMBOSIS
  • Sometimes a local blood clot(thrombus) is formed on the damaged rough inner wall of the artery.
  • This may cause blockage of the artery known as thrombosis.
  • Embolus formed when the thrombus dislodges and is carried away by blood circulation.
  • It may trapped in a small artery where it blocked the blood flow, this condition called embolism.
  • The blocked coronary artery cuts off the supply of oxygen and nutrients to the heart muscles, hence causes the heart attack.
here are the link about the blood clotting :¬†http://www.youtube.com/watch?v=–bZUeb83uU&feature=related
erythrocytes trapped by fibrin
stages in blood clotting

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