When Oxygen comes in contact with blood , clotting of blood takes place, hence flow of blood stops through the wound. If this is the case then why blood does not clot in lung when it comes in contact with Oxygen? P.J.LAKHAPATE plakhapate@rediffmail.com
Exposure to oxygen is not what activates clotting. The clotting cascade is activated by the rupture of endothelial cells (ie. blood vessels). This event is independant to whether or not any blood comes in contact with the outside air.
Herc: The intrinsic clotting pathway isn't activated by endothelial damage. Why wouldn't intrinsic clotting occur in the lungs? Is it because the extrinsic pathway must be activated first?
Having said that, I'm not entirely sure what "abnormal surfaces produced by injury" and "trauma" specifically refer to.
Well, maybe somewhat the right idea but the wrong page. That's a clot in the pulmonary artery that traveled from somewhere else in the body and is blocking the blood flow to the lungs. It not actually a clot in the lungs themselves. However, it can lead to severe coughing which can rupture capillaries and cause blood to enter the lungs BUT still no clots form in there.