Clotting occurs when blood platelets adhere to the edges of a breached blood vessel and release chemicals that attract more platelets, resulting in a plug, as MedlinePlus explains. The plug stops external bleeding and allows clotting factors to stimulate the aggregation of fibrin fibers that eventually seals the breach internally.
Blood clotting is also known as coagulation, according to the American Society of Hematology. The process prevents excessive blood loss. Platelets work with specialized proteins contained in plasma, which is the liquid part of blood, to form the clots that stop further bleeding. Generally, the body naturally dissolves these clots once the process of healing is complete.
However, blood clots are not always beneficial, warns the American Society of Hematology. They sometimes form inside uninjured blood vessels and fail to dissolve, which is extremely dangerous, and such cases require professional medical help. Clots of this nature can cause venal blockage that eventually results in swelling and pain.
There are several problems that can arise when clots block blood vessels, as explained by the American Society of Hematology. These include deep vein thrombosis, a condition that results from blood clots forming inside major veins of the lower limbs or less frequently, the pelvis, arms and other parts of the body. In certain situations, clots dislodge from their point of origin and migrate to the lungs, blocking certain critical vessels and causing pulmonary embolism, which is a potentially life-threatening condition.