When you cut or injure yourself, your body stops the bleeding by forming a blood clot.
Proteins and particles in your blood, called platelets, stick together to form the blood clot. Blood clots form when there is damage to the lining of a blood vessel, either an artery or a vein. The damage may be obvious, such as a laceration, or may occur on the microscopic level. As well, blood will begin to clot if it stops moving and becomes stagnant.
Excessive blood clotting can occur if the body's clotting process is altered or wrongly triggered. Blood clots can form in, or travel to, the arteries or veins in the brain, heart, kidneys, lungs, and limbs. The two major types of blood vessels are veins and arteries. Arteries carry blood from the heart to the body; veins carry blood back to the heart.
