Image SS2385580 (Blood Clot, SEM)Colored scanning electron micrograph (SEM) of a human blood cl

Image SS2385580 (Blood Clot, SEM)

Colored scanning electron micrograph (SEM) of a human blood clot.

Here it has formed inside a blood vessel following an injury. Red blood cells (a.k.a. erythrocytes) are seen trapped by a web of brown fibrin threads. The fibrin is an insoluble protein and these threads are an essential mechanism for the arrest of bleeding.

Platelets (a.k.a. thrombocytes) are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby initiating a blood clot.

Learn More About Platelets

As the blood cells become trapped they lose their normal rounded shape (as at upper left). Blood clots form to repair blood vessels damaged by injury or disease.

Abnormal clotting in intact arteries and veins (as occurs in a thrombus) is the principal cause of heart attack and stroke.

On the other side of the coin, there is a bleeding disorder called, Hemophilia, where the blood does not clot properly. This can lead to spontaneous bleeding as well as bleeding following injuries or surgery.

Magnification: x2500 at 6x6cm size.