What is the process called when blood cells clump together to form a clot?

The process of blood cells clumping together to form a clot is known as coagulation. This is a complex biological process that involves a series of steps leading to the transformation of liquid blood into a semi-solid gel, which is critical for stopping bleeding and initiating healing after injury.

Coagulation is initiated when blood vessels are damaged, exposing collagen fibers that encourage platelets to adhere and aggregate at the injury site. This forms a temporary "platelet plug." Following this initial phase, a cascade of reactions involving various clotting factors occurs, ultimately leading to the conversion of fibrinogen, a soluble plasma protein, into fibrin strands that weave through the platelet plug, solidifying the clot and preventing further bleeding.

The other terms refer to different processes in the body. Hematopoiesis is the formation of blood cells within the bone marrow. Hemolysis refers to the breakdown of red blood cells and the release of hemoglobin. Clotting factor release, while a part of the coagulation process, does not describe the overall phenomenon of blood cell clumping and clot formation.