Science, Tech, Math › Science Coagulation Definition (Chemistry and Biology) Share Flipboard Email Print BirgitKorber / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated February 04, 2019 Coagulation is a gelling or clumping of particles, typically in a colloid. The term typically applies to the thickening of a liquid or sol, usually when protein molecules cross-link. When coagulation or clotting occurs in blood, it proceeds immediately after blood vessel damage. Two processes occur. Platelets change and the subendothelial tissue factor is exposed to plasma Factor VII, which ultimately forms fibrin. Primary hemostasis occurs when platelets plug the injury. Secondary hemostasis occurs as clotting factors strengthen the platelet plug with fibrin factors. Also Known As: coagulate, coagulating, clotting Examples of Coagulation Milk proteins coagulate to thicken the mixture that forms yogurt. Blood platelets coagulate blood to seal a wound. Pectin gels (coagulates) a jam. Gravy coagulates as it cools. Sources David Lillicrap; Nigel Key; Michael Makris; Denise O'Shaughnessy (2009). Practical Hemostasis and Thrombosis. Wiley-Blackwell. pp. 1–5. ISBN 1-4051-8460-4.Pallister CJ, Watson MS (2010). Haematology. Scion Publishing. pp. 336–347. ISBN 1-904842-39-9.