A small cut won’t bleed for long because tiny blood cells called platelets stick together and trigger clots. Damaged blood vessels and red blood cells release a compound known as adenosine diphosphate, or ADP, which triggers the process that makes platelets sticky.
Sometimes, however, overly reactive platelets are attracted to arteries damaged by fatty buildup.
Log in
Subscribers, enter your e-mail address for full access to the Science News archives and digital editions.