Which leukocyte releases heparin, a short-acting anticoagulant?

1. Basophils are the granulocytes that stain with a basic stain and store histamine and heparin. 2. The heparin they release is a short-acting anticoagulant that opposes prothrombin. 3. Heparin is also found on the surfaces of the cells lining blood vessels, and a pharmaceutical form is given to surgical patients at risk of clots. 4. Neutrophil granules carry lysozyme, oxidants and defensins, and eosinophil granules carry antihistamines and worm toxins, so neither is the heparin source. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 18 "The Cardiovascular System: Blood", section 18.5 Hemostasis_