Mature circulating platelets are packed with dense granules containing atp , adenosine diphosphate ( adp ) , and calcium , as well as serotonin , lysosomes , glycogen , mitochondria , and an intracellular canalicular system .

成熟的血小板内挤满了含有atp、二磷酸腺苷（adp）的致密颗粒，以及钙、血清素、溶酶体、糖原、线粒体和细胞内微管系统。