For further details see also The confusing variety of platelet receptors . The proximity to the MTS suggests its origin as a smooth endoplasmatic reticulum, analog to the sarcoplasmatic reticulum in muscular tissue. Surrounding the organelle zone is a membrane system with invaginations of the platelet's plasma membrane. Organelles Organelles are almost evenly distributed in the cytoplasma of resting platelets. Mitochondria serve as energy source, since resting platelets cover their energy expenditure by oxidative phosphorylation, similar to other cells.
Dense bodies contain calcium, serotonin, adenine nucleotides, etc.
Following activation platelets release their granula contents, contributing to diverse interactions with other platelets or other cells.