The active elements in intracellular calcium dynamics are release
channels on the membrane of intracellular calcium stores like the endoplasmic reticulum. They are arranged in small groups. Channels are tightly packed within such a cluster. The typical cluster distance is 2-7micrometer.
A single cluster comprises 20-30 channels. The small number of channels
per cluster guarantees that fluctuations are large. Additionally, the large separation of clusters prevents spatial averaging.
We show spatial and temporal structures arising in this genuinely random
medium. Two different lines of evidence suggest that all structures are due to fluctuations since the deterministic limit of the stochastic system is bistable. Bistability arises from spatial discreteness.
Audio requires RealPlayer by RealNetworks.