Before revision:  The resulting dynamics are highly diverse, lead to local calcium "puffs" as well as global waves propagating through cells {\it   . Local fluctuations in the number of calcium ions play a crucial role in the onset of these features.
After revision:  The resulting dynamics are highly diverse, lead to local calcium ``puffs'' as well as global waves propagating through cells {\it . Local fluctuations in the number of calcium ions play a crucial role in the onset of these features.