Figure 5: Schematic representation on the role of mitochondria and SER as intracellular Ca2+ stores and on the cellular death induced by MeHg via Ca2+ dyshomeostasis. (a) Under low cytosolic   [ C a 2 + ] 𝑖   the SER preferentially moves Ca2+ from cytosol due its high affinity and low capacity to stores Ca2+; whereas (b) the mitochondria by presenting low affinity and high capacity to stores Ca2+ moves it under high cytosolic   [ C a 2 + ] 𝑖 ; (c) the disruption of Ca2+ regulation produced by MeHg in either of these stores can lead to release of neuronal proapoptotic factors that may trigger cell death pathways. The scheme presented here is merely representative, and the scale of the different cellular structures does not represent the real size.