Hypoxia and Medicine

During ischemia, why do cells accumulate cytoplasmic calcium?

Public Comments

1. Physiological levels of calcium in the cytoplasm are around 1uM (1 microMolar). Calcium in excess is either actively pumped inside the Endoplasmic Reticulum for storage purposes, or pumped out the cell. These pumps function thanks to ATP. Now, what happens during ischemia is that an aera is deprived of blood, therefore no oxygen reaches it. With no oxygen entering cells, mithocondria cannot function and cannot produce ATP. So in the end you have: ischemia -> no blood -> no oxygen -> mithocondria not working -> ATP not produced -> ATP-dependent Calcium pumps not working -> Calcium enters cells and accumulates in cytoplasm without chance of being pumpd out anymore.