The plasma membrane forms a barrier against excessive amounts of Na+ within the extracellular fluids from entering the cell. However, the plasma membrane is slightly “leaky” to Na+, allowing minimal amount of Na+ to gradually move into the cell. To compensate this, there is a perpetually active Na+/K+ ATpase pump, which move Na+ out of the cell constantly, in exchange for K+ into the cell. The normal functioning of these pumps is hampered due to depletion of ATP which leads to accumulation of Na+ intracellularly creating osmotic pressure which causes cellular swelling.
Fatty Change (Steatosis): This Steatosis is caused in hypoxic, toxic and metabolic injuries and is related to a dysfunction in the cell’s regulation of synthesis and elimination of triglycerides. Excess lipids accumulate within the cells, usually parenchymal cell that form numerous vacuoles that displace the cytoplasm. if these vesicles are large enough to displace and distort the nucleus, it is referred to as macrovesicular Steatosis.