Which of the following produces irreversible cell injury faster?

Ans: c (Ischaemia) Ref: Robbins, 7th ed,p. 12Both hypoxia and ischaemia produces irreversible cell injury by reducing aerobic oxidative respiration, but ischaemia not only compromises the supply of oxygen but also compromises metabolic substrates including glucose (which is normally provided by the blood). Therefore ischaemic injuries are more rapid and severe than hypoxic injuries.Depletion of ATP: ATP depletion and decreased ATP synthesis are frequently associated with both hypoxic and toxic (chemical) injuries. They are slower than ischaemic injury.Increased cytosolic Ca2+: Increase in cytosolic Ca2+ can occur in cell injury due to ischaemia as well as toxins. But it is not specific for irreversible cell injury. It can be found in reversible cell injury also.Also, loss of Ca2+ homeostasis is not always a proximal event in irreversible cell injury.