HSC 4555 Lecture Notes - Lecture 4: Apoptosis, Cellular Adaptation, Reperfusion Injury
Document Summary
Cellular responses to reversible injury, regardless of the cause, often result in cellular swelling and the accumulation of excess substances within the cell. These changes reflect the cell"s inability to perform normal metabolic functions owing to insufficient cellular energy in the form of adenosine triphosphate (atp) or dysfunction of associated metabolic enzymes (pgs. Reversible and irreversible cellular injuries are differentiated by the cell"s ability to adapt or repair. In reversible injuries, hydropic swelling and intracellular accumulation typically resolve when the causative factors are removed. As the cell adapts to persistent stress, atrophy, hypertrophy, hyperplasia, metaplasia, and dysplasia may occur, which are potentially reversible when the cellular stress is relieved. However, when the injury is too severe or prolonged to allow cellular adaptation or repair, irreversible cellular injuries cause pathologic cell death, necrosis and apoptosis (pgs. Necrosis is usually a consequence of disrupted blood supply and can result in local and systemic symptoms, including pain, inflammation and loss of function.
