Cellular Aging and Apoptosis

Intrinsic and Extrinsic Apoptotic Pathways

Cellular aging is an essential biological process that leads to gradual functional decline and eventual cell death. Apoptosis, or programmed cell death, plays a critical role in maintaining cellular homeostasis by eliminating damaged or aged cells. There are two primary apoptotic pathways: intrinsic and extrinsic.

Intrinsic Apoptotic Pathway

The intrinsic pathway is triggered by internal cellular stress, such as DNA damage or oxidative stress. It is regulated by mitochondrial activity and involves proteins like Bcl-2, Bax, and cytochrome c, leading to caspase activation and cell death.

Extrinsic Apoptotic Pathway

The extrinsic pathway is initiated through extracellular signals binding to death receptors on the cell surface. Key receptors include Fas and TNF receptor, which activate caspase cascades leading to apoptosis.

Significance in Pathology

Understanding apoptotic mechanisms is crucial in pathology, particularly in diseases like cancer, where apoptosis evasion contributes to uncontrolled cell proliferation.