The apoptosis pathway mainly divides into two types: extrinsic and intrinsic pathways. The extrinsic pathway is typically triggered by the activation of death receptors, which are specific proteins on the cell surface that can recognize extracellular death signal molecules. When these receptors are bound by their ligands, they promote the formation of a death-inducing signaling complex, activating downstream members of the Caspase enzyme family, thereby initiating the apoptosis program. The intrinsic pathway, on the other hand, is triggered by internal stress and damage signals, especially when there is an imbalance within the cell environment (such as DNA damage or oxidative stress). These signals usually act by affecting the permeability of the mitochondrial outer membrane, releasing pro-apoptotic factors such as cytochrome c into the cytoplasm, activating the Caspase cascade, and ultimately leading to cell death.