Autolysis is the enzymatic digestion of cells by their own lysosomal enzymes, which usually occurs in dying or dead cells. It happens after cell death, in areas with ulcers, fibrosis, cuts, or ischemic changes. Autolysis is caused by lysosomal enzymes alone, while apoptosis can be triggered by injury, free radicals, and other causes and involves regulated genetic pathways rather than just enzymatic digestion.