system
Given the following post, respond as if you're commenting on Reddit:
human
Why does necrotic tissue appear black?
gpt
It doesn't have to be black; in fact, most types of necrosis found in the body do not appear black grossly. Dry gangrene is usually what people think of when they think of necrosis, but that is only one subtype and that is black usually due to trapped blood in the affected tissue. However, there are various other types of necrosis, namely: coagulative, liquefactive, fat, caseous, gummatous, hemorrhagic, and fibrinoid necrosis. Each type operates by totally different mechanisms and have their own unique appearances.