We only recently learned that the peritoneum is an organ too.
Thank you for posting this
I feel like we still have lots to uncover/discover about our bodies. They are such fascinating things, a delicate balance. Look at the stomach for instance, the acid in our stomach is hydrochloric acid & digestive enzymes.
We don't even understand the full scope of Ghrelin (a.k.a Hunger hormone) & how it makes us hungry.