Serous Membrane

As Serosa (actually Tunica serosa, from Latin, means as much as seröse In a broader sense, we refer to all serous skins, i.e. the Pleura, the Peritoneum and the Pericardium. The serosa produces a serum-like liquid and thus prevents the intestines from rubbing against each other due to dryness or ensures that the organs glide freely against each other.

https://de.wikipedia.org/wiki/Tunica_serosa _{(Wikipedia CC-by-sa-3.0)}