Nice article in the New York Times today about the spleen. It's one of those organs that we didn't know what it was used for, so we assumed it wasn't that important. We just didn't know what it did. It turns out that a specific immune cell type (monocytes) hangs out in the spleen, ready to be injected into the bloodstream and go help out where there's sudden damage, like in a heart attack. The spleen is a staging ground for a "standing army" of monocytes.
Here's a great quote:
“Often, if you come across something in the body that seems like a big deal, you think, ‘Why didn’t anybody check this before?’ ” Dr. Nahrendorf said. “But the more you learn, the more you realize that we’re just scratching on the surface of life. We don’t know the whole story about anything.”
Good news for those of us who scratch that surface for a living!