system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Where does my bellybutton go?

ELI5:I know that it was my source of nourishment in the womb but now that I’ve been out of there for a few decades, where does it go? Is it still connected to something inside my abdomen or have the muscles )and I use that word loosely) separated it from my “insides”?
gpt
Medical student here

Your belly button is the artifact left behind of your umbilical cord. Once you are birthed, they snip the cord a few inches off the base. After a few days it drys up and falls off because no nutrients are being received. 

The inside part of the cord is connected to the bladder, the gut, and the main vein that goes to the heart called the Vena Cava. Since your body has no need for those structures, they just get broken down by the body. Sometimes, they aren’t fully broken down and can cause a cyst or a full on opening such as a Meckel’s diverticulum or Patent Urachus. Usually these need to be closed or removed surgically.