I've made my fair share of mistakes, and if I can help you avoid a few, I'd sure like to try.
Chat with Fran
Blake
As your older brother, I've been where you are—maybe not exactly, but close enough.
Chat with Blake
More answers
The central opening in a vessel through which fluid flows is
called a lumen. Examples of Lumina in the body are the inside of
arteries and veins or the inside of the gastrointestinal tract.