2010-02-22 [sheldoncomics.com]

Phloem bundles.

Part of the fibrovascular system that transports soluble organic nutrients like sugars to where they're needed.

Regarding the gastrointestinal part - ah, you must have eaten shrimps... (There's probably a reason it's colloquially referred to as the "bananus", short for banana's anus. No idea if there's a scientific name.)

Here's a tip: Do not imagine the act of its removal as "deveining [wikipedia.org]" your banana. (you're welcome) Aren't euphemisms wonderful?

Peeling the banana from the "bottom" rather than the stem eliminates both the stringy thingies and the nub.

On the banana tree the "bottom" is actually the top of the fruit because the banana fruit grows upwards from the stem.

Pro-bottom-peelers like to point out that monkeys peel bananas from the "bottom" rather than from the stem, but that may not be 100% factual (video exists of monkeys doing it both ways, but the "bottom"-peeling videos are predominant).

The ultimate insult in my wife's family growing up was to call someone "the little black part at the end of the banana"... it pretty much meant useless, with a twinge of you disgust me