You have done a great job sir breaking apart the crankshaft, but allow me make some contributions.

The crankshaft is the backbone of any internal combustion engine. it collects power from the piston through the connecting rod and distribute it to other parts. Its rigidity and stability is important and this is afforded by the bearings.

The lubrication of this bearings is important and this is done by channelling lubricaion oil via tiny holes in the crankshaft to these bearings. These holes are called the Oil gallery.

I hope you don't mind.
Best wishes!