Are the ventral nerve cord and the ventral blood vessel connceted?

no

Carrys Blood Through The Body

I always got dorsal (down the back or spine) and ventral (down the underside) confused, until I thought of an easy way to remember it. The ventral goes down to where the animal "vents" (poops). So...

it is the main blood flow section of worm antomy. it supplys the organs and brain with blood.