vessel > [the bladder]
4 Till by a conduit pipe it thence was brought:
conduit pipe > [the urethra]
5 And all the rest, that noyous was, and naught,
noyous > noisome, obnoxious naught > worthless
6 By secret ways, that none might it espy,
that > [so that]
7 Was close conveyed, and to the back gate brought,
close > secretly conveyed > conveyed; removed in an underhand manner back gate > [the anus]
8 That cleped was Port Esquiline, whereby