Guide tube systems and methods

A medical system comprising:

• a guide tube including a body extending from a proximal end to a distal end, the body including a first working channel that terminates at a first distal opening, a second working channel that terminates at a second distal opening, a third working channel, a fourth working channel, and an articulation portion proximate the distal end, wherein the distal end includes an end cap, and the guide tube further includes a housing member at the proximal end with controls coupled to the articulation portion via a plurality of control wires, wherein a proximal portion of the first working channel passes through an aperture of the housing member distal to the controls, a first proximal opening of the first working channel being proximal to the controls;
• and
• a first instrument slidably disposed within the first working channel;
• wherein the end cap includes a cover configured to selectively close and open at least one of the first distal opening or the second distal opening;
• and
• wherein the guide tube includes a diverging mechanism that adjusts an amount of divergence between the first working channel and the second working channel distal to the articulation portion, such that the first and second working channels are closer to each other at a middle portion of the guide tube than at either the proximal end or the distal end of the guide tube.