A proximal terminal end of a proximal section of a catheter, preferably tapered, defines a perimeter of an opening into a lumen of the catheter and includes an exposed sealing area. A sealing assembly, that may be removed from the catheter, includes a relatively soft part and a relatively rigid part, wherein the exposed sealing area is formed by the soft part, and the relatively rigid part may include an attachment feature for removable connection of the assembly to the catheter. The lumen of the catheter, within the proximal section, may include a seal zone portion, which preferably includes a slit segment intersecting a funnel-like segment of a bore. The catheter proximal section may further include a feature for interlocking engagement with an accessory tool.