Many people use the terms ocean and sea interchangeably when speaking about the ocean, but there is a difference between the two terms when speaking of geography (the study of the Earth's surface).
The peritoneal dialysis catheter is composed of a flexible silicone tube with an open-end port and several side holes to provide optimal drainage and absorption of the dialysate. The extraperitoneal component of the catheter has either one or two Dacron cuffs. The Dacron cuffs are for optimal ingrowth and fixation.
A catheter is a hollow tube that is inserted into the bladder through the urethra to remove urine from your bladder. It can be left in place for hours or days to alleviate your need to go to the bathroom or to use a bedpan if you are restricted to bed or are numb and can't feel the need to urinate.