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 small plastic tube used to help those unable to use the bathroom urinate. The tube is inserted through the urethra and into the bladder. Urine then empties through the tube into a plastic bag. Catheters can be used both for in-home treatment and in hospitals for patients who are bedridden.