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 urinary catheter is a flexible plastic tube used to drain urine from your bladder when you cannot urinate by yourself. A doctor will place the catheter into the bladder by inserting it through the urethra, the opening that carries urine from the bladder to the outside of the body. When the catheter is in the bladder, a small balloon is inflated to keep the catheter in place. The catheter allows urine to drain from the bladder into a bag that is usually attached to the thigh.