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.
In urinary catheterization, a catheter (hollow tube) is inserted into the bladder to drain or collect urine. There are two main types of urinary catheterization: indwelling catheterization and clean intermittent catheterization (CIC).