Dialysis blocks the passage of larger substances (for example, red blood cells, large proteins). This replicates the filtering process that takes place in the kidneys when the blood enters the kidneys and the larger substances are separated from the smaller ones in the glomerulus. The two main types of dialysis, hemodialysis and peritoneal dialysis, remove wastes and excess water from the blood in different ways. Hemodialysis removes wastes and water by circulating blood outside the body through an external filter, called a dialyzer, that contains a semipermeable membrane. The blood flows in one direction and the dialysate flows in the opposite.
Organ procurement like organ theft or organ trade, fair organ distribution, and to a lesser degree, animal rights and religious prohibition on consuming some animals such as pork. There is a shortage of organs available for donation with many patients waiting on the transplant list for a donation match. About 20 patients die each day waiting for an organ on the transplant list. When an organ donor does arise, the transplant governing bodies must determine who receives the organ. The UNOS computer matching system finds a match for the organ based on a number of factors including blood type and other immune