AP BIOLOGY

Detailed explanation-1: -The dialysis fluid flows in the opposite direction to the blood. The technical term for this is counter-current flow. This is the best way to remove harmful substances, waste products and excess water from the blood and get rid of them together with the dialysis fluid.

Detailed explanation-2: -Blood is pumped through capillary tubes, while dialysate circulates on the outside of the tubes. The blood pump moves blood from access (fistula, graft, or catheter) to the dialysis machine and back to patient while dialysate is flowing in the opposite direction.

Detailed explanation-3: -Blood enters at one end of the filter and is forced into many, very thin, hollow fibers. As your blood passes through the hollow fibers, dialysis solution passes in the opposite direction on the outside of the fibers. Waste products from your blood move into the dialysis solution.

Detailed explanation-4: -Dialysate Flow Countercurrent flow maximizes the concentration gradient between blood and dialysate throughout the length of the dialyzer (see Box 22.1). When blood flow and dialysate flow are in the same direction (cocurrent), small solute clearance decreases by about 10%.

Detailed explanation-5: -In order to make the removal of waste products from the blood more efficient, blood and dialysis fluid flow in opposite directions inside the dialyzer. This allows a steep concentration gradient between the two fluids to be maintained. So waste products can continually diffuse out of the blood.