During dialysis, what process is
involved in the movement of waste substances out of the blood and into the dialysis
fluid? (A) Translocation, (B)
transpiration, (C) diffusion, or (D) active transport.
If a person is suffering from
kidney failure, they may be offered dialysis. The main aim of dialysis is to
replace the function of the kidneys. Our kidneys are essential in
removing waste products, like urea, from our blood. If a person’s kidneys start to
fail, they often experience a buildup of waste products in their blood. Let’s have a closer look at how
dialysis works in removing these waste products from a person’s blood.
During dialysis, the patient is
connected to a dialyzer. Blood is removed from the patient’s
arm via an artery, passed through pressure monitors and blood pumps, before being
moved into the dialyzer itself. The dialyzer has a constant supply
of fluid called dialysate. In the dialyzer, waste products in
the blood that have built up as a result of the kidneys not functioning properly
move from the blood and into the dialysate. So by the time the blood then
reenters the patient’s arm, it is clean.
In the blood that enters the
dialyzer, there is a high concentration of waste products. In the dialysate, however, there is
a very low concentration of waste products. Therefore, the waste products move
from an area of high concentration to an area of low concentration.
We know that diffusion is the
passive movement of molecules down their concentration gradient, from an area of
high concentration to an area of low concentration. So our correct answer must be
(C). The process involved in the
movement of waste substances out of the blood and into the dialysis fluid is