In a dialysis machine, why is it important that the membranebetween the blood and dialysisfluid is partiallypermeable?
To only allow some substances to diffuseacross
In a dialysis machine, why is it important to continuallypumpfreshdialysisfluid through the machine?
To maintain a concentration gradient for diffusionacross the membrane
Will fresh dialysis fluid contain urea?
The dialysisfluid contains the 'ideal' concentration of each substance, so won't contain any urea.
If a person has too much sodium in their blood, which way will the sodium diffuse during dialysis?
From their blood into the dialysisfluid
Dialysis fluid contains the same concentration of usefulsubstances as healthyblood.
What are the downsides of dialysis?
It is timeconsuming
There is a risk of infection
It is expensive to run
A living person can donate a kidney because we are all born with two.
If a patient has a kidney transplant, what type of drugs are they required to take for the rest of their lives?
Immunosuppressants
Rejection of a transplanted organ
The main risk with kidney transplants is that the organ will be rejected
This can happen because the body's immune system treats the transplantedorgan as a foreignobject, and so tries to destroy it.
We can reduce the risk of this happening by using medications to suppress the immunesystem.
In the long term, which is cheaper: a kidney transplant, or dialysis?
kidney transplant
Dialysis is more expensive because it involves continuedtreatment every week for the rest of the person's life. In contrast, transplants just involve an initialsurgery and then continued taking of medicines (which are relatively cheap).