Kidney treatments Flashcards
What is kidney failure?
when the kidney stops working properly
excess mineral ions, water and urea build up in the body
How can people with kidney failure be treated?
dialysis or a healthy kidney transplant
How often does dialysis have to be carried out?
2 or 3 days, in a hospital
Describe the process of dialysis.
unfiltered blood high in waste substances taken from blood vessel in arm
mixed with blood thinners/anticoagulant to prevent clotting
pumped into dialysis machine
clean blood is passed through an air trap and detector to remove air
clean blood is returned to patient
Describe how a dialysis machine works
dialysis fluid is fed in and removed to the machine
the blood and dialysis fluid are separated by a partially permeable membrane
blood flows in opposite direction to dialysis fluid
concentration gradient
exchange of substances occurs naturally
there are rows of dialysis fluid to give more surface area for exchange of substances
Describe how glucose in dialysis fluid works
glucose concentration similar to a normal blood level
an equal concentration prevents the net movement of glucose across the partially permeable membrane
because no concentration gradient exists
important as patient needs to retain glucose for respiration
(too much glucose or too little causes problems)
Describe how urea in dialysis fluid works
no urea
large concentration gradient
urea moves across partially permeable membrane by diffusion to the dialysis fluid
important as urea is toxic and needs to be removed from patient’s blood
Describe how mineral ions/water in dialysis fluid works
concentration of mineral ions/water similar to normal blood plasma
the concentration is equal to normal levels
movement of ions/water only occurs when there is an imbalance
- too high, blood -> fluid
- too low, fluid -> blood
advantages of dialysis
person with kidney failure can maintain health
greatly reduced levels of urea
no change in blood glucose
correct water and ion balance maintained
available to all kidney patients
no immune suppressant drugs
disadvantages of dialysis
highly specialised and expensive machinery (expensive for NHS)
time consuming and restrictive
(2-3 a week, 4-6 hours)
filtration only when connected
diet must be monitored carefully between sessions
(avoid foods with high salt or protein content as amino acids break down into urea)
only works for a limited time before a transplant is needed, many patients die before one is found
State what kidney transplant involves
a healthy organ is donated by a donor and transplanted into a patient
better than dialysis as patient can live a normal life afterwards
a healthy kidney is connected to the blood circulation to do the work of the diseased kidneys
antigens
a foreign organism that gets into the body and triggers an immune response
problems with kidney transplant rejection
donor kidney cells have protein antigens on surface
antigens are unique, allow body to identify cells from pathogens
differences in antigens of donor kidney cells and patient cause immune response
antibodies attack and destroy kidney
(organ rejection)
How is kidney rejection prevented?
-tissue typing
similar antigens are found
leads to long waits while compatible donors become available
patients waiting undergo dialysis, and often die
-immuno-suppressant drugs
taken by patients for rest of lives
suppress immune system, reducing response against kidney
also suppresses response against pathogens, increasing risk of infections
How long do most donor kidneys last for?
8-9 years
patient then requires further transplant or dialysis
