Please enable JavaScript.
Coggle requires JavaScript to display documents.
12.4 Dialysis - An Artificial Kidney - Coggle Diagram
12.4 Dialysis - An Artificial Kidney
Kidney failure
Kidneys may fail because of infection, genetic problems or damage
Urea can build up in the blood
Water and mineral ion balance is no longer maintained
Can cause serious damage to cells
Treatments include dialysis or a kidney transplant
Dialysis
Carries out the function of damaged kidneys artificially
Blood leaves the body and passes through a dialysis machine
Blood is separated from dialysis fluid by a partially permeable membrane
Dialysis must be repeated regularly
How dialysis works
Dialysis fluid
Contains normal concentrations of glucose and mineral ions
Contains no urea
Prevents useful glucose and mineral ions being lost from the blood
Removing urea
Blood has a high urea concentration
Dialysis fluid contains no urea
Urea diffuses from the blood → dialysis fluid
Moves down a concentration gradient
Removing excess mineral ions
Excess mineral ions diffuse from blood → dialysis fluid
Move down a concentration gradient
Partially permeable membrane
Allows small dissolved substances to pass through
Blood cells and large proteins cannot pass through
Flow of fluid
Blood and dialysis fluid continuously flow
Maintains concentration gradients
There is no active transport
Disadvantages of Dialysis
However, dialysis can keep someone with kidney failure alive
Blood chemistry can become harder to control over time
Diet has to be carefully controlled
Patient may feel tired or unwell between sessions
Regular, long dialysis sessions
Managing dialysis
Salt intake must be controlled because damaged kidneys cannot remove excess mineral ions effectively
Protein intake must be controlled to reduce urea build-up
Usually needed several times a week
Takes around 8 hours