15.8 Kidney failure Flashcards
(16 cards)
What are the causes of kidney failure
- Damaged structures
(E.g Bowman’s capsule, podocytes, basement membrane) - Genetics
(E.g polycystic kidney disease)
What are the effects of infection/high blood pressure on the kidneys?
• Protein/erythrocytes in urine
(∵ basement membrane/podocytes are DAMAGED from high pressure, no longer act as FILTERS, allow LARGE MOLECULES through to filtrate)
What are the effects of kidney failure
- ￪ UREA concentration (urea cannot be excreted, builds up)
-Imbalanced ELECTROLYTES (excess ions not excreted, leads to osmotic imbalances)
-High BLOOD PRESSURE (excess ions decrease water potential, water moves in, increased hydrostatic pressure)
-WEAKENED BONES (imbalanced calcium + phosphorus)
-PAIN + STIFFNESS (build up of abnormal proteins in blood)
-ANAEMIA (kidneys no longer produce enough erythropoietin, cannot make enough erythrocytes)
Why is increased urea conc an effect of kidney failure
Urea can no longer be excreted therefore it builds up
Why is an imbalance of electrolytes an effect of kidney failure
Excess ions (K+, Na+, Cl-) cannot be excreted.
leads to osmotic imbalances + eventual death
Why is high blood pressure an effect of kidney failure
Excess ions (which cannot be excreted) decrease water potential of blood
water moves in from surrounding tissue by osmosis
increases hydrostatic pressure of blood
Why is weakened bones an effect of kidney failure
Imbalanced calcium and phosphorus
responsible for healthy bones and teeth
Why is pain and stiffness an effect of kidney failure
Accumulation of abnormal proteins in the blood
which would otherwise be excreted
Why is anaemia an effect of kidney failure
Kidneys are involved in production of erythropoietin,
which makes erythrocytes.
Failed kidneys dont produce enough erythropoietin,
∴ not enough erythrocytes (anaemia)
What’s the glomerular filtration rate an indicator of and how is it measured
It’s an indicator of kidney function and its measured indirectly by measuring creatinine levels (high levels is a sign of kidney failure)
What is creatinine and how is it useful
product of muscle breakdown.
Creatinine levels in blood measured to indicate glomerular filtration rate.
(Since usually filtered out of blood by kidneys, an abnormal level of creatinine in the bloodstream indicates insufficient kidney function + possible disease)
What must be taken into account when measuring GFR using creatinine
Other factors affecting creatinine levels eg. age, gender, exercise levels
What’s are the two treatments for kidney failure
- Dialysis
- Transplant
Haemodialysis
Uses a dialysis machine only useses diffusion
Usually done in hospital takes about 8 hours
Done outside the body - blood leaves the body through an artery and flows into the dialysis machine
Blood thinners are used to prevent clotting
The machine has the same conc of mineral ions and glucose as normal blood with no urea so there’s a steep urea conc so it all diffuses from the blood to dialysis fluid. There are conc gradients so excess salts diffuse out of the blood, the membrane is partially permeable (mimicking a basement membrane before the blood returns to the body if flows through a bubble trap to get rid of any air bubbles repeats are needed often and the patients diet must be managed little salts and protein
Pros and cons of kidney transports
Pros
More freedom
No longer have kidney problems
Don’t need to control diet
Cons
Risks of infections or rejection (not recognising antigens on donor kidney)
Have to take immunosuppressants
Kidneys not readily available
Pros and cons of dialysis
Pros
No risk of injection
Readily available
Prevents urea build up
Cons
On blood thinners
Expensive
Control diets
Have to spend lots of time attached to a machine
Lots on needles to get blood out can cause infection
