5.2.8 kidney failure Flashcards
define glomerular filtration rate (GFR)
rate at which fluid enters the nephrons
define monoclonal antibodies
antibodies made from 1 type of cell (specific to 1 complementary molecule)
define renal dialysis
mechanism used to artificially regulate concentrations of solutes in blood
what happens if kidneys fail
unable to regulate levels of water/electrolytes or remove waste products (eg. urea) = death
how can kidney function be assessed
- estimating glomerular filtration rate (GFR)
- analysing urine for substances (eg. proteins)
normal reading for glomerular filtration rate
90-120 min3 cm-1
what does a GFR below 60 cm3 min-1 indicate
may be some form of chronic kidney disease
what does a GFR below 15 cm3 min-1 indicate
kidney failure & need for immediate medical attention
possible causes of kidney failure
- diabetes mellitus
- heart disease
- hypertension
- infection
what is renal dialysis
- waste products, excess fluid & mineral ions removed from blood by passing over partially permeable dialysis membrane
- allows exchanges of substances between blood & dialysis fluid
- dialysis fluid contains correct concentrations of mineral ions, urea, water & other substances found in blood plasma
- any substance in excess in blood diffuses into dialysis fluid
- any substance too low in concentration in blood diffuses from dialysis fluid
type of renal dialysis
haemodialysis
describe haemodialysis
- blood from artery/vein passed into machine containing artificial dialysis membrane shaped to form many capillaries = increases SA for exchange
- heparin added to avoid clotting
- artificial capillaries surrounded by dialysis fluid, flowing in opposite direction to blood (countercurrent) = improves efficiency of exchange
- any bubbles removed before blood returned to body via vein
when is haemodialysis usually performed
at a clinic 2-3 times a week for several hours at each session
–> some learn to do it at home
types of treatment for kidney failure
- renal dialysis
- kidney transplant
describe kidney transplants
- new organ implanted in lower abdomen & attached to blood supply/bladder
- immunosuppressant drugs given to prevent immune system rejecting it
advantages of kidney transplants
- freedom from time-consuming renal dialysis
- feel physically fitter
- improved quality of life (eg. able to travel)
- improved self-image (no longer feel chronically ill)
disadvantages of kidney transplants
- take immunosuppressant drugs
- major surgery under general anaesthetic
- need regular checks for signs of rejection
- side effects of immunosuppressant drugs (eg. fluid retention, high blood pressure, susceptibility to infections)
what can urine be tested for
- glucose for diagnosis of diabetes
- alcohol to determine blood alcohol levels in drivers
- many recreational drugs
- human chorionic gonadotrophin (hCG) in pregnancy testing
- anabolic steroids to detect improper use in sports
how is urine analysis used for pregnancy testing
- hCG is relatively small glycoprotein & has molecule mass of 36,700
- can be found in urine as early as 6 days after conception
- pregnancy-testing kits use monoclonal antibodies to bind to hCG
steps of pregnancy testing kits
- urine poured onto test stick
- hCG binds to mobile antibodies attached to blue bead
- mobile antibodies move down test stick
- if hCG present, it binds to fixed antibodies holding bead in place = blue line
- mobile antibodies with no hCG attached bind to another fixed site to show test is working
how is urine analysis used to test for anabolic steroids
- anabolic steroids increase protein synthesis in cells = build-up of cell tissue
- anabolic steroids have half-life of roughly 16 hours & remain in blood for many days
- relatively small molecules & can easily enter nephron
- testing = analysing urine sample in laboratory using gas chromatography
