5.3 Kidney Failure Flashcards
what are 3 reasons for kidney failure?
kidney infections
raised blood pressure
genetic conditions
how can kidney infections cause kidney failure?
damage to podocytes and tubules
how can raised blood pressure cause kidney failure?
damage structure of epithelial cells and basement membrane of bowman’s capsule
how can genetic conditions cause kidney failure?
polycystic kidney disease - healthy kidney tissue replaces with cysts or damaged from pressure of cysts
if kidneys are affected by high blood pressure what can be found in urine?
protein or blood
why can protein be found in urine if kidneys are affected by high pressure?
if basement membrane or podocytes are damaged they no longer act as filters so large proteins can pass into filtrate and urine
blood in the urine indicated what isn’t working?
filtering process
if kidneys completely fail it can lead to loss of electrolyte balance, why?
body cannot excrete excess sodium, potassium and chloride ions causing osmotic imbalances and eventual death
if kidneys completely fail it can lead to build up of urea in the blood, what can this do?
poison the cells
if kidneys completely fail it can lead to high blood pressure why?
the kidneys play an important role in controlling bp by maintaining osmotic balance of blood
if kidneys completely fail it can lead to high blood pressure which can lead to what?
heart problems and strokes
if kidneys completely fail it can lead to weak bones, why?
calcium phosphorus balance in blood is lost
if kidneys completely fail it can lead to pain and stiff joints, why?
abnormal proteins build up in blood
if kidneys completely fail it can lead to anaemia, why?
kidneys involved in producing erythropoietin which stimulates rbc formation, kidney failure reduces rbc production
(GFR) what is GFR?
glomerular filtration rate
(GFR) what is the GFR used as a measure to indicate?
kidney failure
(GFR) kidney problems almost always affect what?
blood filtration rate in Bowmans capsule
(GFR) a blood test measures level of what in the blood?
creatine
(GFR) what is creatine and what does it give an estimate of?
breakdown product of muscles
glomerular filtration rate
(GFR) if levels of creatine increase what is it a sign of?
kidneys not working
(GFR) what do normal GFRs not fall below?
70
(GFR) it is kidney failure when GFR falls below what?
15 - kidneys are filtering so little they are virtually ineffective
(haemodialysis) this dialysis uses what?
a dialysis machine
(haemodialysis) blood leaves patient via artery into dialysis machine where it flows between what?
partially permeable dialysis membranes
(haemodialysis) what do the partially permeable dialysis membranes mimic?
the basement membrane of the bowman’s capsule
(haemodialysis) on the other side of the basement membrane what is there?
dialysis fluid
(haemodialysis) in dialysis it is vital patients lose what?
excess urea
(haemodialysis) in dialysis it is vital patients retain useful substances such as what?
glucose
some mineral ions
(haemodialysis) loss of substances in dialysis is controlled by what?
the dialysis fluid
(haemodialysis) what does the dialysis fluid contain normal levels of and why?
plasma levels of glucose to ensure there is no net movement of glucose out of blood
normal mineral ion levels so any excess moves out of blood into dialysis fluid restoring electrolyte balance
(haemodialysis) what does dialysis fluid contain none of and why?
urea
creates steep concentration gradient so urea leaves blood into dialysis fluid
(haemodialysis) why do blood and dialysis fluid flow in opposite directions?
to maintain a countercurrent exchange system and maximise exchange
(haemodialysis) how long does the dialysis take and how often does it have to be repeated?
8 hours, several times a week
(haemodialysis) what do patients on dialysis have to monitor carefully?
fluid intake
diet - little protein and salt
(peritoneal dialysis) what does peritoneal dialysis make use of?
natural dialysis membranes formed by lining of abdomen (peritoneum)
(peritoneal dialysis) using a catheter what happens to the dialysis fluid?
introduced to abdomen
(peritoneal dialysis) how does peritoneal dialysis work?
left for hours, urea and excess mineral ions pass out of blood into tissue fluid and out across peritoneal membrane into dialysis fluid
(peritoneal dialysis) what happens to the fluid after?
drained of and discarded
(transplant) a healthy donor kidney is placed in the body, what is joined?
blood vessels
ureter inserted into bladder
(transplant) what is the main issue of transplants?
risk of rejection
(transplant) how is risk of rejection reduced?
antigens of donor organ and recipient matched as closely as possible
immunosuppressant drugs to prevent rejection
(transplant) if the immune system recognises that the antigens of the donor organ are different what can it result in?
rejection and destruction of the new kidney
(transplant) what is a disadvantage of immunosuppressant drugs?
prevent immune system responding effectively to infectious disease - have to take great care
(transplant) the average transplanted kidney functions how long?
9-10 years
what is more available dialysis or donor organs?
dialysis
what is the main source of donor organs?
from those who die suddenly carrying an organ donor card
what is an issue of long term dialysis?
expensive
damage
there is hope new kidneys can be grown from what?
stem cells perhaps without antigens that trigger the immune system
