Renal Flashcards
(157 cards)
how much of the cardiac output goes to the kidneys
20%
how many nephrons are found in each kidney
1,000,000
what are the 4 stages of kidney function
Glomerular Filtration (glomerolus)
Tubular re-absorption (descending)
tubular secretion (ascending)
water-reabsorption (collecting tube)
explain glomerular filtration (2)
water and solutes move from blood into nephrons.
Important that glomerolus retains plasma proteins and blood cells to avoid these passing to the urine.
explain tubular re-absorption
useful substances move from filtrate into blood
explain tubular secretion
wastes and excess substances move from blood into filtrate
what are the 4 main importance’s of the kidney
Salt and water homeostasis
Excretion of waste
Humoral regulation of other organs - producing or modifying several hormones (vit D, renin, Erythropoietin)
Selectivity barrier - prevention of blood into the urine
what are the 3 major hormones regulated by the kidney
Vitamin D = bone
Red blood cells (Erythropoietin)
Blood vessels (Renin)
if kidney damage altered salt and water retention, what 3 main changes would we see to a pt
Changes in total body water
Changes in blood pressure
Changes in urine volume or concentration
what problems can come if excretion of waste by the kidneys is altered (4)
Uraemia - breakdown of proteins = high urea in blood
Acidosis eg lactic acid, ketoacids not being removed = pH of blood change
Others: Potassium, Phosphate, Uric acid = many patients gain hyperkalaemia
Reduced clearance of drug
if there is barrier failure in the kidney, what might we find in the urine (3)
Haematuria - blood
Proteinuria - protein
Lipiduria - lipids
what is GFR
glomerular filtration rate
what two values can we get, based on GFR
estimated GFR (most common)
measured GFR (if severe case, more accurate)
how do we estimate GFR
testing concentration of urea in the blood
what is a normal and a healthy range of GFR
normal is 120ml/min and ‘healthy range’ is 60-120 ml/min
what GFR counts as severe life threatening, kidney disease and ‘normal’
<15 = life threatening
15-60 = kidney disease
60-120 is normal
what does an estimated GFR < 60 indicate (2)
renal disease
take a MEASURED GFR to get more accurate
when do we take a measured GFR and why
when the estimated GFR is < 60
need a more accurate finding to classify renal disease
and for better monitoring
what are the main three clinical consequencs of renal disease
Hypertension
Anaemia
Renal Bone disease
explain renal hypertension (2)
Kidney is important for producing renin in the renin-angiotensin aldosterone system for controlling hypertension
Also for volume of fluid in blood which alters blood pressure (ADH)
at what point in renal failure do we start seeing anaemia (2)
GFR < 30mil/min
at GFR < 5mil/min we see anaemia in every pt
how do we treat renal anaemia
weekly injections of EPO
explain renal rickets
Vitamin D can be made at the skin but has to be activated in a2 step process, with the final step being in the kidney
if not completed, vitamin D cannot aid the absorption of calcium and to keep calcium serum levels correct, the body is forced to take calcium from the bones through resorption
This leads to reduced calcium in bones and weak, brittle, bendy bones
this is rickets caused by the kidney
how od we treat mild/moderate renal failure (3)
moderate/mild = 60 < GFR < 15
diet - so body doesn’t have to remove toxins e.g. less protein
Supplements- Alkali (sodium bicarbonate to prevent acidosis), activated Vitamin D, IV Iron (as liver/kidney disease reduces absorption from the gut)
Drugs for – Hypertension, Anaemia