Endocrine impact on renal function Flashcards
Label the nephron
What substances are reabsorbed in the proximal convoluted tubule?
glucose
sodium
water
amino acids
salt
urea
how does the LoH concentrate urine?
Ascending limb:
- active transport of ions out
- impermeable to water
- unconcentrates urine arriving in DCT
Descending limb:
- osmosis (water leaves)
- tubule fluid concentrated
What occurs in the distal convoluted tubule?
reabsorption of water
Why do diabetes patients pee alot?
Too much glucose in blood so excess glucose in kidneys cannot be reabsorbed by tubular cells => draws water into tubules => excess urination
How is water absorption in the collecting duct hormonally controlled?
ADH/vasopressin from pituitary - increase water reabsorption
Aldosterone (RAAS) - increases Na+ reabsorption in exchange for K+ and H+ => increased water volume
Describe the function of the collecting duct
Final stage of water reabsorption
Does most of urine concentrating
What is osmotic diuresis?
excess urination due to presence of substances in kidney filtrate causing water to be drawn into filtrate
what is Fanconi syndrome?
increased glucose in tubules
kidneys cannot reabsorb glucose/proteins/amino acids
(different to diabetes as blood glucose is normal)
Why does chronic renal disease cause polyuria?
insufficient nephrons to handle all filtered salts so osmotic diuresis in available nephrons
Also find azotaemia and dilute USG
What is azotaemia?
increased blood levels of urea or creatinine due to:
- not enough blood being filtered (pre-renal azotaemia)
- or not enough nephrons to filter correctly (renal disease)
What is the USG found in an unfunctioning kidney?
1.008 - 1.012
What is diabetes insipidus?
something stopping the action of ADH (not being made or action blocked) => dilute urine
