Lecture 4: Formation of Urine 2 Flashcards
in which parts of the loop of henle are water and ions extracted
- descending limb: extraction of water
- ascending limb: extraction of Na+ and Cl-
what is present on the descending limb of the loop of henle
aquaporin 1 channels
what is present on the ascending limb of the loop of henle
NKCC2 cotransporters
what is the osmolality of an isotonic solution
300 mOsm
what are principal cells sensitive to
aldosterone
which cells detect drop in sodium levels
macula densa cells
which cells secrete renin in the kidneys
juxtaglomerular cells
what do alpha intercalated cells do
- secrete H+
- absorb Na+
- via Na+/H+ pump
- secrete Cl-
- reabsorb HCO3-
- via Cl-/HCO3- pump
what do beta intercalated cells do
- secrete HCO3-
- absorb H+
- via pendrin
- not as common or important as alpha ones
what effects does ADH have on the collecting duct
- acts on vasopressin V2 receptors
- on basal membrane of principal cells in DT and collecting duct cells
- activating aquaporin 2 channels
what condition arises from lack of ADH
diabetes insipidus
how much urine does maximum ADH produce
300 ml per day
how much urine does minimum ADH produce
30 l per day
what causes nephrogenic diabetes insipidus
inability of kidneys to respond normally to ADH
what causes neurogenic diabetes insipidus
lack of ADH production by the brain
what is treatment of nephrogenic diabetes insipidus
- chlortalidone
- indometacin
what is treatment of neurogenic diabetes insipidus
- desmopressin
- vasopressin
- carbamezapine
what happens in syndrome of inappropriate ADH
- excessive release of ADH
- due to head injury or ecstasy use
- treatment is V2 receptor blockers, eg demeclocyclin and tolvapran
agents that increase ADH release
- nicotine
- ether
- morphine
- barbituates
agents that decrease ADH release
alcohol
where do all the reabsorbed solutes and water go
- peritubular vessels
- vasa recta
