Kidney Anatomy Flashcards
(14 cards)
What filters at the glomerulus?
water, salts, glucose, urea
What does not filter at the glomerulus?
protein, blood cells,
What is reabsorbed in the proximal tubule?
100%: glucose, amino acids
90%: K, Ca, phosphate, bicarb, uric acid
66%: Na
passive: Cl, water, urea
How is urine concentrated in the loop of Henle?
- Descending limb and thin portion of the loop of Henle are freely permeable to water and salt
+ water flows out of the tubule, into the hyperosmotic interstitium
+ urine is concentrated: reduced volume, hypertonic - NaCl is actively reabsorbed into the thick ascending loop of Henle
+ segment is impermeable to water
+ urine becomes hypertonic as NaCl is pumped back into the medullary interstitium = urine volume is greatly reduced and is hypotonic
Where does ADH come from and act?
- synthesized by the hypothalamus and released from the posterior pituitary
- acts on the distal tubule and collecting ducts: increasing aquaporins and promoting reabsorption of water
Where does aldosterone come from and act?
- synthesized in the zona glomerulosa of adrenal cortex
- acts on late distal tubule and collecting duct to synthesize NaCl transporters
Where is the final regulation of water excretion and acid-base balance?
distal tubule and collecting ducts
Permeability of the distal tubule and collecting ducts to water is controlled by what?
ADH
Aldosterone stimulates _____ reabsorption in the ____________ and _________.
Na
late distal tubule
collecting ducts
Retention of ____ promotes water _______.
Na
reabsorption
___ is directly exchanged for Na.
K
Aldosterone promotes ___ loss.
K
Aldosterone is released in response to what 3 conditions?
Ang II / low blood pressure
hyponatremia
hyperkalemia
Aldosterone plays most important role in controlling ___ excretion and _____ _______.
Na
fluid volume
