Flashcards in Renal Phys--> Connecting segment and Collecting duct Deck (17):
Which two types of cells are found in the Collecting segment and collecting duct?
What is another name for this area?
Aldosterone sensitive distal nephron
What is the principle's cell main role?
Absorb Na and Cl resorption
What the primary role of the intercalated cell?
H+ and HCO3- excretion
Some K resorption
What the regulatory channels in this area?
Aqueporin 2 (AQP2)
At this point what should have all been removed from filtrate?
All glucose, AA's and Bicarb
10% of water left
What is the Na resorption here? Significance?
- First area that is directly controlled to determine urinary electrolyte conc.
What affect does aldosterone have on the principle cell?
Lipophillic so passes through lipid bilayer easily
- binds to SRE (Steroid response element)
- Increases number and Activity of ENAC
- Increased sodium resorption
- Caveat= more K+ excreted
What then is the stimulus for Aldosterone release?
What else can act like aldosterone? When is it seen?
Prednisone--> why you get puffy on steroids
What is little syndrome?
- leads to increase ENAC
- K wasting
What percent of Na is controlled by aldosterone?
What does the sympathetic NS control?
Stimulates Na uptatke in proximal tubule
a. increase Na-K-ATPase
b. Increase Na-H+ anti-porter
Controls afferent and efferent tone
- thus reduces RPF and GFR
What are 3 signaling pathways which stimulate renin release?
1. Sympathetic input
2. Decrease stretch of afferent arteriole
3. Decrease Cl delivery to to Macula Densa
What are the actions of AgII?
2. Stimulate prox tubule to increase Na resorption and increases ENAC
3. Salt appetite via CNS
4. Stimulates aldosterone
5. Increase sympathetic activity
What does the macula densa sense?
-Regulate Renin release and GFR