Renal Phys--> Connecting segment and Collecting duct Flashcards Preview

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Flashcards in Renal Phys--> Connecting segment and Collecting duct Deck (17):
1

Which two types of cells are found in the Collecting segment and collecting duct?

Principle cell
Intercalated cell

2

What is another name for this area?

Aldosterone sensitive distal nephron

3

What is the principle's cell main role?

Absorb Na and Cl resorption
K excretion

4

What the primary role of the intercalated cell?

H+ and HCO3- excretion
Some K resorption

5

What the regulatory channels in this area?

ENAC
ROMK
Aqueporin 2 (AQP2)

6

At this point what should have all been removed from filtrate?

All glucose, AA's and Bicarb
10% of water left

7

What is the Na resorption here? Significance?

Variable 0-4.99%
- First area that is directly controlled to determine urinary electrolyte conc.

8

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

9

What then is the stimulus for Aldosterone release?

Low Na
High K+

10

What else can act like aldosterone? When is it seen?

Cortisol
Prednisone--> why you get puffy on steroids

11

What is little syndrome?

Pseudohyperaldosteronism
- leads to increase ENAC
- HTN
- K wasting

12

What percent of Na is controlled by aldosterone?

2%

13

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

14

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

15

What are the actions of AgII?

1. vasoconstrict
2. Stimulate prox tubule to increase Na resorption and increases ENAC
3. Salt appetite via CNS
4. Stimulates aldosterone
5. Increase sympathetic activity

16

What does the macula densa sense?

-Flow
-Cl-
-Regulate Renin release and GFR
-Tonically active

17

What does decreased Cl- to macula densa cause?

Means decrease GFR or decrease sodium
- Prostaglandin release
- Renin release triggers RAAS