Loop of Henle, Distal Tubule, Collecting Duct Flashcards Preview

CRRAB II > Loop of Henle, Distal Tubule, Collecting Duct > Flashcards

Flashcards in Loop of Henle, Distal Tubule, Collecting Duct Deck (29):
1

% of filtered Na reabsorbed in the Loop of Henle?

25%

2

Descending loop is permeable only to:

Water (reabsorbed)

3

Osmolality of filtrate as it passes through descending, deep medullary, and ascending loop:

300 mOsms

1400 mOsm

100 mOsm

4

Which segment of loop is not permeable to water?

Ascending

5

Membrane apparatus carrying solutes from collecting tubule lumen into cell in the Thick Ascending Limb?

NKCC pump

6

What is the driving force of the NKCC pump?

Na

7

What is the limiting factor in the NKCC pump?

Cl

8

% of the filtered Na reabsorbed in the Thick Ascending Loop?

20%

9

Type of diuretic that acts on NKCC pump?

lasix (furosemide)

10

% of filtered Na reabsorbed in the Distal Tubule?

5%

11

Is distal tuble permeable to water?

no

12

Pump of action in the distal tubule?

Na/Cl symporter....secondary active transport driven by Na

13

Genetic mutation of NaCl pump in distal tubule?

Gitleman Syndrome

14

5 key features of Gitleman Syndrome:

1. Normal BP

2. Metabolic alkalosis

3. hypocalciuria

4. hypomagnesemia

5. hypokalemia

15

Drugs that manipulate NaCl channel in distal tubule?

thiazide diuretics

16

First area with VARIABLE reabsorption of Na?

Collecting duct

0-5%

17

Two principle channel types in Principal cells of collecting tubules?

ENac's (epithelial Na channels)

ROMK's (renal outer medullary K channels)

18

Collecting duct permeability to water?

Variable

19

Primary mechanism of controlling salt reabsorption in principle cells?

Aldosterone

**regulated by RAAS

20

3 primary signals stimulating renin release?

1. SNS--NE

2. Decreased stretch in afferent arterioles

3. Decreased Cl delivery to macula densa

21

Where is renin released from?

Juxtaglomerular cells in the afferent arteriole

22

Clinical triggers for renin release:

1. hypovolemia

2. low Na diet

3. low body NaCl

4. high SNS activity

23

4 primary actions of Angiotensin II:

1. stimulates aldosterone

2. systemic vasoconstriction

3. stimulates proximal tubule reabsorption of Na

4. Increases SNS activity

24

Why can aldosterone cross freely into cells?

lipophilic

25

What cell does aldosterone act on and what does it do there?

Principal cells of the collecting duct

-increases transcription of ENaCs, ROMKs, and Na-K-ATPase (basolateral membrane)

26

What does ROMK do?

Secretes K into collecting duct

27

% of filtered Na controlled by aldosterone:

2%

28

Little's syndrome?

can't shut off ENaCs --> increases BP

29

Type I pseudohypoaldosteronism?

loss of ENaC function