Renal diluting segments and collecting systems Flashcards

(30 cards)

1
Q

Where on the nephron is water permeable?

A

Proximal tubule
Descending Loop of Henle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where on the nephron is water impermeable?

A

Ascending thin loop of Henle
Thick ascending loop of Henle
Early part of distal convoluted tubule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where is permeability to water regulated by ADH?

A

late part of distal convoluted tubule
Collecting tubule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What aquaporin channel is found in the proximal tubule and descending loop of Henle?

A

AQP1
AQP7 - straight PT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What aquaporin channel is found in the late distal convoluted tubule and collecting tubule?

A

Constitutive AQP3 and AQP4 on basolateral
Facultative AQP2 on apical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where is NaCl reabsorbed?

A

Thin and thick ascending limb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the conc of fluid leaving TAL compared to plasma?

A

Dilute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the driving force for transcellular transport in the TAL?

A

Basolateral Na+K+ATPase pump - maintains low intracellular Na+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What mediates Na+ movement across apical membrane of the TAL?

A

NKCC2 symporter (also expressed by macula densa cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is essential for continued operation of NKCC2 symporter in the TAL?

A

K+ channels on apical membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What else mediates Na+ movement across apical membrane of TAL?

A

Na+-H+ antiporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What other channels are present on the basolateral membrane of TAL?

A

Na+-HCO3- symporter
Cl- channels
K+Cl- channel
K= channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What drives paracellular reabsorption in the TAL?

A

Lumen-positive potential driven by K+ channels on apical membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What cations does the TAL reabsorb?

A

Na+, K+, Mg2+ and Ca2+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do loop diuretics work?

A

Increase volume of excreted urine by blocking Na+ reabsorption at specific sites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What loop diuretics block NKCC2?

A

Furosemide
Bumetanide

17
Q

What maintains the low intracellular Na+ in the early DCT?

A

Na+-K+-ATPase pump

18
Q

What mediates entry of NaCl across apical membrane in early DCT?

A

Na+-Cl- symporter

19
Q

How does Cl- leave the cell in early DCT?

A

Via Cl- channels on basolateral membrane

20
Q

What 2 cells are found in the late DCT and collecting ducts?

A

Principal and intercalated cells

21
Q

What is the MoA of principal cells?

A

Reabsorb Na+. Cl- and water
Secrete K+
Dependent on Na+-K+-ATPase pump on basolateral membrane

22
Q

What is the MoA of intercalated cells?

A

Reabsorb K+
Secrete H+ or HCO3-
Dependent on apical H+-K+ATPase pump

23
Q

What channels absorb Na+ on the apical membrane of the late DCT and collecting duct?

A

ENaC channels

24
Q

What is transported paracellularly in the late DCT and collecting ducts?

25
What regions of the kidney and low water permeability without ADH?
Outer medullary and cortical regions
26
What triggers ADH production?
Hyper osmosis
27
What does ADH bind to in the late DCT and collecting ducts?
V2 receptor on basolateral membrane
28
What does the V2 receptor activate?
cAMP
29
Where is the AQP2 water channel expressed?
Apical membrane of late DCT and collecting ducts
30
How is water absorbed into the blood?
By osmosis via constitutively AQPs on basolateral membrane