Sodium and water transport along the nephron Flashcards Preview

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Flashcards in Sodium and water transport along the nephron Deck (54)
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1

How many moles of sodium are filtered in the Bowman's capsule a day?

2500 mmoles

2

How many moles of sodium are excreted a day?

150 mmol

3

How many litres of blood are filtered a day?

180 L

4

How many litres of urine are produced a day?

1.5 L

5

What happens to the sodium and water that are not excreted?

Reabsorbed in the tubules

6

What are the sites of reabsorption in the tubule?

PCT -> PST -> DTLLH -> TALLH -> DCT -> Collecting duct

7

What reabsorption happens in the PCT?

50% water and 50% sodium is reabsorbed Isotonic

8

What reabsorption happens in the PST?

20% water and 20% sodium Isotonic

9

What reabsorption happens in the DTLLH?

5% water

10

What reabsorption happens in the ATLLH?

20% sodium

11

What reabsorption happens in the DCT?

5% sodium

12

What reabsorption happens in the collecting duct?

4% sodium 19% water

13

In which parts of the tubule is reabsorption isotonic?

PCT and PST

14

Which parts of the tubule are impermeable to water?

TALLH and DCT

15

What separates the lumen and interstitial fluid in a renal epithelial cell?

Tight junction

16

What controls most reabsorption in the renal epithelial cells?

Sodium movement

17

What controls movement of sodium in and out of renal epithelial cells?

Sodium potassium pump

18

What does the lumen refer to?

The tubule

19

What does the interstitial milieu refer to?

The blood

20

What substances are reabsorbed in the PCT along with sodium?

Glucose Amino acids Phosphate Chlorine Protons Water

21

What type of transporters control the movement of these molecules along with sodium?

Most are symporters Protons - sodium - proton antiporter Chlorine - channel Water - aquaporins

22

What feature makes cells permeable to water?

Presence of aquaporins

23

What is the role of the TDLLH in controlling salt and water reabsorption?

Mainly control equilibration of sodium and water via channels and aquaporins

24

Is the process of reabsorption in the TALLH active?

Yes - requires lots of ATP

25

What type of cotransporter is uniquely present on epithelial cells of the TALLH?

2-chloride, potassium, sodium cotransporter

26

What does the potassium transporter on TALLH epithelial cells do?

Recycle potassium

27

Why is a positive transepithelial potential created in TALLH epithelial cells?

Chlorine is transported into the blood - 2 chlorines for every sodium Transporting more chlorine ions than sodium = positive transepithelial potential

28

What does this positive transepithelial potential do?

Transports additional chlorine, sodium, potassium and calcium through a paracellular shunt

29

Which cells of the collecting duct regulate water and sodium reabsorption?

ENaC - epithelial sodium channel ROMK - Renal Outer Medullary Potassium Channel

30

Is water and sodium permeability regulated in collecting duct epithelial cells?

Yes