20.Relative concentrations along proximal convoluted tubules Flashcards Preview

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Flashcards in 20.Relative concentrations along proximal convoluted tubules Deck (14):
1

(Tubularb fluid) / plasma ( smaller, bigger , equals 1)

TF/P bigger than 1 --> when solute is reabsorded less quickly than water
TF/P smaller than 1 --> when solute is reabsorded more quickly than water
TF/P = 1 --> when solute and water are reabsorbed at the same rate

2

substance with TF/P = 1

Na+

3

substance with TF/P smaller than 1 (explain ) (in order)

from more negative to 0
1. Glucose
2. Aminoacids
3. HCO3
solutes is reabsorded more quickly than water ---> concentration in plasma is bigger than tubule

4

substance with TF/P bigger than 1 (explain ) (in order)

from more positive to 0
1. PAH
2. Creatine
3. Inulin
4. Urea
5. Cl-
6. K+
water is reabsorded more quickly than solutes ---> concentration in tubule is biger than plasma

5

inulin (explain

TF/P bigger than 1 --> tubular inulin increases in concentration ( But not amount ) along the PCT) as a result of water reabsorption

6

Cl- ( explain

TF/P bigger than 1 --> Cl- rea bsorption occurs at a slower rate than Na+ in early PCT and then matches at the rate of Na+ reabsorption more distally --> thus its relative concentration increases before it platues

7

• Para-aminohippurate (PAH), unlike inulin, is pumped into renal tubules. Its tubular fluid/plasma ratio is ____ (higher/lower) than inulin's.

Higher (concentration of PAH increases because of both water reabsorption and active secretion into the tubule by the proximal tubule cells)

8

• The tubular fluid:plasma ratio for amino acids and glucose is less than that of inulin, suggesting net PCT ____ (reabsorption/secretion).

Reabsorption

9

• Reabsorption of which electrolyte drives water reabsorption, nearly matching total osmolarity throughout the length of the proximal tubule?

Sodium

10

• HCO3- concentration along the length of the proximal tubule decreases so it has net ____ (reabsorption/secretion/neither).

Reabsorption (HCO3- is reabsorbed more avidly than most other ions)

11

• In a mouse model, nephron inulin concentrations throughout the PCT are measured. Distally, they rise. Is this secretion?

No (inulin concentration increases as a result of water reabsorption [concentration], the raw amount is constant)

12

• Under what condition will the tubular fluid to plasma ratio (TF/P) of a solute be greater than 1?

When the solute is reabsorbed less quickly than is water

13

• Under what condition will the tubular fluid to plasma ratio (TF/P) of a solute be less than 1?

When the solute is reabsorbed more quickly than is water

14

• Under what condition will the tubular fluid to plasma ratio (TF/P) of a solute be equal to 1?

When the solute is reabsorbed at the same rate as water

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