Flashcards in 20.Relative concentrations along proximal convoluted tubules Deck (14):
(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
substance with TF/P = 1
substance with TF/P smaller than 1 (explain ) (in order)
from more negative to 0
solutes is reabsorded more quickly than water ---> concentration in plasma is bigger than tubule
substance with TF/P bigger than 1 (explain ) (in order)
from more positive to 0
water is reabsorded more quickly than solutes ---> concentration in tubule is biger than plasma
TF/P bigger than 1 --> tubular inulin increases in concentration ( But not amount ) along the PCT) as a result of water reabsorption
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
• 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)
• The tubular fluid:plasma ratio for amino acids and glucose is less than that of inulin, suggesting net PCT ____ (reabsorption/secretion).
• Reabsorption of which electrolyte drives water reabsorption, nearly matching total osmolarity throughout the length of the proximal tubule?
• 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)
• 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)
• 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
• 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