Lecture 3: Definition of Tubular Processes (Bolser) Flashcards Preview

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Flashcards in Lecture 3: Definition of Tubular Processes (Bolser) Deck (16):
1

define filtration

process by which water and solutes in the blood leave the vascular system thru filtration barrier and enter Bowman's capsule

2

define secretion

process by which moving substances into the tubular lumen from the cytosol of epithelial cells that form the walls of the nephron

3

define reabsorption

the process of moving substances from the lumen across the epithelial layer into the surrounding interstitium.

4

define excretion

exit of the substance from the body

5

tubular transport maximum (Tm)

the maximum amount of a substance that can be reabsorbed or secreted by tubules.

6

what is the excretion rate formula? (it determines the amount excreted)

excretion rate (mg/min) = U x V
U = concentration in urine
V = urine flow rate

7

what is the formula for filtered load? (it determines the amount filtered)

filtered load (mg/min) = P x GFR
P = concentration in plasma

8

what is excretion equal to?

the filtration for a substance that is neither secreted nor reabsorbed. Inulin is the perfect example of this substance

9

what substance is filtered and neither secreted nor reabsorbed?

inulin

10

if a substance
amount excreted < amount filtered
then what happened to that substance?

then it has been reabsorbed

11

what are examples of reabsorbed substances?

water, Na, Cl, HCO3, K, organic solutes (like sugars, amino acids, etc)

12

what is the formula for the amount reabsorbed?

amount reabsorbed = amount filtered - amount excreted

13

if a substance
amount excreted > amount filtered
then what happened to that substance?

then the substance has been secreted

14

what is the formula for the amount secreted?

amount secreted = amount excreted - amount filtered

15

what are examples of secreted substances?

K, H, NH3, organic acids and bases (like uric acid, PAH, drugs, etc)

16

what is splay?

it is a manifestation of the fact that nephrons have a range of tubular maximum. some nephrons have lower tubular maximums than the average and they will start leaking substances into urine earlier than other nephrons.

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