Phys 1533 Renal Tubular Transport

Front 1

Define tubular reabsorbtion? Substances that use this route?

Back 1

movement of material from the tubular lumen to the peritubular capillaries. valuable molecules like glucose

Front 2

Define tubular secretion? Substances that use this route?

Back 2

PTC to the tubular lumen. Waste, toxins

Front 3

Define excretion?

Back 3

loss from body in urine

Front 4

What is filtered load?

Back 4

amount of material in glomerular filtrate

Front 5

define excretion rate?

Back 5

amount of material lost in urine

Front 6

Define fractional excretion.
if <1?
if >1?

Back 6

fraction of filtered mass that gets excreted.

FE=ER\FL

<1=some was reabsorbed
>1=some was added by secretion

Front 7

What are the routes of reabsorbtion in the kidney?

Back 7

Paracellular
Transcellular

Front 8

What 2 borders are crossed via transcellular absorbtion?

Back 8

apical(luminal) membrane and basolateral membrane, interstitial fluid and cap. wall are fast

Front 9

What ion are the secondary transport solutes dependent on?

Back 9

Na

Front 10

Give examples of solutes that use secondary transport mechanisms?

Back 10

Glucose, AA, lactate, citrate, PO4

Front 11

What 2 hormones are responsible for regulating the reabsorbtion of Na and H2o in the distal and collecting tubule?

Back 11

Aldosterone=Na reabsorbtion
ADH= water reabsorbtion

Front 12

HOw is water reabsorbed at the proximal tubule?

Back 12

Na is trasported across basolateral membrane by Na\K ATPase and water passively follows

Front 13

How is Na reabsorbed across the apical surface of the proximal tubule?

Back 13

Cotransport with organics(glc, AA's) and H+\Na antiport

Front 14

How is Cl- reabsorbed from the proximal tubule?

Back 14

paracellular and K\Cl cotransport

Front 15

How is Na reabsorbed across the basolateral membrane of proximal tubule cell?

Back 15

Na\K AtPase
Na\HCO3 cotransport

Front 16

What does angiotensin II stimulate in the proximal tubule?

Back 16

Na-H exchange at apical membrane so increases Na reab and H secretion

Front 17

What are the 3 signalling molecules\mechanisms that have and effect of the proximal tubules reabsorbtion of Na?

Back 17

Angiotensin II, Sympathetic nervous system, Parathyroid hormone

Front 18

What effect does sympathetic innervation have on proximal tubule reabsorbtion of Na?

Back 18

increases Na reabsorbtion

Front 19

How does parathyroid hormone affect Na reabsorbtion of at the Proximal tubule?

Back 19

inhibits Na-phosphate cotransport

Front 20

What is used as a marker for calculating the Tubular Fluid\Plasma concentration ratio?

Back 20

Inulin

Tf\Pinu=ratio of inulin filtered relative to water

Front 21

Define tubular Maxima? Where are Tm's primarily found?

Back 21

The maximal rate at which a solute can be reabsorbed. Proximal tubule

Front 22

What is a Threshold and what does it depend on?

Back 22

The min [plasma] before glucose is in urine. Depends on GFR

Front 23

What is the phenomenon of splay?

Back 23

Not all nephrons have the same Tm

Front 24

What is osmotic diuresis? examples

Back 24

When excess unreabsorbed solute in the tubular system of nephrons pulls Na and water back into the lumen from basolateral spaces.
diabetic glucosuria
high FL of urea
can be induced with mannitol(not reabsorbed)

Front 25

What are the 2 main transport mechanisms for for tubular secretion? Compounds secreted?

Back 25

organic anion tspt
organic cation tspt
metabolites and wastes(tagged by the liver)

Front 26

Give mechanism of organic anion tubular secretion? Limitation?

Back 26

Tertiary active transport
Na\K Atpase gradient used to bring alpha KG into the cell which is then used to countertransport OA into cell.
All organic anions compete for the same transporter

Front 27

How is the organic anion secretion mechanism used clinically?

Back 27

an organic anion (PAH) can be used to out compete theraputic drug secretion to prolong its action