reabsorption secretion Flashcards
GFR results in large quantities of ___ of plasma
ultrafiltrate
60% of reabsorption occurs in the __ ___
proximal tubule
sodium is ___ transported out of the proximal tubule fluid into blood
actively
glucose and amino acids are ___ transported out of the tubule fluid by means of ___ ____ mechanism
passively
sodium cotransport
Cl-, phosphate and bicarbonate ions ___ move into blood due to an imbalance of ___ charge
passively
electrical
movement of sodium and chloride into blood causes an ___ imbalance, moving water ___ into blood
osmotic
passively
about half of urea ____ moves out of tubule with the rest moving on to the ___ ___ ___
passively
loop of henle
urea is important in the __ mechanism and ___ of urine
countercurrent
concentration
reabsorption in the loop of henle
- water is reabsorbed from the tubule fluid
- urea is picked up from the interstitial fluid in the ___ limb
descending
reabsorption in the loop of henle
- sodium and chloride are reabsorbed from the filtrate in the ___ limb
- where the reabsorption of salt makes the tubule fluid dilute and creates and maintains a ____ osmotic pressure of the medulla’s interstitial fluid
ascending
high
proximal tubule urea goes ____; distal tubule urea ___ because of diffusion
out
in
diffusion
distal tubule reabsorbs sodium by ____ transport but in ___ amounts than the proximal tubule
active
smaller
ADH is secreted by the ___ ____ and targets cells in the distal tubule and collecting ducts to make them ___ permeable to water
posterior pituitary
more
with the reabsorption of water in the collecting duct, the urea concentration of the tubule fluid ___, causing urea to diffuse ___ of the collecting duct into the medullary interstitial fluid
increases
OUT
urea participates in a ___ multiple mechanism, that along with the countercurrent mechanisms of the loop of henle and vas recta, maintains the ___ osmotic pressure needed to form ___ urine and avoid ____
countercurrent
high
concentrated
dehydration
increase osmolarity –> ___ reabsorption of water
increase
reabsorption = ___ - ___
filtration - excretion
reabsorption of water and electrolytes
- 2 paths for reabsorption
- H20 by ____
paracellular; transcellular
osmosis
reabsorption = from the ___ ___ to the ___
tubular lumen
blood
___: movement of water to ___ concentration from ____ concentration
lesser
greater
primary active transport of Na+
- 2 paths
paracellular/transcellular
primary active transport of Na+
- ___ ___ pump
- potassium ___ to be ___
- once Na+ is in the interstitial fluid is is ___ into the capillary
sodium-potassium pump
in; secreted
diffused
secondary active transport
- 2 ways into the cell
- ____ - Na+ symporter with ____
- ____ - sodium exchanger with ___
SGLT - glucose
NHE - H+
secondary active transport -
- sodium is actively transported out by the ___ ___ pump
- glucose out by ____ (facilitative diffusion)
sodium-potassium
GLUT
___ ___: number of carriers in the renal tubules available to ferry each particular substances
transport maximum
once the transport maximum is reached for all nephrons, further ____ in tubular load are NOT reabsorbed and are excreted
increases
___: tubular load at which transport maximum is exceeded in some nephrons
threshold
4 examples of substances who have transport maxs
glucose
amino acids
phosphate
sulphate
sodium is brought in via a symporter with ____ and an antiport with ___
glucose
H+
water follows ___ by diffusion
Na+
as water is diffused, ___ concentration of urea, ___ osmolarity and urea is ___ by concentration gradient by diffusion
increase
increase
reabsorbed
from the cell to the interstitial space
- __ Na+ out
- __ K+ in
3
2
Na+ reabsorbed –> ___ lumen negative potential –> ___ Cl- reabsorption
increase
passive
Na+ reabsorption –> H20 ____ –> ___ luminal cl concentration –> ___ cl- reabsorption
follows
increase
passive
Na+ reabsorption –> H20 ____ –> ____ luminal urea concentration –> ___ urea reabsorption
follows
increase
passive
proximal tubule
- ___% of tubular reabsorption
- 7 substances reabsorbed
- 3 substances secreted
60
- Na+, Cl-, HCO3-, K+, H20, glucose, amino acids
- H+, organic acids, bases
THIN descending loop of henle very permeable to ____
water
THICK ascending loop of hence
- ___% of filtered load
- reabsorption of 6
- secretion of ___
- ___ permeable to water
- 25
- Na+, Cl-, K+, HCO3-, Ca2+, Mg2+
- H+
- NOT
NaCl and K+ transport in THICK ascending loop of henle
- symporter of ___ Na+, __ Cl-, ___ K+ into the cell
- K+ moves into the ___ ___ and the ____
- Cl- moves into the ___ ___
- Na+ passively diffused by the ___ ___ pump
1; 2; 1
interstitial fluid; lumen
interstitial fluid
sodium-potassium
loop ____ inhibit the symporter in the ascending loop of henle
diuretics
loop diuretics:
- prevents ___ in the looop of hence
- water will follow
- ___ more
- extracellular compartment ____
- cause ___ plasma volume
- ___ blood pressure
reabsorption urinate decrease low decrease
3 loop diuretics
furosemide
ethacrynic acid
bumetanide
early distal tubule
- sodium is symported with ___ from the lumen to the tubule cells
- sodium/potassium pump used to go from ___ to ___ ___
- ___ diffuses into the interstitial fluid
chlorine
cell –> interstitial fluid
chlorine
thiazide diuretics inhibits the symporter in the early ___ tubule
distal
early distal tubule
- functionally similar to ___ ___ loop
- ____ ___ to water
- active reabsorptioin of 4 things
- contains ___ ___ cells
thick ascending
no permeable
Na+, Cl-, K+, Mg++
macula densa
early distal tubule
- __% of filtered load
- not permeable to ___
- not very permeable to ____
5
water
urea
late distal tubule
- permeability to water depends on ___
- not very permeable to ____
ADH
urea
cortical osmolarity is ___, there for ___ urea is absorbed
low
less
medullary osmolarity is ____, therefore ____ urea is absorbed
high
more
___ helps maintain osmolaity in different parts
urea
late distal and cortial collecting tubules ___ cells secrete potassium
principle cells
principle cells
- ___/___ ___ brings in the Na+ and K+
- leads to passive diffusion of ___ out of the cell into the interstial fluid, ___ into the lumen, and ___ into the cell
sodium potassium pump
Cl-
K+
Na+
aldosterone antagonists like spironolactone and eplerenone inhibit the ___ ___ ___ in the principal cells
sodium postassium pump
aldosterone antogonists compete for ___ with aldosterone
receptors
Na+ channel blockers like amiloride or triamterene blocks the diffusion of Na+ from the ___ to the ___
lumen
cell
late distal and cortical collecting tubules ___ cells secrete H+
intercalated
intercalated cells
- exchange H+ with ___ using active transport
- H+ exported using ___ transport
- Na+/K+ pump
- ___ and ___ diffused out of the cell
Cl-
K+
