Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Renal-1 > Renal Transport Mechanisms > Flashcards

Renal Transport Mechanisms Flashcards

1
Q

What are the 5 barriers a substance must cross to be absorbed? (transepithelial transport)

A

leave tubular fluid –> through cell of tubular epithelium –> basolateral membrane –> interstitial fluid –> through capillary wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where are glucose and AAs reabsorbed?

How much?

A

100% reabsorbed in proximal convoluted tubule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What places is sodium reabsorbed?

A 
65-70% in PCT
25% in thick ascending limb of LoH
5% DCT
3% collecting duct
<1% bladder
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is reabsorbed in the PCT?

A 
CHAMPSPUG
calcium = 70%
H2O = 70%
Amino acids = 100%
magnesium = 30%
potassium = 70%
sodium = 70%
phosphate = 70%
urea = 50%
glucose = 100%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What things are absorbed 70% in the PCT?

A 
SPPCH
sodium
phosphate
potassium
calcium
H2O
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How much Urea is reabsorbed in the PCT? What about other places?

A

50% reabsorbed in PCT

variable amts in DCT, collecting duct, and bladder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In general, what does the PCT reabsorb?

A

67% of filtered water and solutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the key element in PCT reabsorption?

A

Na/K ATPase pump in the basolateral membrane

reabsorption of every substance is linked in some way to it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is special about PCT reabsorption in regard to water?

A

PCT is freely permeable to water
solutes filtered –> osmosis occurs
isosmotic reabsorption = solutes and water absorbed at same rate = 300 mOsm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does the Na/K ATPase pump help transport Na?

A

pump pushes 3 Na out to interstitial fluid –> lowers intracellular Na –> Na from tubule comes into cell down its gradient via sodium ion leak channels
overall = net movement from lumen to IF (and eventually back to blood)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is transcellular transport?

What is paracellular route?

A

through the cells

in between cells (limited bc tight junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does the sodium/hydrogen exchanger do?

A

found on apical membrane of PCT

pull in one sodium ion into the cell in exchange for moving one H+ out into the lumen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is chloride reabsorbed?

A

more water than Cl- reabsorbed in first half of PCT –> Cl concentration rises in tubular fluid as it goes on –> provides concentration gradient –> passively goes back to blood via paracellular mvnt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of transport does chloride use?

A

paracellular mvnt is the main way

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where does water move paracellularly?

A

paracellular = thin descending LoH bc few tight jxns

in thick ascending LoH, way more tight jxns, so won’t go paracellularly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where is aquaporin-1 present?

A

in the PCT

17
Q

Where is aquaporin-2 present?

A

in collecting duct (under control of ADH)

18
Q

Where is water absorbed throughout the nephron?

A

PCT = 67% (passive through aquaporins)
LoH - 15% (in descending only, via paracellular and aquaporins)
Early Distal tubule = 0%
late distal tubule and collecting duct = 8-17% (via aquaporins)

19
Q

Where do ADH, ANP, and BNP regulate water reabsorption?

A

in late distal tubule and collecting duct via aquaporin II

20
Q

What glucose transporters are located in the proximal PCT?

How much glucose do they reabsorb?

A

SGLT2 and GLUT2 = high capacity, low affinity

90%

21
Q

What glucose transporters are located in the distal PCT?

how much glucose do they reabsorb?

A

SGLT1 and GLUT1 = low capacity, high affinity

10%

22
Q

What is the “novel approach to type 2 diabetes treatment” mentioned?

A

inhibiting renal SGLT2 –> reduces blood glucose levels by decreasing glucose reabsorption –> just pee it out

23
Q

What is TmG?

A

transport maximum for glucose = 375 mg/min
SGLT1 and 2 will absorb filtrate glucose until all receptor sites are full –> anything above Tm is not reabsorbed and escapes into the urine

24
Q

What occurs in the thin descending loop of henle?

A

H2O permeable –> absorption of 25% of filtered H2O
impermeable to solutes
water leaves behind solutes –> increasing concentration in tubular fluid = increased osmolarity

25
Q

What occurs in the thick ascending loop of henle?

A

35-40% of filtered NaCl resorbed here

in contrast to descending limb, solute reabsorbed w/out water

26
Q

How does the countercurrent multiplier work in the LoH?

A

water only reabsorbed in descending –> super concentrated lumen fluid at the bottom –> solutes only reabsorbed in ascending –> gets less concentrated at the top

27
Q

How do loop diuretics (furosemide) work?

A

inhibit sodium chloride reabsorption by competing for the Cl- binding site on the carrier

28
Q

What is reabsorbed in theDCT?

A

sodium = 5%
calcium = 8%
magnesium = 8%
H2O and urea variable

29
Q

Where is the NKCC transporter found?

What does it do?

A

found in thick ascending LoH

takes 1 Na, 1 K, and 2Cl from lumen into endothelial cells

30
Q

What 5 transporters are utilized in the thick ascending LoH?

A

NKCC –> into lumen cells
apical K+ channel –> K back into lumen
Na/K ATPase –> 2K into cell from IF, 3Na to IF
Cl- channel –> into IF/blood
basal K+ channel –> K into IF down its gradient

31
Q

What type of transporter is the Na/Cl cotransporter, and where is it?

A

symporter
located in DCT
pulls in both Na and Cl from the lumen into the DCT cells

32
Q

When is aldosterone released, and what cells does it act upon?

A

released from adrenal cortex in response to angiotensin II or directly in response to increased plasma K+ –> acts on collecting ducts and DCT –> increased Na resorption and more secretion of excess K+

33
Q

How does Na reabsorb in the late DCT and collecting duct?

A

Na channel (alpha, beta, etc)

34
Q

How does sodium cross the apical membrane in the PCT?

A 
Na-H andtiporter
Na-glucose symporter (SLGT2)
Na-symporter w/ AAs
Cl/base antiporter
paracellular
35
Q

How does K+ sparing spironolactone work?

A

inhibits Na+/K+ exchange in distal tubule and collecting duct –> promotes K+ retention and Na+ and water loss through urine = hypotensive effect

36
Q

How does ADH work?

A

makes distal and collecting tubules more permeable to water –> medullary osmotic gradient can act upon more dilute tubular fluid –> reabsorb more water

37
Q

What happens if you drink a lot of water and need to lose the excess H2O without losing solutes?

A

Dont have any ADH secreted –> 20% of filtered fluid that reaches the distal tubule is not reabsorbed bc impermeable to water –> excretion of wastes remains constant –> dilute urine

Renal-1 (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions