Concentration/Dilution (lec 12) Flashcards Preview

Q3 Physio II Test 2 > Concentration/Dilution (lec 12) > Flashcards

Flashcards in Concentration/Dilution (lec 12) Deck (36)
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1
Q

Normal urine is what-tonic?

Its normal osmolarity is?

A

hypertonic

285-295

2
Q

Kidney response to HYPOsmotic body fluid?

A

excretes dilute urine (water diuresis)

hyposmotic = water excess

3
Q

Kidney response to HYPERosmotic fluid?

A

excretes concentrated urine (antidiuresis)

hyperosmotic = water deficit

4
Q

Kidney’s ability to regulate water excretion is dependent or independent of solute excretion?

A

independent

5
Q

NaCl transport in descending LOH?

A

no active transport,

highly permeable to H2O

6
Q

NaCl transport in ascending LOH?

A

active transport of NaCl back to blood (reab),

impermeable to water

7
Q

Osmotic gradient in interstitial space (cortex to medulla) has what relationship with urine in collecting ducts?

A

it removes H2O from urine

8
Q

As fluid flows down descending LOH, what happens to the concentration?

A

becomes more [ ]

water is pulled from fluid

9
Q

As fluid flows up descending LOH, what happens to the concentration?

A

becomes diluted

NaCl is pulled from fluid

10
Q

Largest osmotic gradient possible across ascending LOH?

A

200

11
Q

Back diffusion = ?

A

active ion transport out of lumen

12
Q

Countercurrent Multiplier does?

A

creates large overall gradient from LOH (corticomedulla border to tip of papilla)

13
Q

Beginning osmolarity of fluid as enters Descending LOH?

A

300

14
Q

Countercurrent Multiplier: Thick Ascending Limb of LOH

NaCl transport mechanism?

A

Na+/K+/2Cl− cotransporter pulls NaCl from lumen into tubule cell

K+/Cl- cotrans and Na+/K+ pump move NaCl into medulla ISF

Ascending limb IMPERMEABLE to H2O, H2O can’t follow Na+

15
Q

Countercurrent Multiplier: Thick Ascending Limb of LOH

NaCl transport results in?

A

ISF osmolarity ↑ to 400,

ascending limb osmolarity ↓ to 200

16
Q

Countercurrent Multiplier: Descending Limb of LOH

H2O transport mechanism?

A

Fluid entering descending limb has 300 Osm,

ISF is now 400 Osm (from ascending transport of NaCl),

H2O pulled from lumen into ISF

17
Q

Coutercurrent Multiplier: Descending Limb of LOH

H2O transport results in?

A

descending limb osmolarity ↑ and is pushed down the limb,

fluid Osm keeps ↑ as it approaches distal turn of tube

18
Q

Main drive of the countercurrent multiplier is?

A

active transport

19
Q

Vasa Recta is?

A

capillary that follows inside the LOH hairpin turn

20
Q

Vasa Recta purpose?

A

preserve the ISF gradient created by LOH

21
Q

Vasa Recta: Descending Loop mechanism?

A

passive diffusion of NaCl in and H2O out

22
Q

Vasa Recta: Ascending Loop mechanism?

A

passive diffusion of H2O out and NaCl in

23
Q

Urea is made by?

A

hepatic protein catabolism

24
Q

Urea is recycled where in the kidney?

A

medulla

25
Q

Urea recycling is ↑ by?

A

ADH

26
Q

AHD affects Urea permeability how/where?

A

↑ urea permeability in the INNER medullary collecting ducts

27
Q

Early DCT: NaCl transportation mechanism?

A

NaCl cotransport and Na+ channel
from lumen into cell

Na+/K+ pump and Cl- channel
move NaCl into ISF

28
Q

Early DCT: NaCl cotransport blocked by what?

A

thiazide diuretics

29
Q

Early DCT: Impermeable to what?

Results in?

A

H2O

continued dilution of tubular fluid,
fluid remains HYPOsmotic

30
Q

Late DCT: Na+ and K+ transport mechanisms

Basolateral membrane?

A

Na+/K+ATPase -> Na+ reabsorption/K+ secretion

31
Q

Late DCT: Na+ and K+ transport mechanisms

Apical membrane?

A

Na+ and K+ channels

32
Q

Late DCT: Principle cells purpose?

Controlled by?

A

reab Na+/secrete K+

Aldosterone

33
Q

Late DCT: Aldosterone affects Principle Cells how?

A

↑ # of apical Na+ channels,

↑ Na+/K+ATPase

34
Q

Late DCT: ⍺-Intercalated cells purpose?

Mechanism?

A

secrete H+/reab K+ (balance pH)

H+ATPase
H+/K+ATPase

35
Q

Collecting Duct (CD): Permeable to?

ONLY in presence of?

A

H2O, Urea

ADH (vasopressin)

36
Q

Collecting Duct: ADH mechanism to cause H2O permeability?

A

ADH binds baso memb of DCT or CD cells ->
activates cAMP ->
↑ aquaporins (water channels) in apical membrane