Lecture 34 Unit 5 Flashcards

1
Q

what is the relationship between tubular fluid and blood at the end of the PCT

A

isotonic

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2
Q

what is the relationship between tubular fluid and blood at the end of the loop of henle

A

hypotonic to blood

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3
Q

what is the relationship between tubular fluid and blood at the renal corpuscle

A

isotonic to blood

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4
Q

what does most reabsorption

A

PCT

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5
Q

what does the rest of the nephron besides the PCT do

A
  • solutes reabsorbed by active and passive processes
  • water follows solutes by osmosis
  • small proteins move across into the blood by pinocytosis
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6
Q

what does tubular secretion do

A

transfers materials fr9m blood into tubular fluid

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7
Q

what happens in tubular secretion

A
  • controls blood pH through secretion of H+

- helps eliminate certain substances

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8
Q

what happens in paracellular reabsorption

A

-50% of reabsorbed material moves between cells by diffusion in some parts of tubule

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9
Q

what happens in transcellular reabsorption

A

material moves through both the apical and basal membranes of the tubule cell by active transport

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10
Q

how is Na+ reabsorbed

A

Na+/K+ ATPase pumps sodium from tubule cell cytosol through the basolateral membrane

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11
Q

what is obligatory water reabsorption

A

when water is obliged to follow the solutes being reabsorbed

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12
Q

what is facultative water reabsorption

A

occurs in collecting duct under the control of ADH

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13
Q

what helps reabsorb materials from filtrate in PCT

A

Na+ symporters

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14
Q

how are intracellular sodium levels kept low

A

Na+/K+ pumps on the basolateral side

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15
Q

what is glycosuria

A

some glucose remains in the urine

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16
Q

what happens if blood glucose levels exceed 200 mg/ml

A

renal symporters cannot reabsorb glucose fast enough

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17
Q

what happens in diabetes mellitus

A

insulin activity is deficient and blood glucose cannot enter cells as readily

18
Q

what is the renal threshold for glucose

A

200 mg/mL

19
Q

how does the loop of henle reabsorb ions

A

Na+/K+/2Cl- symporters

20
Q

how does K+ move into filtrate in the loop of henle

A

K+ leak channels

21
Q

how is Na+ reabsorbed in loop of henle

A

Na+ is pumped out on basolateral side

22
Q

how is Cl- reasbroed in loop of henle

A

diffusion

23
Q

how do cations move to vasa recta

A

passively

24
Q

what is thick ascending limb impermeable to

A

water

25
Q

is early DCT permeable to water

A

yes

26
Q

are Na+ and Cl- reabsorbed by different symporters than loop of henle

A

yes

27
Q

all water reabsorption until late DCT is what?

A

obligatory

28
Q

what are the cells in the late DCT

A

principal cells and intercalated cells

29
Q

what do principal cells do

A

reabsorb na+ and secrete k+

30
Q

what do intercalated cells do

A

reabsorb K+ and HCO3- and secrete H+

31
Q

what would happen without ADH

A

late DCT and CD are impermeable to water

32
Q

throughout journey through nephron what happens to tubular fluid

A

volume is decreasing

33
Q

what is goal of producing dilute urine

A

remove excess fluid from blood

34
Q

what is the concentration if blood plasma

A

300 mOsm/L

35
Q

what happens to filtrate osmolarity as it moves down loop of henle

A

increases

36
Q

what happens to filtrate osmolarity as it moves up loop of henle

A

decreases

37
Q

what happens to filtrate osmolarity is CD

A

decreases so it produced dilute urine

38
Q

what is the goal of concentrated urine

A

prevent water loss by excreting only concentrated urine

39
Q

what happens as the concentration of ADH increases

A

more aquaporin channels are inserted into apical membranes of principal cells

40
Q

water reabsorption in late DCT and CD is what?

A

optional -facultative reabsorption

41
Q

what are the ADH actions leading to concentrated urine

A
  • stimualtes Na+/K+/Cl- symporters in thick limb of ascending loop of henle
  • stimulates facultative water reabsorption in upper and lower CD
  • stimulates urea recycling in lower CD