Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

FHB Renal > Week 7, lecture 1 > Flashcards

Week 7, lecture 1 Flashcards

(61 cards)

Start Studying
1
Q

About what total % is the filtrate reabsorbed at the PT?

A

2/3

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

What is iso-osmotic reabsorption? What is it in terms of a ratio?
What is reabsorbed iso-osmotically at the PT?

A
  • Water reabsorption occurs in = proportion w/reabsorbed solutes
  • tubular conc : plasma conc osmolality ratio of 1.0
  • Na+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the only thing reabsorbed at the PT with a [TF]/[P]x100 ratio greater than 100?
What % of it is reabsorbed at the PT?

A
  • Cl-

- 60%

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

What % of Na+ is reabsorbed at the PT?

A

67% (H2O follows)

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

What % of Pi is reabsorbed at the PT?

A

70%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What % of HCO3- is reabsorbed at the PT?

A

80%

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

What other 3 things are reabsorbed at a rate of ~90% at the PT?

A

Glucose, lactate, and amino acids

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

What is the tubular lumen potential (RMP) at the PT?

Why is it what it is?

A

-4mV

Because there are leaky tight junctions

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

What does a value > 100 of [TF]/[P]x100 indicate?

A

> 100 = relatively less of the solute vs. H2O reabsorbed

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

In the first 1/2 of the PT, what is Na+ reabsorbed w/ (secondary active symport)?

A

HCO3-, PO43-, glucose, amino acids, lactate

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

Name all of the transporters found on the apical side of the first 1/2 of the PT.

A
  • Na+ taken up passively
  • Na+/H+ antiporter (secondary)
  • Na+/glucose symporter (secondary; along w/Na/X xporters?)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What creates the gradient for apical Na+ coupled xport in the first 1/2 of the PT?
Which side of the cell is it on?

A
  • Na-K pump

- Basolateral side

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

Once symported into the apical side of the cell w/Na+, how do HCO3-, PO43-, glucose, amino acids, and lactate get across the basolateral side of the first 1/2 of the PT?

A

Facilitated diffusion, mostly

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

What causes the RMP in the first 1/2 of the PT?
How did it get into the cell?
How does it get out of the cell?

A

K+

  • Got in thru NKP
  • Gets out thru passive diffusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the ratios of ion movement with the Na/HCO3- symporter in the first 1/2 of the PT?
How else are HCO3- ions moved out of the basolateral membrane?

A

1x Na+ - 3x HCo3- symporter

Cl- HCO3- antiporter

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

W/ what is Na+ reabsorbed w/in the 2nd half of the PT, primarily?

A

Cl-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Thru what general pw’s is Na+ reabsorbed in the 2nd half of the PT?
What % reabsorption occurs thru each?
What other thing is reabsorbed here via these 2 methods?

A

Transcellularly (67%) and paracellularly (33%)

- Cl-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

In the 2nd half of the PT, what 2 ways do Na+ and Cl- cross the apical membrane to be reabsorbed?
What can form, and how does the process continue?

A

Parallel Na+-H+ and Cl–anion antiporters
- H+Anion complexes can form in tubular fluid that can recycle across the apical membrane to bring in more Na+ and Cl- (anions are secreted into urine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

In the previous example of Na+ and Cl- antiport across the apical membrane w/ an anion, what forms can the anion take?

A

OH- (hydroxide), HCO2- (formate), oxalate, HCO3-, sulfate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What enzyme is found in the FIRST half of the PT that involves one of the things we’ve talked about?
What does it do?

A

Carbonic anhydrase (CA), creating bicarb from CO2 and H2O, this increasing acidity via H+ production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the transepithelial potential at the 2nd 1/2 of the PT? What is the potential in the blood?
What generates this transepithelial potential??

A

+4mV (lumen is -4mV; blood is 0)

- Generated by the diffusion of Cl- (lumen to blood) across the tight junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What provides the driving force for the diffusion of Cl- into the cell at the 2nd half of the PT?

A

High [Cl-] in the tubular fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How is glucose reabsorption in the 2nd half of the PT different from the first 1/2?

A

Still Na+/glucose symport, but now 2x Na+ required per glucose, still facilitated diffusion to leave the basolateral side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Would you find an NKP on the basolateral side of the 2nd half of the PT?
What other transporter involving K+ would you find there?

A
  • Yes

- K+ Cl- symporter (both out, using K+ gradient from NKP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How is water concentration related to osmolality?
Increased [H2O], decreased osmolality (and vice versa)
26
Can H2O follow Na+ transcellularly, paracellular, or both?
Both
27
Besides Na+, what other things can H2O follow to be reabsorbed in the PT?
Cl-, organic solutes
28
Explain solute (solvent?) drag.
H2O highly concentrated in ISF; its hydrostatic pressure pushes H2O into caps, and solutes/ions follow (especially K+ and Ca2+)
29
Normally, what % of proteins are reabsorbed at the PT?
100%
30
What is the main method by which proteins are reabsorbed at the PT? What is the other method?
- Pinocytosis | - Can also get enzymatic degradation to AA's
31
Are organic ions secreted into the PT? | Why is this dangerous w/r/t drug toxicity?
Yes | - They compete for the same carriers (e.g. cimetidine and procainamide)
32
If there was a urine/plasma osmolality ratio > 1 in the distal loop/DT, what would it indicate w/r/t [ADH] and urine color?
High [ADH] | Concentrated, dark urine
33
If there was a urine/plasma osmolality ratio
Low ADH | Dilute, pale urine
34
About what total % is the filtrate reabsorbed at the distal loop/DT?
1/3
35
In the distal loop/DT, what is the lumen potential? Why?
-40mV (non-leaky tight junctions)
36
What is the major process that occurs in the descending limb of the loop (and what is impermeable)?
- H2O reabsorption (Na+ and Cl- impermeable)
37
What is the major process that occurs in the thin ascending limb of the loop (and what is impermeable)?
- Passive Na+ and Cl- reabsorption (H2O impermeable)
38
What is the major process that occurs in the thick ascending limb of the loop (and what is impermeable)?
- Na+ and other constituents reabsorbed (H2O impermeable)
39
What % of Na+, K+, Cl- (...) are reabsorbed at the thick ascending loop of Henle?
25%
40
In the thick ascending limb of the loop of Henle, what 2 major (and 1 minor) transporters/channels would you find on the apical side?
- Na+ H+ antiporter (H+ secreted; secondary) - 1x Na+ 1x K+ 2x Cl- symporter (secondary) - Minor leak channels of K+
41
In the thick ascending limb of the loop of Henle, what things can undergo transcellular diffusion into the blood?
Na+, K+, Ca2+, Mg2+
42
What enzyme is present in the cells in the thick ascending limb of the loop of Henle and why?
CA, creates H+ ions that leave via the apical Na+ H+ antiporter (bicarb leaves somehow)
43
Explain the action of furosemide in the thick ascending limb of the loop of Henle. What is the else result?
- Blocks the Na/K/Cl symporter (so the 25% of reabsorption of these things no longer occurs, passed on to rest of nephron). This overwhelms downstream reabsorption, H2O flow is increased due to increased salt in the urine --> diuresis
44
What transporters/etc are found on the basolateral side of the thick ascending limb of the loop?
- Cl-/K+ symporters (into blood using Cl- gradient) | - NKP (every cell of body has it)
45
In the early DT, what transporter types would you find on the apical side?
Na+ Cl- symporter (only) | - Would also get some passive Cl- diffusion
46
In the early DT, what transporter types would you find on the basolateral side?
- NKP | - Cl- channels for passive diffusion
47
What % of Na+ is processed by the late DT/collecting duct?
8% (100 - 67 - 25)
48
Regarding the late DT/collecting duct: | What is the pH of the urine? Blood? How much of a difference in [H+] is this?
4. 4 in the urine, 7.4 in the blood | - 1000x more in the urine (has strong pumps and urine can't leak out thru tight junctions)
49
What transporters/etc would you find on the basolateral side of cells in the late DCT/collecting duct?
- NKP - K+ diffusion channels - HCO3- diffusion channels (I think)
50
What transporters/etc would you find on the apical side of cells in the late DCT/collecting duct?
- Na+ channels (Na+ flows in passively) - K+ channels (K+ flows out passively) - H+ pump (uses ATP to just pump H+ out) - K+/H+ pump (uses ATP to pump K+ in, H+ out)
51
What other enzyme friend is found in the late DCT/collecting duct?
CA, doing its thing
52
Is there any net secretion of H+ in the PCT?
No, it all occurs at the DCT/collecting duct
53
What is the tubular lumen potential at the late DCT/collecting duct?
-40mV
54
What part of the nephron does ang II act on? | What is the final action of it?
- PT | - Increased Na+, Cl-, and H2O reabsorption
55
What stimulates aldosterone production? What parts of the nephron does aldosterone act on? What is the final action of it?
- Increased ang II or increased plasma [K+] - Thick ascending loop of Henle, DCT, collecting duct - Increased reabsorption of Na+ and Cl- (the "salt hormone")
56
What stimulates ANP production? | What are the final actions of it?
- Swollen atria due to ^ ECV/HTN | - Increased natriuresis; decreased TPR; decreased reabsorption of Na+ and Cl-; decreased ADH
57
What is sympathetic stimulation responding to, in regards to the nephron? What part of the nephron does it act on? What does it stimulate?
- Responds to low ECV - Distal and proximal nephron - Increased reabsorption of Na+ and Cl-
58
What is ADH responding to, in regards to the nephron? What part of the nephron does it act on? What does it stimulate?
- Decreased ECV or increased plasma osmolality - Collecting duct - Reabsorption of H2O (w/o affecting salts, therefore it is the "water hormone"). (note: also does urea reabsorption)
59
What are Starling forces?
Forces across the cap wall of the PCT that govern solute and water reabsorption (hydrostatic and oncotic forces)
60
What is glomerulotubular balance (GT balance)?
- Despite variations in GFR, a constant fraction of Na+ and water and still reabsorbed from the PCT (67%)
61
Recall: what is tubuloglomerular feedback (TG feedback)?
1. ^ GFR 2. ^ [NaCl] in tubular fluid 3. Signal generated by MD cells of JGA 4. ^ resistance of afferent arteriole

FHB Renal (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions