Brainscape's Knowledge GenomeTM

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


See full index

Renal Physiology > Reabsorption/Secretion in the Proximal Tubule > Flashcards

Reabsorption/Secretion in the Proximal Tubule Flashcards

1
Q

How many times is the entire plasma filtered through the glomerulus every day?

A

60 times, equivalent to 5 times for whole body fluid

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

What percentage of reabsorption of glomerular filtrate is absorbed through the proximal tubule?

A

2/3rd

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

What is the primary role of the proximal tubule?

A

reabsorbtion of most of the filtered water and solutes

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

What is the gold standard for mesasuring GFR?

A

Inulin

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

Why is inulin the gold standard for measuring GFR?

A

It is neither reabsorbed or secreted in the tubules.

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

Is reabsorption in the proximal tubule is iso-osmotic?

A

yes

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

what are the major solutes that contribute to the isotonic reabsorption in the proximal tubule?

A

sodium, choride, bicarbonate

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

Does the concetration of inulin decrease or increase compared to the distance from the glomerulus?

A

increase

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

What absorption requires the most amount of energy?

A

sodium, using active transport, accounting for the majority of oxygen consumption in the kidney

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

where does sodium reabsorption occur?

A

throughout the entire nephron,

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

Is the concentration of sodium high or low in the tubular lumen, tubular epithelial cells and the renal interstitium?

A

high in tubular lumen
low in the tubular epithelial cells
high in the renal interstitium

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

In the tubular epithelial cell, where is the only place the na/k atpase pump located?

A

on the basolateral membrane, near the renal interstitium

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

what are the two results and overall purpose of the nka pump?

A
  1. decrease the intracellular sodium conc.
  2. decreased membrane potential

allows for the driving force for na absorption

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

why does sodium flow through the apical membrane without energy?

A

it’s flowing down it’s electrochemical gradient

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

the passive diffusion of sodium down it’s electrochemical gradient allows for what?

A

a passive, coupled transport of other solutes from the renal epithelial cell into the lumen for reabsorption. either through antiport or cotransport

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

what is the only quantitatively important substance whose transport is directly coupled to metabolic energy in proximal tubule?

A

sodium, all others are secondarily related.

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

what solutes are related to metabolic energy through secondary means?

A

bicarbonate, glucose, amino acids, organic acids

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

Na reabsorption is coupled with an equivalent movement of what to allow ofor electroneutrality?

A

anions

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

What drives the movement of chlorine out of the tubule?

A

the rapid na reabsorption leaves the lumen with a -5mv charge. This charge this pushes the chlorine into the renal interstitium.

20
Q

Explain the general idea behind a leaky epithelium of the proximal tubule.

A

it favors anion transport via paracellular space. leaky in the context of allowing more anions to move on purpose…

21
Q

In the straight proximal tubule, how does the absorption of chlorine change?

A

chlorine absorption is reduced.

22
Q

what is absorbed more rapidly within the straight proximal tubule than chlorine?

A

hco3-, outcompetes the chlorine

23
Q

What drives water reabsorption?

A

the osmotic gradient, facilitated by the lekay epithelium with high hydraulic conductivity (high kf value).

24
Q

What does massive solute reabsorption lead to in terms of osmolarity?

A

slight decrease in osmo of tubular luminal fluid and increase in interstitial fluids

25
Q

what is the name of the type of corce that is involved in capillary uptake of fluid from the interstitium?

A

starling forces

26
Q

what are starling forces?

A

acoss the peritubular capillary endothelium that drives rapid uptake of fluid from the interstitial compartment

27
Q

what three pressures allow for uptake of fluid into the capillaries from the interstitial spaces? aka peritubular factors

A

positive interstitial fluid pressure
low hydrostatic pressure in peritubular capillaries
high oncotic pressure in peritubular capillaries

28
Q

In the proximal tubule, absorption of mculs is iso-osmotic but it is selective?

A

yes, not all mculs are absorbed to the same extent

29
Q

Is bicarbonate preferred in over chlorine for absorption in proximal tubule?

A

yes

30
Q

where is H+ actively secreted into?

A

pt, dt, cd

31
Q

how is proton secretion regulate in pt?

A

at the apical membrane, na-h exchanger (driven by na gradient)

on the basolateral membrane, hco3 is secreted into interstitial space, through the hco3-na cotransporter

32
Q

how is glucose reabsorbed?

A

it is through a cotransporter na-glucose

33
Q

what are the names of the two na glucose co transporters?

A

sglt1 sglt2

34
Q

what is the threshold level for glucose?

A

200-220 mg/dl

35
Q

what is the transport maximum?

A

where secretion rate d.n change.

compared to threshold, which is when you’re going to start seeing gluocse in the urine.

36
Q

what does glucosuria cause?

A

thirst and nocturia (due to osmotic diuresis)

37
Q

what are the causes of glucosuria?

A

pregnancy
diabetes mellitus
renal glucosuria (mut in sglt1 and sglt2)

38
Q

what is amino acid reabsorption coupled to

A

soidum

39
Q

where is the sodium-amino acid transport located on the epithelial cells?

A

apical membrane

40
Q

what three conditions have high protein excretion?

A

multiple sclerosis
hemoglobinemia
myoglobinemia

41
Q

in what condition will you have excessive excretion of organic acids?

A

diabetic ketoacidosis

42
Q

is phosphate never excreted or continuously excreted in the urine? why?

A

continuously, because the threshold for phosphate is very low

43
Q

what are the two reasons chlorine is passivley absorbed?

A

concentration gradient created by water reabsorptino

electrochemical potential gradient created by sodium reabsorption

44
Q

what are the absorption characteristics of diuretics?

A

they are freely filtered and not reabsorbed, can increase osmolarity and cause diuresis

45
Q

what is mannitol

A

a diuretic, not produced or metabolized in the body, no transporters for mannitol

Renal Physiology (26 decks)

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