Renal Physl 18 Flashcards

1
Q

What takes care of the majority of pH disturbances?

A

Buffer systems and ventilation

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

What are the two ways kidneys can alter pH?

A
  • Reabsorption or excretion of H+

* Modifying HCO3- reabsorption or excretion

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

How is H+ affected by the kidneys during acidosis?

A

The kidneys secrete H+ into tubule lumen

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

What are buffers in the kidneys?

A

Ammonia from amino acids, and phosphate ions (HPO4 2-)

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

What are large amounts of hydrogen ions trapped as in the kidneys?

A

NH4+ and H2PO4- which is excreted

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

What do the buffers in the kidneys help with?

A

Excretion of H+ excretion by binding to them in the lumen

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

What do the kidneys generate during the excretion of H+ ions?

A

Bicarbonate ions from carbon dioxide and water

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

What can the carbon dioxide and water produced in the kidney do?

A

Go into the bloodstream and act as a buffer and help increase pH

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

What happens in the kidneys during alkalosis?

A

HCO3- is secreted and H+ is reabsorbed to help restore pH

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

How long do renal response to acidosis or alkalosis take?

A

24-48 hours

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

What does the apical Na+-H exchanger do?

A

Brings sodium into the cell and H+ into the lumen against its concentration gradient

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

What does the Basolateral Na+- HCO3- symporter do?

A

Moves Na+ and HCO3- out of the cell and into the interstitium. Using the energy from bicarbonate moving down its concentration gradient

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

What does H+ ATPase (proton pump) do?

A

Pumps H+ into the lumen of distal nephron against its concentration gradient

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

What does the H+ K+ ATPase do?

A

Pumps H+ into urine in exchange for K+ and can contribute to potassium homeostasis

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

What does the Na+ NH4+ antiporter do?

A

Puts NH4+ into the lumen in exchange for Na+

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

What part of the nephron plays an important role in hydrogen secretion and bicarbonate reabsorption?

A

The proximal tubule

17
Q

What happens to most of the bicarbonate that is filtered by the kidneys?

A

It is reabsorbed to maintain the body’s buffer systems

18
Q

Which tubule reabsorbs most bicarbonate?

A

The proximal tubule

19
Q

What two ways does the proximal tubule reabsorb bicarbonate?

A
  • Filtered bicarbonate is converted into carbon dioxide which is then converted back into bicarbonate for reabsorption
  • Using the amino acid glutamine
20
Q

Why does the proximal tubule need to reabsorb bicarbonate indirectly?

A

Because there is no apical membrane transporter

21
Q

How is filtered bicarbonate is converted into carbon dioxide which is then converted back into bicarbonate for reabsorption?

A
  • Hydrogen is secreted from the proximal tubule epithelial cell into the lumen opposite of sodium which is pumped into the cell using the Apical Na+-H+ exchanger (NHE)
  • Carbonic anhydrase bound to the apical membrane combines the secreted hydrogen with filtered carbonate to form carbon dioxide in the lumen
  • The carbon dioxide then diffuses from the lumen into the tubule cell
  • Within the cell carbon dioxides combines with water to form carbonic acid which dissociates to hydrogen and bicarbonate
  • The bicarbonate can be transported out of the cell using the Na+ HCO3- symporter which put it into the interstitium
22
Q

What is the process for bicarbonate reabsorption and H+ excretion using amino acid metabolism?

A
  • Glutamine in the proximal tubule cell is metabolized to alpha ketoglutarate and NH4+ (ammonium ion)
  • Ammonium is transported into the lumen in exchange for sodium and is excreted
  • Alpha ketoglutarate is further metabolized to form bicarbonate which is transported into the blood along with sodium
23
Q

What is acid base balance closely regulated by in the distal nephron?

A

Intercalated cells

24
Q

What type of cells are the target of aldosterones actions?

A

Principle cells

25
What do intercalated cells have a high level of?
Carbonic anhydrase so they can rapidly convert carbon dioxide and water into hydrogen ions and bicarbonate
26
What does the intercalated cells do to the H+ they produce?
They are pumped out of the cells by the hydrogen ATPase or the hydrogen potassium ATPase
27
What does the intercalated cells use to move the bicarbonate they produce?
It enters the interstitium by the bicarbonate chloride antiporter
28
What do Type A intercalated cells do during acidosis?
Secrete hydrogen ions and reabsorb bicarbonate
29
What do type B intercalated cells do during alkalosis?
Secrete bicarbonate and reabsorb H+ ions
30
What is different for how type A intercalated cells secrete H+ during acidosis vs the proximal tubule?
The apical hydrogen ATPase and hydrogen potassium ATPase is used rather than the sodium hydrogen antiporter
31
How do type B intercalated cells reabsorb H+ during alkalosis?
They reabsorb hydrogen ions by transport into the interstitium on the basolateral side of the cell while bicarbonate is secreted into the lumen