Renal Test Flashcards

1
Q

Where is 98% of the Potassium in the body?

Why?

A

Intracellular

creates charge potential

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

What is normal Potassium concentration?

A

4 mEq/L

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

An increase in K+ ______ excitability.

A

Increases

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

Hyperkalemia _______ resting membrane potential, which ______ excitability.

A

Decreases

Increases

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

What happens to Potassium immediately after ingestion in the GI tract?

A

Na/K ATPas rapidly takes up

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

What 3 hormonal factors are involved in the GI uptake of Potassium?

A

Epinepherine

Insulin

Aldosterone

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

What role do kidneys play in regulation of body Potassium?

A

Excretion when K+ ECF too high

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

Where is filtered load of Potassium reabsorbed along the nephron?

A

90% Proximal tubule and Ascending limb

10% Delivered to distal nephron

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

How is Potassium excretion primarily regulated?

A

By controlling the rate of Secretion

*from capillaries into the collecting tubule

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

Potassium excretion primarily regulated by ______

Na and Water excretion primarily regulated by ________

A

Secretion

Reabsorption

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

How is it that a greater % of potassium is excreted than delivered to the distal nephron?

A

Secretion from Interstitium into late Distal Tubule and Collecting Tubule

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

What are 2 ways the Distal Nephron can compensate for Hypokalemia?

A

Secretion stops

Reabsorption

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

Where does Reabsorption occur in case of Hypokalemia?

Luminal/Basolateral channels?

A

Distal nephron

Luminal: via K+/H+ antiporter
Basolateral: K+ selective

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

In normal Potassium Secretion/Reabsorption, what channels are crossed Luminally and Basolaterally

(1 luminal, 2 basolateral)

A

Luminal: Na/K ATPase

Basolateral: K+ channels and K+/Cl- cotransporters

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

How does an increase in Distal Na+ reabsorption affect Potassium secretion?

How?

A

Increases

By creating Lumen Negative potential

(pushes K+ back into distal nephron)

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

A decrease in ECF H+ (alkalosis) will _____ plasma K+

An increase in ECF H+ (acidosis) will _______ plasma K+

A

Decrease

Increase

*this occurs to maintain charge balance

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

T/F

Inorganic acids have a much greater effect on K+ than organic acids

A

True

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

T/F

Respiratory acidosis has little to no effect on Plasma K+

A

True

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

Does increase in ECF K+ concentration affect acid base status?

A

No?? It appears K is cleared in the kidneys through Secretion

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

What 2 things affect the rate of Potassium Secretion?

A

Plasma potassium

Tubular fluid flow rate

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

An increase in ECF (plasma) K+ concentration will increase Secretion/Excretion in what 2 ways?

A

Increases Na/K ATPase activity in Distal Nephrons

Increase Aldosterone secretion

*Ald has 2 effects

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

How does Aldosterone secretion increase K+ excretion (by secretion)?
2 things

A

Na/K ATPase activity

Luminal membrane permeability

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

In what 2 ways does an increase in tubular fluid flow increase K+ secretion?

A

Minimizes tubular fluid concentration

Increases Na+ reabsorption (which increases Na/K ATPase, increasing intracellular K+)

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

Extended use of loop diuretics leads to…

A

Hypokalemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
In what 2 ways does the use of loop diuretics increase K+ excretion? (leading to hypokalemia)
Decreases K reabsorption in thick ascending limb Increases secretion (by increasing tubular fluid flow and increasing distal Na absorption) *and Na reabsorption drives K excretion by increasing Na/K ATPase and increases intracellular K
26
Why doesn't ADH increase K excretion even though it increases tubular fluid flow?
Resorbs water do distal nephron unaffected ??
27
Name 3 organs and 1 hormone that affect plasma Calcium levels.
Kidney, G-Intestinal, Bone PTH
28
What are the 3 functions of the kidney in maintaining Calcium levels?
Vitamin D activation Renal Calcium excretion/reabsorption (distal tubule) Renal Orthophosphate excretion/reabsorption (HPO4 -2)
29
What does PTH do to phosphate? Where? Mechanism?
Decreases reabsorption (increasing excretion) Proximal Tubule Inhibits Na/phosphate co-trnasporter on luminal membrane
30
How does PTH stimulate Calcium reabsorption in the Distal Tubule? 2 things
Ca ATPase Na/Ca exchanger basolateral membrane
31
What is a volatile acid?
15-20,000 mmol/day CO2 *oxidative metabolism
32
Why are volatile acids usually of no concern?
Exhaled
33
What is a "Fixed" non-volatile acid? 2 things that create?
50 mmol/day inorganic/organic Exercise, Diabetes (ketoacidosis)
34
Name 3 ways the body prevents major shifts in pH when there is constant generation of metabolic acids.
Bicarb CO2 respiration Renal compensation (H+ excretion, bicarb production)
35
What is the point of maximum buffering capacity?
pKa
36
T/F | Bicarb has dual control. The lungs regulate CO2. Kidneys regulate plasma concentration of bicarb.
True
37
What converts H2CO3 to water and carbon dioxide?
Carbonic Anhydrase
38
What is the typical value of plasma bicarb?
24 mmol/L
39
What is thy typical value of plasma CO2?
1.2 mmol/L
40
What ratio in the Henderson Hasselbach equation will result in a pH of 7.4?
20:1
41
The Henderson-Hasselbalch equation helps predict pH by evaluating what?
Acid/Base ratio CO2/bicarb
42
When CO2 diffuses into the RBC, it is converted to...
H+ and bicarb (HCO3-)
43
How does bicarb diffuse out of the lungs (after its trasformation from CO2)?
Exchanges with Cl-
44
T/F | The H+ left over in the RBC is buffered by de-oxygenated Hb.
True
45
T/F | H+ preferentially binds to de-oxygenated Hb
True
46
What 2 factors principally regulate respiration rate?
CO2 levels Plasma H+ concentration
47
What is the contribution of the Kidneys in the extreme case of HCl? 2 things
New bicarb generation H+ excretion
48
More than 99% of filtered bicarb is reabsorbed where?
Proximal tubule
49
The reabsorptive process of bicarb in the Proximal Tubule is _____
Indirect
50
What is the mechanism of the Indirect bicarb reabsorption that occurs in the Proximal tubule
Carbonic Anhydrase forms bicarb Intracellularly, exports H+ to lumen, where bicarb + H+ > water and CO2 IC bicarb exits through basolateral membrane to ECF *this is 1:1
51
What is the rate-limiting step in the reabsorption of bicarb in the Proximal tubule?
H+ ATPase
52
Where is bicarbonate generated in the nephron? 2 places/processes
Distal Intercalated collecting tubule cells (titratable acids) Proximal tubule (Glutamine metabolism)
53
Generation of new bicarb in distal collecting tubule from titratable acids is dependent on the availability of what?
Urinary buffers *rate limiting step
54
What is metabolized in the proximal tubule to generate bicarb? What is co-generated?
Glutamine Ammonium
55
Why is it essential to have additional tubular buffers (like titratable acid and NH3) other than bicarb?
Quick depletion
56
The source of renal NH3 is...
NH4 from Glutamine production
57
How can acid-base status affect NH3 synthesis?
Metabolic acidosis increases Glutamine metabolism Increases NH4 increases NH3+ **increases bicarb synth
58
What are the 3 primary factors regulating H+ secretion?
Intracellular generation of H+ (water + CO2 via carbonic anhydrase = bicarb + H+) H/Na antiporter (luminal, proximal tubule) H+ ATPase (luminal, intercalated collecting tubule)
59
Where does Aldosterone affect the regulation of bicarb?
Intercalated collecting tubule cells
60
How does Aldosterone affect the regulation of bicarb?
increases H+ ATPase which increases H+ secretion which increases HCO3 reabsorption
61
What are the 4 simple acid base disorders
Metabolic/Respiratory Acidosis/Alkalosis
62
How does the kidney compensate for Respiratory acidosis/alkalosis?
changes bicarb levels *slow response
63
T/F | A change in respiration rate can adjust CO2 levels in cases of Metabolic acidosis/alkalosis
True
64
The renal response for a change in pH due to Metabolic disturbances is what? 2 things
Resorb all filtered bicarb Generate new bicarb
65
What is the proper acid base homeostatic level?
7.4
66
To compensate for metabolic acidosis, the kidney resorbs and synthesized new bicarb. If pCO2 is low so there's no H+ secretion, how does the body compensate?
Hypoventilation
67
What is an Anion Gap?
Means of identifying cause of metabolic acidosis
68
If acidosis is from an organic acid, there is a _____ in gap, If acidosis is from an inorganic acid, there is _____ in gap
Change No change