Renal Control of Acid-Base Balance

Question 1

What is considered “volitile” and requiring to be breathed off?

Answer 1

Glc (aerobic)

Fat

Question 2

What is considered to be “fixed” and can be neutralized at the kidneys?

Answer 2

Glc (anaerobic) –> lactate
Cys –> sulfate
Phosphoprotein –> PO4-

Question 3

A change in pH of _____ causes a _____ or _____ in [H+]

Answer 3

0.3

Doubles or halves

Question 4

4 body buffer systems

Answer 4

Bicarb
Hb
PO4-
Plasma proteins

Question 5

Buffering of EC H+ w/ K+
If acidic:
If alkaline:

Answer 5

Acidic: ICF takes H+ and donates K+.
Alkaline: ICF takes a K+ and donates a H+.

Question 6

Henderson-Hasselbach equation

Answer 6

pH = 6.1 + log([A-]/[HA])

Question 7

How to determine [HA]?

Answer 7

0.03 x partial pressure CO2

Question 8

Renal reabsorption of HCO3- along the nephron

Answer 8

85% at PT
10% at TAL
4.9% at CD

Question 9

How does HCO3- and H+ enter the cell?

Answer 9

Via 2 CA reactions to create CO2 and H2O. They diffuse into the cell and undergo the same reactions to create HCO3- and H+ again. HCO3- is reabsorbed across the BL membrane and H+ is recycled back into the lumen.

Question 10

What transporters are in the luminal membrane of the PT? (2)

Answer 10

NHE (Na in, H out)

H+ ATPase

Question 11

What transporters are in the basolateral membrane of the PT? (3)

Answer 11

Na/K ATPase
Na+-HCO3- symporter
HCO3- Cl- antiporter

Question 12

What 2 main things can cause increased H+ secretion?

Answer 12

Decreased plasma [HCO3-]

Increased partial pressure of CO2.

Question 13

How does phosphate buffering work?

Answer 13

NaHPO4- accepts an H+ and is excreted.

Question 14

What is the luminal transporter involved in phosphate buffering?

Answer 14

NHE (Na in and H out)

Question 15

What is the source of NH3 in the kidney?

Answer 15

Glutamine, which is in endless supply at the kidney.

Question 16

How does NH3 increase H+ secretion?

Answer 16

NH3 is transported via NaKCC2 (in place of K) and is trapped in CD. H+ pumped out and adds to NH3 and is secreted.

Question 17

a-cells (HCO3-, H+)

Answer 17

Reabsorb HCO3-

Secrete H+

Question 18

B-cells (HCO3-, H+)

Answer 18

Reabsorb H+

Secrete HCO3-

Question 19

NAE must equal =

Answer 19

Nonvolitile production to maintain A-B balance

Question 20

Titratable acids

Answer 20

Phosphate salts (1/3)

Question 21

NH4+ in NAE

Answer 21

Its secretion and synthesis is equal to 2/3

Question 22

High anion gap metabolic acidosis causes

Answer 22

MeOH
Uremia
DKA
Paraldehyde
Isoniazid
Lactic acidosis
EtOH
Renal failure
Salicylates

Question 23

Non-anion gap metabolic acidosis causes

Answer 23

Hyperalimentation
Acetazolamide
Renal tubular acidosis
Diarrhea
UPS
Post-hypocapnea
Spironolactone

Question 24

RTA 1

Answer 24

Distal tubules
Acidotic
Hypokalemia
a-cells don’t secrete H+

Question 25

RTA 2

Answer 25

Proximal tubules
Acidotic (less than RTA 1)
Hypokalemia
Failed HCO3- reabsorption in PT

Question 26

RTA 4

Answer 26

Adrenal
Mildly acidotic
Deficiency in aldosterone

Question 27

Sx of mild metabolic acidosis

Answer 27

Usually asymptomatic

Question 28

If pH < 7.10 sx

Answer 28

Nausea, vomiting, fatigue.

Notice deep breathes w/o dyspnea.

Question 29

Causes of metabolic alkalosis

Answer 29

Contraction
Licorice
Endo
Vomiting
Excess alkali
Refeeding alkalosis
Post-hypercapnea
Diuretics

Question 30

Overall, what causes metabolic alkalosis? (3)

Answer 30

Loss of H+
Gain of HCO3-
Loop or thiazide diuretics

Question 31

Sx of severe metabolic alkalosis

Answer 31

Headache
NM problems
Lethargy
Seizures
Decreased threshold for cardiac problems

Question 32

What is the cause for the metabolic alkalosis symptomology?

Answer 32

Increased Ca binding of albumin –> decreased Ca levels –> hypocalcemia

Question 33

Causes of acute respiratory acidosis

Answer 33

CNS problems
Airway obstruction
NM problems
Severe PE, pneumonia

Question 34

Causes of chronic respiratory acidosis

Answer 34

COPD

Question 35

Causes of respiratory alkalosis

Answer 35

CNS dz
Hypoxia
Anxiety
Mechanical ventilators
Progesterone
Salicylates/sepsis

Question 36

Acute respiratory alkalosis sx

Answer 36

Light-headedness, confusion, cramps.
TACHYPNEA.
Carpopedal spasm due to decreased Ca levels.

Question 37

What is the compensation of metabolic acidosis?

Answer 37

Hyperventilation

Increase HCO3- regenration and H+ secretion

Question 38

What is the compensation of metabolic alkalosis?

Answer 38

Hypoventilation

Decreased HCO3- regeneration and H+ secretion

Question 39

What is the compensation of respiratory acidosis?

Answer 39

Increase H+ excretion and HCO3- regeneration

Question 40

What is the compensation of respiratory alkalosis?

Answer 40

Decrease H+ excretion and HCO3- regeneration