Acid-Base Physiology

Question 1

What range of pH can the body tolerate?

Answer 1

6.8-7.8

Question 2

What is the normal plasma bicarbonate concentration?

Answer 2

24 mEq/L

Question 3

What is the equation for the bicarbonate buffer system?

Answer 3

CO2 + H2O H2CO3 H+ + HCO3-

Question 4

What is the formula for calculating hydrogen concentration?

Answer 4

[H+] = 24 PCO2/[HCO3-]

Question 5

Bicarbonate decrease causes…

Answer 5

Metabolic acidosis

Question 6

Bicarbonate increase causes…

Answer 6

Metabolic alkalosis

Question 7

Decreased CO2 causes…

Answer 7

Respiratory alkalosis

Question 8

Increased CO2 causes…

Answer 8

Respiratory acidosis

Question 9

How does the body compensate for respiratory disorders besides adjusting lung activity?

Answer 9

Bicarbonate concentration 1-2 days

Question 10

HCO3 levels always change with…

Answer 10

PCO2

Question 11

What are some causes of metabolic acidosis?

Answer 11

Decreased acid excretion; direct bicarb loss from GI/urine; increased acid generation; renal failure leading to inability to excrete acid as NH4+

Question 12

What is the most common cause of chronic respiratory acidosis?

Answer 12

COPD

Question 13

What are some causes of metabolic alkalosis?

Answer 13

Loss of H through GI (vomiting) or urine (diuretics)

Excessive urinary net acid excretion

Question 14

What is the primary disturbance in metabolic acidosis?

Answer 14

HCO3- depleted to buffer extra acid

Question 15

What is the respiratoy compensation for metabolic acidosis?

Answer 15

Hyperventilation

Question 16

What is the kidney compensation for metabolic acidosis?

Answer 16

Increase H+ excretion as NH4+

Increase reabsorb/production of HCO3-

Question 17

What is the formula for the serum anion gap?

Answer 17

[Na] - [Cl] - [HCO3-] = anion gap

Question 18

What are the unmeasured anions that the serum anion gap is measuring?

Answer 18

Phosphate
Citrate
Sulfate
PROTEIN

Question 19

When does the serum anion gap increase in metabolic acidosis?

Answer 19

When concentration of an unmeasured anion increases to help replace HCO3-

Question 20

When is the serum anion gap normal in metabolic acidosis?

Answer 20

When the concentration of Cl- is what compensates for HCO3-

Question 21

What is the primary disturbance in metabolic alkalosis?

Answer 21

HCO3- increases in response to a decrease in H+

Question 22

What is the respiratory compensation for metabolic alkalosis?

Answer 22

Hypoventilation

Question 23

How does the kidney respond to metabolic alkalosis?

Answer 23

Increase HCO3- excretion because the excess filtered load is above ability to reabsorb

Question 24

What is the primary disturbance in respiratory acidosis?

Answer 24

Increased arterial PCO2, which through mass action is converted to H+ and HCO3-

Question 25

What is the renal compensation for respiratory acidosis?

Answer 25

Increase H+ excretion as NH4+; increase reabsorption of HCO3-

Question 26

What is the primary disturbance in respiratory alkalosis?

Answer 26

Decreased arterial PCO2 due to hyperventilation, which causes decreased H+ and HCO3-

Question 27

What is the renal compensation for respiratory alkalosis?

Answer 27

Decreased H+ excretion and increased reabsorption of new HCO3-

Question 28

Does the plasma anion gap change in respiratory acid-base disorders?

Answer 28

No

Question 29

Alpha cells do what to change acid base balance

Answer 29

Use active transport to eliminate H into urine. The H is generated from HCO3- in interstitium by CA.

Question 30

What is the urinary anion gap?

Answer 30

Na + K - Cl