6A - Respiratory Regulation of pH / Basic Acid-Base Disturbances

Question 1

6a3. What is a strong acid?

Answer 1

An H+ donor that dissociates completely in solution

Question 2

6a3. What is a weak base?

Answer 2

A H+ acceptor that does not dissociate completely (the dissociation is reversible)

Question 3

6a4. What are the equations for pH and the Henderson-Hasselbalch equation?

Answer 3

pH = -log[H+]

pH = pKa + log[HCO3]/[CO2]

Question 4

6a6. What are buffers?

Answer 4

Substances that prevent changes in pH. They accomplish this by binding H+ whenever the pH of the extracellular fluid drops below normal and they release H+ when the pH rises.

Question 5

6a6. What are the three major chemical buffer systems in the body?

Answer 5

1. Carbonic acid (H2CO) - Bicarbonate (HCO3)
2. Phosphate - HPO + H H2PO4
3. Protein (hemoglobin, albumins)

Question 6

6a6. What is the carbonic acid buffer system chemical equation?

Answer 6

CO2 + H2O H2CO3 H + HCO3

Question 7

6a8. What is the relationship between concentration of extracellular fluid CO2 levels and pH?

Answer 7

Any increase in CO2 concentration will decrease pH (via formation of H2CO3)

Question 8

6a8. Hypoventilation
- Increase or decrease CO2 levels in body?
- Increase or decrease pH?

Answer 8

Increases CO2 in the body

Decrease pH

Question 9

6a9. Hyperventilation
- Increase or decrease CO2 levels in body?
- Increase or decrease pH?

Answer 9

Decreases CO2 in the body

Increases pH

Question 10

6a9. Ultimately, what regulatory systems helps regulate H+ concentration in the body?

Answer 10

The respiratory centers in the brainstem

Question 11

6a10. How do the kidneys regulate pH?

Answer 11

1. Secrete H+ - distal convoluted tubule)
2. Reabsorb HCO3 (proximal convoluted tubule)
3. Synthesize HCO3 (proximal convoluted tubule)

Question 12

6a11. Respiratory acidosis
- Arterial blood gas levels of:
- p(CO2)?
- pH?

Answer 12

Increased CO2

Decreased pH

Question 13

6a11. Respiratory acidosis

- Some causes?

Answer 13

1. Emphysema
2. Pulmonary edema
3. Chronic bronchitis
4. Opioid overdose
5. Neuromuscular disease (myasthenia gravis, Guillian-Barre syndrome)
6. Injury to brainstem

Question 14

6a11. Respiratory acidosis

- Compensation?

Answer 14

1. Buffers act like bases

2. Kidneys increase their urine secretion of H+, reabsorption of HCO3, and synthesis of HCO3

Question 15

6a11. Respiratory acidosis

- Why isn’t the second line of defense, the respiratory system, involved in compensation against respiratory acidosis?

Answer 15

Typically because the patient is incapable of hyperventilation to decrease CO2 and increase the pH.

Question 16

6a12. Respiratory alkalosis
- Arterial blood gas levels of:
- pH?
- P(CO2)?

Answer 16

Increased pH

Decreased CO2

Question 17

6a12. Respiratory alkalosis

- Some causes?

Answer 17

1. Breathing at higher altitudes
2. Anxiety/fear
3. Salicyclic acid (aspirin) overdose
4. Fever

Question 18

6a12. Respiratory alkalosis

- Compensation?

Answer 18

1. Buffers act like acids

2. Kidneys decrease their urine secretion of H+, reabsorption of HCO3, and synthesis of HCO3

Question 19

6a13 Metabolic acidosis

• Arterial blood gas levels of:
  
  • pH?
  • HCO3?

Answer 19

1. Decreased pH

2. Decreased HCO3

Question 20

6a13 Metabolic acidosis

- Some causes?

Answer 20

1. Ketoacidosis: diabetes, alcoholism, fasting/starvation
2. Lactic acidosis
3. Ethylene glycol poisoning
4. Aspirin overdose
5. Severe diarrhea
6. Proximal (type 2) renal tubular acidosis in which proximal bicarbonate reabsorption is impaired

Question 21

6a13. Metabolic acidosis

- Compensation?

Answer 21

1. Buffers act like bases
2. Lungs undergo hyperventilation
3. Kidneys increase their urine secretion of H+, reabsorption of HCO3, and synthesis of HCO3

Question 22

6a14. Metabolic alkalosis
- Arterial blood gas levels of:
- pH?
- HCO3?

Answer 22

Increased pH

Increased HCO3

Question 23

6a14. Metabolic alkalosis

- Some causes?

Answer 23

1. Severe vomiting (emesis)
2. Gastric sunctioning
3. Renal H+ loss

Question 24

6a14. Metabolic alkalosis

- Compensation

Answer 24

1. Buffers act like acids
2. Lungs undergo hypoventilation
3. Kidneys decrease urine secretion of H+, reabsorption of HCO3, and synthesis of HCO3