Module 5: Acids and Bases

Question 1

Primary Regulators of Acid-Base Balance

Answer 1

Lungs and kidneys

• respiratory acids are eliminated as CO₂ during ventilation
• metabolic acids are eliminated by the kidneys as H⁺ in the urine

Question 2

Acid

Answer 2

any compound that generates H⁺ ion in solution

Question 3

Base

Answer 3

any compound that accepts/ binds H⁺ ion in solution

Question 4

Buffer

Answer 4

• neutralizing compound that resist pH changes
• Simplest form:
  
  • H₂O –> H⁺ + OH^-
• buffers present to minimize fluctuations in pH should:
  
  • be in buffer pairs = conjugate base and weak acid
  • dissocatie well at a neutral pH

Question 5

pH equation

Answer 5

pH = -log [H⁺]

**pH of blood is 7.35-7.45**

Question 6

Henderson-Hasselbach Equation

Answer 6

pH = pk + [base]/[acid]

Question 7

Henderson-Hasselbach Equation and the bicarbonate buffer system

Answer 7

pk = 6.1

have to convert P_CO2 into its soluble acid H₂CO₃ with its solubility coefficient = 0.03

P_CO2 *0.03 =H₂CO₃

Question 8

Bicarbonate Buffer System Equation

Answer 8

CO₂ +H₂O H₂CO₃ H⁺ + HCO₃^-

Question 9

Common causes of respiratory acidosis

Answer 9

1. airway obstruction
2. disorders of lung tissues
3. respiratory depression due to oversedation, brain stem trauma
4. disorder of chest wall
5. paralysis of respiratory muscles
6. advanced COPD
7. asthma
8. sleep apnea

**pH <7.35 and hypercapnia (high CO₂)

Question 10

Respiratory Acidosis

Answer 10

• low pH, high CO₂
• causes potassium shift to the ECF due to the H/K shift; increases the free Ca²⁺
• lack of ventilation in relation to metabolic production of carbon dioxide

Question 11

Metabolic Acidosis

Answer 11

• acids in the blood (excluding H₂CO₃ ) are increased
  
  • when acid is high in the blood, it soaks up HCO₃^- due to the buffer role bicarbonate plays and lowers the levels of bicarbonate
• or bicarbonate is lost
• pH < 7.35, HCO₃^- <24
• **potassium shift to the ECF due to the H/K shift; increases free Ca²⁺
• *****ANION GAP**** used to determine cause of metabolic acidosis

Question 12

Causes of Metabolic Acidosis

Answer 12

1. certain types of diarrhea
2. lactic acidosis due to poor perfusion or hypoxia
3. Renal failure
4. diabetic ketoacidosis
5. ingestion (methanol, ethylene glycol [antifreeze])

Question 13

Anion Gap

Answer 13

• used to determine the cause of Metabolic Acidosis
• normal range 8-16
• equation:
  
  • ANION GAP = ([Na⁺] + [K⁺]) - ([HCO₃^-] + [Cl^-])
• if anion gap is HIGH, suggests that an acid is “soaking” up HCO₃^-

Question 14

Respiratory Alkalosis

Answer 14

• levels of CO₂ in the blood are low due to excess ventialtion relative to carbon dioxide production
• pH >7.45 abd hypocapnia
• **potassium shift to the ICF due to H/K shift, hypokalemia, and low serum free Ca²⁺

Question 15

Common Causes of Respiratory Alkalosis

Answer 15

1. anxiety, panic disorders
2. excess mechanical ventilation
3. hypermetabolic states:
   
   1. fever
   2. anemia
   3. thyrotoxicosis
4. pregnancy–> increased progesterone increases RR

Question 16

Metabolic Alkalosis

Answer 16

• Retention of HCO₃^- or excessive loss of metabolic acids
• pH>7.45, high HCO₃^-
• ***potassium shift to the ICF , hypokalemia, less free serum Ca²⁺***

Question 17

Common Causes of Metabolic Alkalosis

Answer 17

1. vomiting
2. too much gastric suction
3. antacids/ excessive bicarbonate intake
4. hyperaldosteronism with hypokalemia
5. diuretics

Question 18

Arrow trick for metabolic vs. respiratory alkalosis vs acidosis

Answer 18

Question 19

Calculation Method and Steps for the types of Acid-Base Imbalances

Answer 19