Lecture Notes: Understanding Acidosis and Alkalosis

Overview

• Acidosis and Alkalosis: Conditions affecting blood pH (acidic or basic).
• Blood pH Range: Normal is between 7.35 and 7.45.
  • Acidosis: Below 7.35.
  • Alkalosis: Above 7.45.

Measurement

• pH Measurement: Measures hydrogen ion (H⁺) concentration.
• Additional Factors: To determine if acidosis/alkalosis is respiratory or metabolic, other blood factors are analyzed.

Key Equation

• Breathing & CO2:
  • Breathing produces CO2.
  • CO2 mixes with water in blood → forms carbonic acid (H₂CO₃).
  • Carbonic acid dissociates into bicarbonate ions (HCO₃⁻) and hydrogen ions (H⁺).
  • Acidosis: Increase in hydrogen ion concentration.
  • Alkalosis: Decrease in hydrogen ion concentration.

Types of Acidosis/Alkalosis

Respiratory Acidosis/Alkalosis

• Respiratory Acidosis:
  • Cause: Increased CO2 levels.
  • Process: More CO2 → more carbonic acid → more H⁺ ions → lower pH.
• Respiratory Alkalosis:
  • Cause: Decreased CO2 levels.
  • Process: Less CO2 → less carbonic acid → fewer H⁺ ions → higher pH.

Metabolic Acidosis/Alkalosis

• Metabolic Acidosis:
  • Causes: Increase in H⁺ ions or decrease in bicarbonate (HCO₃⁻).
  • Process: Less bicarbonate to buffer H⁺ → lower pH.
• Metabolic Alkalosis:
  • Causes: Increase in bicarbonate or decrease in H⁺ ions.
  • Process: More bicarbonate relative to H⁺ → higher pH.

Conclusion

• Compensation: Body typically compensates for imbalances, e.g., breathing adjustments to expel CO2.
• Blood Analysis: Important for diagnosing and differentiating between acidosis/alkalosis types.

This lecture provides a framework for understanding how respiratory and metabolic processes influence blood pH and the conditions of acidosis and alkalosis.