acid-base balance

Proper pH balance is crucial for body function.
Deviations from pH range can lead to:
  - Denaturing of proteins:
    - Denaturing: When a protein changes its shape due to changes in pH, leading to loss of function.
    - Proteins need to maintain a specific shape for optimal function; about 90% of cellular work relies on proteins.
  - Dysregulation of potassium balance, potentially causing arrhythmias and vasodilation.

Free hydrogen ions determine pH.
Sources of hydrogen include:
- Dietary intake of hydrogen-rich foods (fats and proteins).
- Increased metabolism, leading to higher levels of carbon dioxide and lactic acid, both contributing to free hydrogen ions.
Mechanisms for reducing excess hydrogen:
- Kidneys: Secretion of hydrogen into filtrate for excretion.
- Lungs: Regulation of carbon dioxide levels.

Increased metabolism leads to:
- Increased carbon dioxide and water, which can form carbonic acid.
- Increased carbonic acid results in more bicarbonate and free hydrogen ions.
Regulation of carbon dioxide affects free hydrogen and thus pH:
- If metabolism increases carbon dioxide, increase respiratory rate to expel CO₂.
- If CO₂ is low, reduce respiratory rate.

Definition: Decrease in pH due to factors other than carbon dioxide (unlike respiratory acidosis).
Causes include:
  - High protein or high-fat diets.
  - Excessive exercise leading to high acid production.
  - Severe diarrhea (loss of bicarbonate).
  - Renal dysfunction causing inadequate hydrogen secretion.

Definition: Increase in pH due to factors other than carbon dioxide.
Can occur due to:
  - Excessive vomiting leading to loss of stomach acid.
  - Ingestion of alkaline substances (e.g., baking soda).
  - Renal dysfunction causing excess secretion of hydrogen.

Buffering of Hydrogen:
   - Quick response (happens in seconds).
   - Buffers can bind free hydrogen ions, reducing their impact on pH.
   - Main buffers include:
     - Bicarbonate (converts to carbonic acid).
     - Proteins and phosphates.
Respiratory Compensation:
   - Takes minutes to change pH.
   - Adjusts pH by changing respiratory activity:
     - Decreased blood CO₂ leads to increasing respiratory rate.
     - Increased CO₂ prompts increased ventilation.
   - Detected by peripheral chemoreceptors, driving changes in ventilatory activity.
Renal Compensation:
   - Takes hours to days to regulate pH.
   - Key functions of kidneys:
     - Secreting hydrogen ions and reabsorbing bicarbonate.
     - Creating new bicarbonate from intercalated cells in the distal tubule and collecting duct.
   - In the proximal convoluted tubule:
     - Bicarbonate reabsorption coupled with hydrogen ion secretion.
   - In extreme cases, renal system can utilize glutamine to produce bicarbonate and release ammonium, eliminating excess hydrogen.

Definition: Low pH due to hypoventilation (under-breathing).
Results in increased CO₂, leading to increased free hydrogen.
Compensation: Renal system increases secretion of hydrogen and reabsorption/production of bicarbonate.

Definition: High pH due to hyperventilation (over-breathing).
Causes decreased CO₂ and free hydrogen ions, thus raising pH.
Compensation: Renal system reduces hydrogen secretion and decreases bicarbonate reabsorption.

Definition: Increased free hydrogen leads to lowered pH, independent of CO₂.
Commonly associated with renal issues.
Compensation primarily through respiratory adjustments (increased ventilation).

Definition: Decreased free hydrogen leads to raised pH, independent of CO₂.
Compensation involves respiratory changes to hold CO₂, increasing free hydrogen in plasma.

Review changes in blood pH, normal pH range, causes of acid-base disturbances, and compensation mechanisms.
Feel free to ask questions for clarification as needed.