buffering flashcards
What is a buffering system?
A system that absorbs excess hydrogen ions (H⁺) or hydroxyl ions (OH⁻) to prevent significant changes in pH, maintaining homeostasis.
Where are buffering systems located?
In both intracellular and extracellular compartments.
What are the four main buffering systems?
- Carbonic acid-bicarbonate buffering 2. Protein buffering 3. Renal buffering 4. Bone buffering
What does the carbonic acid-bicarbonate buffer system do?
It operates in the lungs and kidneys, helping maintain pH by adjusting CO₂ and bicarbonate (HCO₃⁻) levels.
How do the lungs affect the carbonic acid-bicarbonate buffering system?
The lungs can adjust CO₂ levels through breathing. Hyperventilation blows off CO₂, raising pH in acidosis, while hypoventilation retains CO₂, lowering pH.
How do the kidneys affect the carbonic acid-bicarbonate buffering system?
The kidneys can reabsorb bicarbonate or generate new bicarbonate to neutralize excess H⁺ in acidosis, taking hours to days to adjust pH.
What is respiratory compensation?
The lungs adjust ventilation to respond to changes in pH, either blowing off CO₂ in acidosis or retaining CO₂ in alkalosis.
What is renal compensation?
The kidneys reabsorb bicarbonate or secrete hydrogen ions to balance pH, particularly in conditions of acidosis or alkalosis.
What is protein buffering?
Intracellular proteins, such as hemoglobin, buffer pH by binding or releasing H⁺. Hemoglobin also carries CO₂ and H⁺ to the lungs for excretion.
How does hemoglobin contribute to protein buffering?
Hemoglobin carries H⁺ and CO₂ away from tissues to be excreted via urine (H⁺) and ventilation (CO₂), helping correct acidosis.
What is renal buffering?
The kidney’s distal tubule regulates acid-base balance by secreting excess H⁺ into the urine and reabsorbing bicarbonate into the plasma.
What happens to H⁺ ions in renal buffering during acidosis?
The kidneys secrete excess H⁺ into the urine to help balance the pH.
What is bone buffering?
The skeleton, containing alkaline reserves like hydroxyapatite, releases alkaline substances to balance blood pH in acidosis.
How does the bone respond to acidosis?
The bone releases alkaline materials, such as calcium and phosphate, by breaking down (via osteoclasts) to neutralize excess acid and restore pH balance.
