1. Blood buffering system
4/17/2017
Blood buffering system

2. The pH of Body fluids The pH of blood is 7.35 – 7.45
Changes in pH below 6.8 and above 8.0 may result in death.

4. The pH of body fluids is maintained by three major buffer systems:
1- Carbonic acid–bicarbonate system.
2- Dihydrogen phosphate – hydrogen phosphate system.
3- The ability of proteins to act as either proton acceptors or proton donors at different pH values.
The carbonic acid–bicarbonate system is the principal buffer in blood serum and other extracellular fluids.
The hydrogen phosphate system is the major buffer within cells.

6. Proteins as a blood buffer
Proteins contain – COO- groups, which, like acetate ions (CH3COO-), can act as proton acceptors.
Proteins also contain – NH3+ groups, which, like ammonium ions (NH4+), can donate protons.

7. Respiratory and Renal regulation
Both the respiratory & renal systems work to regulate pH in acid-base imbalance; the respiratory system works in a matter of minutes & is maximal within hours while the renal (kidneys) system continues to function for days to restore pH within normal limits (WNL).

8. Respiratory Regulation of Acid-Base Balance
Respiratory regulation of pH is achieved through carbonic acid/bicarbonate buffer system
As carbon dioxide levels increase, pH decreases
As carbon dioxide levels decrease, pH increases
Carbon dioxide levels and pH affect respiratory centers
Hypoventilation increases blood carbon dioxide levels
Hyperventilation decreases blood carbon dioxide levels

9. Respiratory Regulation of Acid-Base Balance

10. Renal Regulation of Acid-Base Balance
Secretion of H+ into filtrate and reabsorption of HCO3- into ECF cause extracellular pH to increase
HCO3- in filtrate reabsorbed
Rate of H+ secretion increases as body fluid pH decreases .

11. Acidosis and Alkalosis
Acidosis: pH body fluids below 7.35
Respiratory: Caused by inadequate ventilation
Metabolic: Results from all conditions other than respiratory that decrease pH
Alkalosis: pH body fluids above 7.45
Respiratory: Caused by hyperventilation
Metabolic: Results from all conditions other than respiratory that increase pH

12. Respiratory Acidosis: CO2 ↑ pH ↓
Symptoms: Failure to ventilate, suppression of breathing, disorientation, weakness, coma
Causes: Lung disease blocking gas diffusion,
depression of respiratory center by drugs,
cardiopulmonary arrest, stroke, or nervous system disorders
Treatment: Correction of disorder, infusion of bicarbonate

13. Respiratory Alkalosis: CO2 ↓ pH ↑
Symptoms: Increased rate and depth of breathing, numbness, light-headedness, tetany
Causes: hyperventilation due to anxiety, hysteria, fever, exercise; reaction to drugs such as salicylate, quinine, and antihistamines
Treatment: Elimination of anxiety producing state, rebreathing into a paper bag

14. Metabolic (Nonrespiratory) Acidosis: H+ ↑ pH ↓
Symptoms: Increased ventilation, fatigue, confusion
Causes: Renal disease, hepatitis and cirrhosis; increased acid production in diabetes mellitus, hyperthyroidism, starvation; loss of alkali in diarrhea; acid retention in renal failure
Treatment: Sodium bicarbonate given orally, dialysis for renal failure, insulin treatment for diabetic ketosis

15. Metabolic (Nonrespiratory) Alkalosis: H+ ↓ pH ↑
Symptoms: Depressed breathing, confusion
Causes: Vomiting, diseases of the adrenal glands, ingestions of access alkali
Treatment: Infusion of saline solution, treatment of underlying diseases

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