Mechanism of regulation
First line of defence- Blood buffers
1. Bicarbonate
2. Phosphate
3. Protein
Second line of defence -Respiratory regulation
1. Hypoventilation
2. Hyperventilation
Third line of defence - Renal mechanism
1. Excretion of H+
2. Conservation of HCO3-
3. Excretion of titrable acid
4. Excretion of ammonium ions
Bicarbonate buffer
Major buffer in ECF
Bicarbonate: carbonic acid in a ratio of 20:1
pKa-6.1
It is main buffer system because
a. High HCO3 -concentration
b. Components are under physiological control, CO2 by lungs and HCO3- by kidneys
Phosphate buffer
Major intracellular buffer
Na2HPO4: NaH2PO4 in a ratio of 4
pKa-6.8
More potent because pKa value is nearer to the body pH
Protein buffers
Hemoglobin
Albumin
Imidazole group of histidine is the most effective contributor in this buffer system
26 апр 2019
