Lecture 26 Acid Base Balance Flashcards
What is essential for cellular function
regulation of [H+] of body fluids is essential
what is highly sensitive to [H+]
protein structure and function are highly sensitive to [H+] pH= -log [H+]
increase [H+] = decrease pH
Neutral pH
7
[H+] = 10(-7) mol/L = 0.0000001 mol/L
Normal pH of ECF
is 7.4 slightly alkaline
What is the central acid base system of the body
CO2-bicarbonate system
CO2+ H20 -><- H+ + HCO3-
carbonic anhydrase catalyzes reaction in both directions
CO2 acts as
an acid
increase CO2 -> increase [H+] = decrease pH
HCO3- acts as
a base
increase HCO3- -> decrease [H+] = increase pH
Buffers
bicarbonate (CO2-bicarbonate system)
proteins (e.g. hemoglobin)
phosphate compounds
Acid-base regulation
- role of the respiratory system
- role of the kidneys
- acid-base imbalances
Role of respiratory system
respiratory system regulates PCO2 of blood via control of ventilation
decrease VA -> increase PCO2 (hypoventilation) -> decrease pH
increase VA-> decrease PCO2 (hyperventilation) -> increase pH
Role of the kidneys
kidneys regulate [HCO3-] of blood via H+ excretion and HCO3- reabsorption
increase [HCO3-] -> increase pH
acidosis
pH < 7.35
alkalosis
pH > 7.45
respiratory acidosis/alkalosis
is deviation from normal pH due to change in PCO2
metabolic acidosis/alkalosis
is deviation from normal pH due to change in non-CO2 acids/bases -> results in change in [HCO3-]