Quantitative Acid-Base Balance Flashcards
What is acid-base balance in the body?
It is the regulation of [H+] in body fluids which is difficult due to continued production of H+ and CO2
What is the normal arterial pH?
7.4
What are volatile acids and non-volatile acids?
Volatile - H2CO3
Non-Volatile - Produce H+
Where is the regulation of H+ most crucial?
Intracellularly
Where is the H+ that the kidneys and the lungs act on?
Extracellular
Does the regulation of the extracellular H+ affect the intracellular H+?
Yes. H+ transfer from the intracellular space to the interstitial space is slow but from the interstitial space into the plasma is fast
How is the regulation of the extracellular H+ related to the intracellular space regulation of bicarbonate and CO2?
Bicarbonate - reabsorption from the tubular space to plasma space is low
CO2 - proton transfer as CO2 from the plasma space tot eh alveolar air is fast
What is the flow of H+ in the body?
H+ goes from the
- intracellular space to the interstitial space (slow)
- then to to the plasma (fast)
- then is removed via the lungs or kidneys
What has more capacity to reduce acidity, the lungs or the kidneys?
Lungs.
For example, the lungs exhale CO2 (13,000 mmol/day) and the kidneys excrete H+ (50 mmol/day) and reabsorb HCO3– (5,500 mmol/day).
Thus the lungs have 150 times the capacity of the kidneys to remove acidity: 150 = (13,000 mmol – 5,500 mmol) / 50 mmol.
What induces strong K+ shifts?
Mineral acids like HCl where H+ is exchanged for K+
What induces weak K+ shifts?
Organic acids like lactic acid and carbonic acid
What acid is involved with metabolic acidosis?
Lactic Acid
What acid is involved with respiratory acidosis or alkalosis?
Carbonic Acid
How is chemical buffering involved with maintaining arterial plasma [H+]?
- Pi buffering
- HCO3- buffering
- Protein buffering (Hb)
How is the renal system involved with maintaining arterial plasma [H+]?
Kidneys secrete acidic urine (H+/NH4+/H2PO4-)
and absorb HCO3-
