Biochemistry (Respiratory) Flashcards
What is the normal range of hydrogen ion concentration?
35-45 nanomol/L so regulation is very tight.
What are some examples of H+ buffers in the body?
Haemoglobin, phosphate, bicarbonate and ammonium.
Why is the bicarbonate buffer so important?
Other buffer systems reach equilibrium but carbonic acid is removed as CO2, so the only limit is the conc of HCO3-.
What is the equilibrium equation for H+ and bicarbonate?
H+ + HCO3- H2CO3 CO2 + H2O
What is the equation involving pCO2, H+ and HCO3-?
[H+]=pCO2/[HCO3-]
What are the respiratory and metabolic components?
Respiratory: pCO2. Metabolic: HCO3-.
What is an acidosis and an alkalosis?
Acidosis: increase in [H+], or a process tending to cause increases in [H+]. Alkalosis: opposite.
What is an acidaemia and an alkalaemia?
Acidaemia is increase is [H+], alkalaemia is opposite.
What is there too much of when there is a metabolic acidosis?
H+
How is a metabolic acidosis corrected?
Bicarbonate equilibrium shifts to the right so they breathe off more CO2 (deep breathing).
What happens to the bicarbonate concentration in a metabolic acidosis?
Decreases as it is reacting with the extra H+.
What is the primary problem and the compensation in a metabolic acidosis?
Primary: too much H+, compensation: blow off more CO2.
What is there too much of in a respiratory acidosis?
CO2.
How is a respiratory acidosis corrected?
Bicarbonate equilibrium shifts to the left, more H+ excreted.
What is the primary problem and the compensation in a respiratory acidosis?
Primary is too much CO2, compensation is excreting more H+.
Describe how metabolic compensation for respiratory acidosis occurs in the kidneys.
CO2 from blood diffuses into renal tubular cells -> reacts with water so equilbrium shifts left -> H+ produced is then excreted into renal tubular lumen where it is buffered (lost from the body) -> bicarbonate goes into blood.
What is there too little of in a metabolic alkalosis?
H+.
How is a metabolic alkalosis corrected?
Equilibrium shifts left, to compensate you can hypoventilate (ability to do this is limited by hypoxia).
What is there too little of in a respiratory alkalosis?
CO2.
How is a respiratory alkalosis compensated?
Equilibrium shifts right, kidneys decrease bicarbonate reabsorption (more bicarbonate excreted, can take several days).
What are some of the causes of respiratory acidosis?
Choking, bronchopneumonia (lung tissue filled with fluid), COPD (due to inability to ventilate).
What are some causes of respiratory alkalosis?
Hysterical overbreathing, mechanical over-ventilation e.g. in intensive care units, raised intracranial pressure (stimulates respiratory centre).
What are some causes of metabolic acidosis?
Impaired H+ secretion e.g. renal failure, increased H+ production of ingestion, loss of bicarbonate.
What are some causes of metabolic alkalosis?
Loss of H+ in vomit (only with pyloric stenosis), alkali ingestion, potassium deficiency.
What does it mean when you say you can’t overcompensate physiologically?
Someone with acidosis isn’t going to go too far in compensation to develop alkalosis.
