Respiratory: Acid Base Balance - Lecture 1 Flashcards
How many millimoles of H+ are produced by the metabolism daily?
60 millimol H+ are produced by metabolism daily
Is urine alkaline or acidic by nature?
Acidic due to the body excreting the H+ ions
99.9% of H= ions are excreted in urine.
Describe the buffering of the H+ ions using the bicarbonate system?
o H+ + HCO3- ↔H2CO3 ↔CO2 + H2O
Describe the buffering of the H+ ions using the Haemoglobin system?
o H+ + Hb- ↔ HHb
Describe the buffering of the H+ ions using the Phosphate system?
o H+ + HPO42- ↔H2PO4-
Describe the buffering of the H+ ions using the Ammonium system?
o H+ + NH3 ↔NH4+
Describe the importance of Bicarbonate?
- Other buffer systems reach equilibrium
- Carbonic acid (H2CO3) is removed as CO2
- The only limit is the initial concentration of HCO3-
What is the name of the condition with too many H+ ions called ?
Ketonacidosis
Describe Ketonacidosis?
- Body will use up bicarbonate buffer to shift equilibrium to the right to compensate
- In patients with ketonacidosis, there will be low levels of HCO3-
- Body will blow off CO2 to balance this out
o H+ + HCO3- ↔H2CO3 ↔CO2 + H2O
What is the name of the condition with too CO2 and too much acid in the blood ?
Respiratory acidosis
What are the problems associated with respiratory acidosis?
- COPD occurs when the exchange of gases is not efficient resulting in hypoxia (lack o O2) and an increase of CO2 in the blood
- Reaction equilibrium is shifted to the left
- The increase in H+ is balanced by increased excretion of H+
o H+ + HCO3- ↔H2CO3 ↔CO2 + H2O
What is the body’s compensation mechanism if it has too much H+ ions?
Lungs blow off CO2
What is the body’s compensation mechanism if it has too much CO2?
Kidney’s get rid of H+ ions
What does Acidaemia mean?
- Acidaemia; increased [H+]
What does Alkalaemia mean?
- Alkalaemia; decreased [H+]
What is an Acidosis?
A Process tending to cause increased H+
What is an Alkalosis?
A process tending to cause decrease H+
In arterial blood gases what is the respiratory component?
The pCO2
The whole process is considered a Respiratory problem if the change is in the pCO2
In arterial blood gases what is the Metabolic component?
The HCO3 -
o It is a metabolic process if the primary change is in HCO3-
Describe what causes a respiratory acidosis?
Increased [H+] due to increased pCO2
Describe what causes a Respiratory alkalosis?
Decreased [H+] due to a decreased pCO2
Describe what causes a Respiratory acidosis?
Increased [H+] due to an decreased HCO3-
Describe what causes a Metabolic alkalosis?
Decreased [H+] due to an increased HCO3-
If the primary disorder is an increase in pCO2 (respiratory acidosis), what is the compensatory response?
Increase in HCO3-
If the primary disorder is a decrease in pCO2 (Respiratory alkalosis) what is the compensatory response?
decrease in HCO3-
If the primary disorder is a decrease in HCO3- (Metabolic acidosis) what is the compensatory response?
Decrease in pCO2
If the primary disorder is an increase in HCO3- (Metabolic alkalosis) what is the compensatory response?
Increase in pCO2
What do blood gas machines estimate?
- H+
- pCO2
- HCO3-
- pO2
What are some causes of an acidosis?
- Choking
- Bronchopneumonia
- COAD
What are some of the causes of an alkalosis?
- Hysterical overbreathing
- Mechanical over-ventilation
- Raised intracranial pressure
How is Bicarbonate recovered?
o H+ + HCO3- ↔H2CO3 ↔CO2 + H2O - Tis occurs in the renal tubular lumen
The H2O and the CO2 move accross into the renal tubules
H2O + CO2 -> H2CO3
H2CO3 -> HCO3- + H+
The HCO- moves into the Peritubular capillary
The H+ moves into the renal tubular lumen, were it reacts is HCO3-
