| If ventilation increases with no change in metabolism, what does that mean | Hyperventilation
Increase in pO2
Decrease in pCO2 |
| What happens when ventilation decreases with no change in metabolism | Hypoventilation
Decrease in pO2
Increase in pCO2 |
| What does hypercapnia and hypocapnia mean | Hypercapnia means rise in pCO2
Hypocapnia means decrease in pCO2 |
| If there is hypoventilation, what can that cause | Decreased removal of carbon dioxide which leads to an increase in carbon dioxide concentration ( hypercapnia )
This leads to an decrease in pH --> respiratory acidosis
Kidneys then respond to this by increasing excretion of [HCO3-] which brings the pH near normal --> compensated respiratory acidosis |
| If there is hyperventilation, what can that cause | Removal of CO2 from alveoli is much more rapid then production
Alveolar CO2 concentration then falls which leads to an increase in pH → Respiratory Alkalosis
Kidneys respond by secreting less [HCO3-] so it returns near the normal pH
Compensated Respiratory Alkalosis |
| How does metabolic acidosis start | If tissues produce acid ( lactic acid ) this reacts with HCO3-
The fall in HCO3- leads to a fall in pH
Metabolic acidosis
This can be compensated by increasing ventilation |
| What monitors arterial pO2 | Peripheral chemoreceptors located in the carotid and aortic bodies |
| What effects happens when chemoreceptors are stimulated | Increase in volume and rate of respiration
Changes in circulation directing more blood to brain and kidneys
Increased blood pumping by the heart |
| What controls CSF pH | Central chemoreceptors respond to changes in the pH of cerebro-spinal fluid
CSF pH is determined by arterial pCO2
CSF [HCO3 - ] controlled by choroid plexus cells
Persisting changes in pH corrected by choroid plexus cells by changing [HCO3 - ] |
