Chemical Control of Breathing Flashcards
What happens to pO2 and pCO2 in hyperventilation?
pO2 rises
pCO2 falls
What happens to pO2 and pCO2 in hypoventilation?
pO2 falls
pCO2 rises
What does hypercapnia do to plasma pH?
Leads to a fall in plasma pH
What does hypocapnia do to plasma pH?
Leads to a rise in plasma pH
Where are peripheral chemoreceptors located?
Carotid and aortic bodies
What do large falls in pO2 stimulate?
1) Increased breathing
2) Changes in heart rate
3) Changes in blood flow distribution - eg increasing flow to brain and kidneys
Where are central chemoreceptors located?
Medulla of the brain
Central chemoreceptors respond to changes in pH of what?
CSF
What is CSF [HCO3-] controlled by?
Choroid plexus cells
Is the blood brain barrier permeable or impermeable to HCO3-?
Impermeable
What is the range for pCO2?
4.7-6.0 kPa
What is the range for pO2?
9.3-13.3 kPa
What is the range for bicarbonate?
22-26mmol/L
What is type I respiratory failure?
Type 1 respiratory failure is defined as a low level of oxygen in the blood (hypoxemia) without an increased level of carbon dioxide in the blood (hypercapnia)
What is type II respiratory failure?
Type 2 respiratory failure is caused by inadequate alveolar ventilation; both oxygen and carbon dioxide are affected.