Control of ventilation Flashcards
What are the three basic elements of respiratory control?
- Sensors
- Central controller
- Effectors
What part of the brain controls patterns of inspiration and expiration?
Pons and medulla
Which nerves provide input about to the inspiratory center?
Vagus- pulmonary stretch receptors
Glossopharyngeal- Carotid bodies
What happens if you transect between the spinal cord and medulla?
Breathing stops
What happens if you cut the vagus nerve and midpoint?
Prolonged inspiratory effort
What happens when you cut the pons and midbrain and cut vagus?
Slow deep breathing
Where does respiratory rhythmicity originate?
Medulla and fine tuned by the vagus and higher centers within the brain (pons)
When do you get apneusis?
Pontine off-switch is not working or there is no vagal input
What happens to inspiration muscles during exhalation at exercise?
They are inhibited. They can not both be active at the same time
Can breathing be under voluntary control?
Yes the cortex is able to cause hypo or hyperventilation
What are muscles of inspiration?
Diaphragm, external intercostals, sternomastoids, scalene
What are muscles of expiration?
Abdominals, internal intercostals
Where are central chemoreceptors found?
Ventrolateral surface of medulla bathed in ECF
What do central chemoreceptors detect?
They detect CO2 because nothing else can get across the blood brain barrier. This changes the pH of the CSF and ECF because it produces H+
Where are peripheral chemoreceptors?
Common carotid bifurcation (carotid bodies) and aortic arch
What are carotid bodies sensitive to?
PO2, PCO2, and pH
How much ventilatory drive do the carotid bodies provide at rest?
20%
How much ventilatory drive to central chemoreceptors provide at rest?
80%
Which is the most important sensor in exercise?
Carotid bodies
Why do people who sprint breathe from O2 tanks?
This high oxygen level knocks out the peripheral chemoreceptors so you breathing slows down. This can interfere with ability to get rid of lactic acid however
What other receptors can increase ventilation?
- Nose and upper airway receptors
- Muscle spindles
- Muscle and joint receptors
- Temperature and pain receptors
- Arterial baroreceptors
How long does it take for air to reach the central chemoreceptors?
2 or 3 breaths
Which sensor can sense pressure of O2 below 100mmHg?
Peripheral chemoreceptors
