Block 2b Regulation of Respiration Flashcards
Where is the respiratory center located?
nucleus of the tractus solitarious (NTS) of medulla oblongata / pons
How is the respiratory center innervated?
vagal & glossopharyngeal nerves
Dorsal Respiratory Group
part of the respiratory center that is responsible for inspiration
pneumotaxic center
part of the respiratory center that limits inspiration
Ventral Respiratory Group
part of the respiratory center that supplements the DRG as an overdrive mechanism for increased expiration & inspiration
What is the Hering-Breuer Reflex?
chemo and stretch receptors via vagus nerve prevent overstretching
What receptors serve as sensors for respiratory center innervation?
peripheral chemoreceptors, baroreceptors, mechano & chemo receptors in lung
What is the dominant regulator of quiet breathing?
DRG
In what range can pneumotaxic center limit inspiration?
3-40 breaths/min
How does the VRG supplement the DRG in hyperventilation?
sends signals to abdominal muscles
Where does chemical control of respiration occur?
at the chemosensitive area of the respiratory center to stimulate DRG
What is the major chemoregulator of respiration?
CO2
Why is blood H+ not such a great chemoregulator of respiration?
cannot diffuse across BBB
How does blood O2 affect respiration?
via peripheral signaling only when PO2 < 60 mmHg
Where are the chemoreceptors for O2?
carotid bodies & aortic bodies
What are the 2 types of sleep apnea?
airway obstruction & central
How is central sleep apnea caused?
by neural depression of the respiratory center
How airway obstruction sleep apnea caused?
congenital or obesity
What causes respiratory depression?
brain edema (inactivation of respiratory center) & anesthesia
What can cause Cheyne-Stokes breathing?
heart failure (lag time for gas diffusion) & brain damage (inactivated DRG suddenly activates with great force, cycle repeats)
What does the DRG do?
generates AP’s of increasing frequency to give slow, steady lung filling & regulation of inflation rate/max capacity
How does the pneumotaxic center work?
terminates ramp signal of the DRG
Describe the effect of CO2 on chemoregulation of respiration.
potent acute effect for 2-3 days, then weak chronic effect due to kidney regulation (increase HCO3, which eventually diffuses across BBB)
What factors increase sensitivity of chemosensitive center to CO2?
increased H+ or decreased CO2 by causeing increased alveolar ventilation
How does CO2 stimulate the chemosensitive area?
1) mainly H+ via CA, 2) modest direct effect of CO2
Why is CO2 the main chemical regulator of respiration?
freely diffuses across BBB
