Resp 8 Flashcards
“blackbox”
neural control of ventilation
skeletal muscled that control ventilation cannot…
contract spontaneously
Spontaneously firing networks of neurons in the brainstem are influenced by..
sensory and chemoreceptors, as well as higher brain centers
respiratory neurons in the medulla
control inspiratory and expiratory muscles (breathing)
neurons in the pons
integrate sensory info and interact with medullary neurons to influence ventilation
Rhythmic pattern of breathing arises from…
a neural network with spontaneously discharging neurons
nucleus tractus solitaire (NTS)
located in the medulla and contains the dorsal respiratory group (DRG) that mainly control inspiratory muscles via phrenic nerve and intercostal nerve
NTS receives input from…
peripheral mechanics and chemoreceptors
pontine respiratory group (PRG)
provides tonic input to DRG to help medullary networks coordinate a smooth respiratory rhythm (does not create the rhythm)
ventral respiratory group (VRG)
- pre-botzinger complex
- control muscles of active inspiration and expiration
- outputs that keep upper airways open
pre-botzinger complex
contain pacemaker neurons that may initiate respiration
ramping
activity if inspiratory neurons increase steadily through a positive feedback mechanism; at the end of inspiration, activity shuts off abruptly and expiration takes place
peripheral chemoreceptors
aortic and carotid bodies
aortic and carotid bodies
sense changes in arterial PO2 , PCO2, and pH and adjust ventilation accordingly
Which cells in the carotid bodies sense changes in arterial pressure and pH?
Type I glomus cells
peripheral chemoreceptors primarily respond to…
increases in CO2
central chemoreceptors
send info to DRG; provide continuous input to respiratory control center and respond mainly to changes in PCO2
irritant receptors
respond to inhaled particles or noxious gas
response to inhales particles or noxious gases
- bronchoconstriction by parasympathetic outputs
- leads to rapid, shallow breathing and turbulent airflow to deposit irritant in mucosa
- reflex initiates coughing or sneezing
stretch receptors
prevent over inflation of lungs; Hering-Breuer inflation reflex
