Regulation of respiration Flashcards
What is the general location of the pneumotaxic center?
Upper pons
What is the general location of the apneustic center?
Lower pons
What are the respiratory centers in the brainstem?
Pneumotaxic center
Apneustic center
Dorsal respiratory group
Ventral respiratory group
Where is the inspiratory area mainly located?
Dorsal respiratory group
Where is the expiratory area mainly located?
Ventral respiratory group
What afferents does the DRG receive?
From vagus and glossopharyngeal carrying stimulation from baroreceptors, chemoreceptors, and mechanoreceptors
What is the function of the pneumotaxic center?
Sends efferents to DRG to inhibit inspiration, leading to shorter and more rapid respiration
Modulates the apneustic center activity
Fine tunes breathing pattern
What are the efferents of the DRG?
Through phrenic N and intercostal nerves to the muscles of inspiration
To VRG
What is the advantage of the inspiratory ramp signal?
Causes steady increase in the volume of the lungs during inspiration instead of inspiratory gaps
What is the inspiratory ramp signal?
2 seconds of contraction of inspiratory muscles followed by 3 seconds of relaxation then repeated
What nuclei of the brainstem contain parts of the ventral respiratory group?
Retrofacial nucleus
Nucleus ambiguus
Nucleus retroambigualis
Where is the Botzinger complex located?
VRG
What is the function of the Botzinger complex?
Expiratory neurons inhibit inspiratory cells in the DRG and some of the phrenic motor neurons
Where is the respiratory rhythm generator?
Cells in the pre-Botzinger complex
What is the function of motor efferents from the VRG?
Muscles of larynx, pharynx, and tongue to keep the upper airway patent
What is the nucleus the pneumotaxic center is located?
Nucleus parabrachialis
What are the functions of the apneustic center?
Delay the switch-off point of the respiratory camp by acting on the DRG –> increased inspiration and decreases RR
What inhibits the apneustic center?
Pneumotaxic center
Vagus
What is the effect of a bilateral vagotomy just above the apneustic center?
Prolonged inspiratory gasps –> apneusis
What is Kussmaul breathing and what is it associated with?
Deep, labored, gasping breathing pattern
Associated with severe metabolic acidosis like diabetic ketoacidosis and renal failure
What is ataxic breathing and what is it associated with?
Clusters of cyclic irregular breathing followed by recurrent periods of apnea
Seen with medullary lesions
What is Biot’s breathing?
Special type of ataxic breathing characterized by breaths of nearly equal volume separated by long periods of apnea
What is the Hering-Breuer inflation reflex?
Inflation to tidal volume stimulates stretch receptors to send afferents to DRG to stop inspiration
What is the Hering-Breuer deflation reflex?
Deflation of lung decreases afferents from stretch receptors, stimulating inspiration
What is the most important stimulus for peripheral chemoreceptors?
Hypoxia –> decreased PaO2
What can also stimulate peripheral chemoreceptors other than hypoxia?
Increased PaCO2
Increased [H+] –> decreased pH
What is the location of central chemoreceptors?
Bilaterally in the ventrolateral medulla in contact with CSF
What is the major chemoreceptor responsible for breathing rate?
Central chemoreceptors responding to PaCO2
What can stimulate central chemoreceptors?
Increased PaCO2
Increased [H+] –> decreased pH
What chemoreceptors does metabolic acidosis primarily act on?
Peripheral
Which chemoreceptors are more sensitive? Which are quicker?
Central are 7x more sensitive
Peripheral are 5x quicker
