control of breathing Flashcards
at rest what is the partial pressure of oxygen?
100mmHg
at rest what is the partial pressure of CO2?
40mmHg
what is breathing modulated by?
- reflexes (coughing)
- volitional control (breath hold)
- vocalisation (singing)
- physiological challenges (exercise)
- emotional events (crying)
what is the name of normal rhythmic breathing?
eupnea
what is the name for short breath?
dyspnea
normal rhythmic breathing is controlled by what?
- respiratory related neutrons
- central pattern generators
- respiratory motor neurons
what is the function of respiratory related neutrons (RRN)?
fire more APs during respiratory cycle
what is the function of central pattern generators (CPG)?
in brainstem (medulla oblongata), independently generate respiratory rhythm
what is the function of respiratory motor neurons?
innervate respiratory muscles, axons via phrenic nerve innervate diaphragm
brain receives respiratory neural signals via?
chemoreceptors and mechanoreceptors
what is the function of chemoreceptors in control of breathing?
detect chemical changes - feedback on blood partial pressure of oxygen and CO2 and blood pH
what is the function of mechanoreceptors in control of breathing?
provide mechanical feedback on mechanical status of lungs, chest walls and airways
what does the brainstem control?
- upper airway
- respiration
- temp
- HR
- BP
what is the term for a decrease in oxygen?
hypoxia
what is the term for an increase in CO2?
hypercapnia
what are peripheral chemoreceptors?
small highly vascularised bodies in the region of aortic arch and carotid sinuses
chemoreceptors in the aortic arch send info via which nerve?
vagus
chemoreceptors in the carotid sinuses send info via which nerve?
glossopharyngeal
peripheral chemoreceptors send info to which region of the brainstem?
NTS
what are central chemoreceptors?
clusters of neurons in the brainstem that are activated when partial pressure of CO2 increases (hypercapnia) or pH decreases
what is the effect of reduced partial pressure of oxygen on ventilation ?
little effect until PO2 drops to 60mmHg then there is progressive hyperventilation
where does hypoxic response originate?
carotid and aortic bodies
what is the result of increases PCO2 on ventilation?
small change in PCO2 has large effect of ventilation (unlike O2)
where does hypercapnia response originate?
central chemoreceptors
in the respiratory system, what do mechanoreceptors detect?
movement of lungs and chest wall
describe the action of mechanoreceptors in respires to lunch inflation?
inflation of lungs activates mechanoreceptors, they send neural signals via the vagus nerve to NTS
NTS then adjusts ventilation accordingly
where may mechanoreceptors be found?
airway smooth muscle and airway epithelium
where does the NTS receive info from?
peripheral chemoreceptors and mechaoreceptors
information entering the NTS is processed by what?
respiratory neurons in the brainstem
which neurons activate inspiration?
inspiratory neurons
which neurons activate expiration?
expiratory neurons
rhythmic signals are sent to which nerve in the spinal cord?
phrenic
which nerve carrying rhythmic signals innervates the diaphragm?
phrenic
where is the dorsal respiratory group and which type of neurons does it contain?
in NTS, contains mainly inspiratory neurons
where is the ventral respiratory group and which type of neurons does it contain?
medulla oblongata in brainstem, both expiratory and inspiratory neurons and motor neurons
which respiratory group modulates respiratory output?
pontine respiratory group
which region of the brain controls voluntary actions which can alter airflow?
primary motor cortex
