Regulation L39 Flashcards
Name the 4 components that tightly control breathing rate and tidal volume
- chemoreceptors
- mechanoreceptors
- brain stem control centers
- respiratory muscles
voluntary control of breathing can be exerted by what?
- cerebral cortex
- when? breath holding or voluntary hyperventilation
- temporarily override brain stem
name the two respiratory control centers in the brain stem
- pons respiratory centers
- medullary respiratory centers
name the three parts of the medullary respiratory centers
- rostral ventromedial medulla
- dorsal respiratory group
- ventral respiratory group
name the two parts of pons respiratory center
- pneumotaxic center
- apneustic center
where is the inspiratory center located
dorsal respiratory group (DRG)
*comprises of cells in the NTS
dorsal respiratory group (DRG) receives input from peripheral chemoreceptors via what two nerves
- glossopharyngeal nerve
- vagus nerve
dorsal respiratory group (DRG) receives input from mechanoreceptors in lungs via what nerve
vagus nerve
the inspiratory center sends motor output to what muscle via what nerve?
- diaphragm
- phrenic nerve
inspiration is shortened by inhibition of the inspiratory center via what?
pneumotaxic center
location and function of pneumotaxic center
- upper pons
- turns off inspiration
how does pneumotaxic center turn off inspiration
- limits burst of action potentials in the phrenic nerve
- thus limits size of tidal volume and secondarily regulates respiratory rate
where is the expiratory center located
ventral respiratory group (VRG)
are ventral respiratory group (VRG) neurons generally active or inactive during regular breathing?
inactive because expiration is generally passive
*center becomes active during exercise
what is apneusis breathing
- abnormal breathing pattern
- prolonged ispiratory gasps followed by brief expiratory movement
how does apneusis breathing occur. List steps
- stimulation of apneustic center in the lower pons
- stimulation of apneustic center excites inspiratory center in medulla (DRG)
- prolonged action potential in phrenic nerve
- prolonged diaphragm contraction
- prolonged inspiratory gasps
what can temporarily override automatic brain stem centers
commands from cerebral cortex
- e.g. hyperventilation
hyperventilation affect on PaCO2 and arterial pH
- PaCO2 decreases
- arterial pH become more basic
hypoventilation affect on PaCO2 and PaO2
- PaO2 decreases
- PaCO2 increases
what is the most important information that chemoreceptors sends to the brain stem
CO2 levels
chemoreceptors send what information to brain stem
- PaO2
- PaCO2
- arterial pH
rate and depth of breathing are regulated to keep PaCO2 at
40 mmHg
what happens to ventilation during sleep state
- when you sleep you tolerate increases in CO2 levels without changing ventilation
- decreased sensitivity to PaCO2
what else can decrease sensitivity to PaCO2
- narcotics
- alcohol
- anesthetics
what are the most imporant regulators of inspiration
central chemoreceptors
brain stem chemoreceptors are sensitive to changes in ?
changes in pH or CSF
- decreased pH -> hyperventilation
- increased pH -> hypoventilation
medullary chemoreceptors respond directly to a change in and respond indirectly to a change in .
- pH of CSF
- PaCO2
Is CO2 permeable across the blood brain barrier?
yes, it can enter the CSF where it is converted to H+ and HCO3- (drops pH)
- thus increase in PaCO2 will increase CSF PCO2 and central chemoreceptors will detect decrease in pH
main goal of central chemoreceptors
keep PaCO2 within normal range
where are peripheral chemoreceptors located
- aortic arch : aortic bodies
- bifurcation of CCA : carotid bodies
peripheral chemoreceptors send what information to medually inspiratory center
- PO2
- PCO2
- pH
information from peripheral chemoreceptors travels where and via what nerves?
- medullary inspiratory center
- CN IX and CN X
what is the most important thing that peripheral chemoreceptors detect
PaO2
- they respond if PaO2 < 60 mmHg -> increase breathing rate
If peripheral chemoreceptors detect and increase in PaCO2, what will happen to the breathing rate
increase
which peripheral chemoreceptors are able to detect a change in arterial pH
only peripheral chemoreceptors in carotid bodies
give two examples of mechanoreceptors
- lung stretch receptors
- joint and muscle receptors
where are lung stretch receptors located
airway smooth muscle
lung stretch receptors are activated by? results in?
- distension of lungs and airways
- results in decrease in breathing rate ( by prolonging expiration time)
what is the hering-breuer reflex
prevents over-inflation of lungs
joint and muscle receptors are activated by? and result in?
- limb movement
- result in increase breathing rate
- important in early ventilatory response to exercise
irritant receptors are located where?
between epithelial cells lining the airways
irritant receptors are activated by? result in?
- dust/pollen
- increase breathing rate and constriction of bronchial smoooth muscle
juxtacapillary receptors are located where?
alveolar walls
juxtacapillary receptors are activated by? and result in?
- engorgement of pulmonary capillaries with blood
- result: increase breathing rate
does brief apnea have effect on PaO2 and PaCO2
no because episodes are shorter than 10 seconds
what is the most common type of sleep apnea
obstructive sleep apnea
what causes obstructive sleep apnea
- upper airway closes during inspiration
- airway is obstructed and airflow will cease
- associated wit brief periods of self-arousal
obstructive sleep apnea is due to the stimulation of peripheral and central chemoreceptors detecting ?
- arterial hypoxia and arterial hypercapnia
what is central sleep apnea
- occurs when there is a decreased ventilatory drive to the respiratory motor neurons
- no respiratory efforts are made
- no pleural pressure ossillations
which type of sleep apnea has pleural pressure oscillations?
- obstructive sleep apnea
- pleural pressure oscillations increase as CO2 increases
- central apnea has no pleural pressure oscillations
