Physio 4 Flashcards
what are the mechanisms for regulation of respiration
neural and chemical
what are the neural mechanisms of regulation and by what
voluntary by cerebral cortex
involuntary by brainstem ( pons and medulla)
what is the chemical regulation and by what
monitor o2 and co2 levels
by central and peripheral chemoreceptor
what is the neural automatic mechanism to establish a rhythmic breathing pattern
medullary respiratory center
what centers are present in medullary respiratory center
Dorsal respiratory group (DRG)
Ventral respiratory group (VRG)
Pneumotaxic center
what does the ventral respiratory group responsible for (charac)
inspiratory and expiratory neurons
inactive during quiet breathing
active during active / forced respiration
stimulate expiratory signals to abdominal muscles
what does the dorsal respiratory group responsible for (charac)
inspiratory neurons only
dormant during expiration
pacemaker
stimulate inspiratory muscles
what does the pneumotaxic centern responsible for (charac)
sends impulses to DRG to switch off inspiratory neurons
control switch off point of inspiratory ramp so control duration of filling phase of lung cycle
pneumotaxic signal strong
inspiration last for 0.5 sec so filling the lungs slightly
pneumotaxic signal is weak
inspiration lasts for 5 sec so filling the lungs with excess air
where is the chemosensitive area of respiratory center
beneath ventral surface of medulla
what is the chemosensitive area sensitive to
changes in co2 and H+ ( h+ indirect and less effect)
what is the respiratory reflex
rapid automatic adjustment in pulmonary ventilation
baroreceptor, stretch, chemoreceptor, irritating and others
what is the stretch receptor
located in muscular portion of bronchi and bronchiole and it responds to changes in lung volume and send signals through vagus nerve to DRG
What is the feedback response of stretch receptor
decrease inspiration when lung overinflated
where is the central and peripheral chemoreceptors
central in medulla oblongata
peripheral in carotid and aortic arteries
what do central and peripheral chemoreceptors detect and monitor
central detect ; interstitial co2 and monitor arterial co2 indirectly
peripheral detect; arterial co2 and monitor alveolar ventilation
what is the main regulator of ventilation in central chemoreceptors
carbon dioxide generated H+
What are peripheral chemoreceptors weakly and strongly responsive to
weakly ; arterial co2 changes
strongly ; increased arterial H+ conc
what stimulates central and peripheral chemoreceptors
central : increase H+
peripheral : arterial PO2 below 60 mmhg
peripheral chemoreceptor respond to changes of chemical content of arterial blood
true
what causes hypercapnia and hypocapnia
hypercapnia by hypoventilation
hypocapnia by hyperventilation
whhen PO2 levels below 60 mmhg what is triggered
respiratory center (DRG)
When co2 levels rise by 10% what happens to RR
Doubled
if PCO2 levels get too low what happens
unconsciousness
where are baroreceptors located
aortic and carotid sinus
what is baroreceptor reflex pathway
baroreceptors in aortic and carotid sinuses are monitored by sensory neurons in glossopharyngeal and vagus nerve then transmitted to respiratory center
what happens in BP falls below normal
Respiratory center is stimulated
respiration and BP have an inverse RS
true
what is the protective reflex (irritant )
coughing or sneezing which is an apnea followed by forceful expulsion of air ( apnea ; period in which breathing has stopped )
what is the inflation and deflation reflex activated by
stretch receptors in lungs during forced expiration ( TV above 1000ml)
inflation reflex prevents what
overexpansion of lungs
inhibits inspiratory center and stimulate expiratory center
deflation reflex inhibits and stimulates what
inhibits expiratory center and stimulate inspiratory center
what is Hering Breuer reflex
Slowly adapting stretch R (SARs) located in bronchial airway only activated suring exercise to prevent excess lung inflation and terminate inspiration
what is the apneustic center
stimulates inhalation by continuous stimulation of medulla oblongata
send impulses to DRG to delay switch off signal of inspiratory ramp by pneumotaxic center
what controls intensity of breathing and what controls the filling duration of lung cycle
intensity : apneustic center (sends positive impulses to inspiratory neurons)
duration of filling : pneumotaxic center
what inhibits apneustic center
pneumotaxic center
location of baroreceptors, stretch receptors, chemoreceptors
baroreceptor ; carotid and aortic sinus
stretch receptor in smooth muscles of bronchi and bronchiole
central chemo; medulla
peripheral chemo; aortic and carotid artery
glossopharyngeal and vagus nerves involved in what reflex
baroreceptor
vagus nerve involved in what reflex
stretch receptor
