control of respiration Flashcards
what are the basic component of the respiratory control system?
sensory receptor
Central controller
Effectors
what are the components of sensory receptors?
chemoreceptors
lung receptors and others
proprio receptor
stretch receptors
what are the components of central controller?
pons
medulla
other parts of the brain
what are the components of effectors?
respiratory muscles
what are the 3 main groups of neuro center in the brain stem?
medullary receptor center
Apneustic center ———> LOWER PONS
pneumotaxic center —–> UPPER PONS
what are the components of the medullary receptor center
1- Inspiratory center –> Dorsal respiratory group of neurons
mainly associated with inspiration
2- Expiratory center –> ventral respiratory group of neurons –> RESPONSIBLE FOR EXPIRATION
in which nucleus are the neurons of DORSAL respiratory group of neurons?
Nucleus of tractus solitairus ( NTS)
what are the function of apneustic center?
abnormal breathing pattern –> DEEP prolonged inspiratory gasps following a brief expiration movement
help prolong inspiration in cases of abnormal breathing pattern
whats the function of pneumotaxic center?
inhibit or switch off inspiration —-> regulate inspiration volume and respiratory rate / switching between inspiration/ expiration
what would a stimulus in apneustics / pneumotaxic result in?
stimulation of these neurons apparently excites the inspiratory center in the medulla , prolonging the period of action potentials in the phenic nerve —> PROLONG CONTRACTION DIAPHRAGM PERIOD
Pneumotaxic inhibit it though
what is the function cerebral cortex?
can temporarily override the automatic brain stem centers
Responsible for VOLUNTARY ACTIONS OF BREATHING
cerebral cortex –> voluntary
brainstem/medulla –> autonomic
what happens in voluntarily hyperventilation?
you voluntarily increase the rate and depth of breathing –> WILL GET RID OF CO2 levels –> CO2 drops then PROTONS DROP too –> PH INCREASES –> RESPIRATORY ALKLAOSIS –> dizziness , lightheadedness , uncounsciousness due to reduced oxygen deliver to the brain then the BRAINSTEM AUTOMATICALLY TAKES BACK CONTROL -> NORMAL BREATHING RETURNS
what happens in voluntarily hypoventilation?
opposite
CO2 partial pressure increases and O2 pressure decrease –> MORE PROTONS —-> acidity decrease in PH –> body will try to increases ventilation to get rid of co2
what are the receptors that are sensory for INSPIRATORY CENTER? ( DORSAL RESPIRATORY GROUP)
peripheral chemoreceptors –> sensitive for O, CO2, H
Central chemoreceptors –> H
Lung stretch receptors
muscle and joint receptor
which receptors increases inspiratory center?
apneustic center
which receptor inhibit inspiratory center?
pneumotaxic center
what is the efferent organ of the inspiratory center? ( DRG)
diaphragm
what is the location of central chemoreceptors?
brain stem
ventral surface of of the medulla close to the inspiratory center
what is the goal of central of chemoreceptors?
drive alveolar ventilation and control breath rate
maintain arterial partial pressure of CO2
Low ph –> high co2 (and high proton )–> hyperventilation and increased breathing rate
high ph –> low co2 ( low proton ) —> hypoventilation and decreased breathing rate
what is the mechanism of activating of central chemoreceptorS?
change in ph of cerebrospinal fluid —- direct effect
change arterial partial pressure of CO2– indirect effect
these changes will directly affect the inspiratory center ( DRG)
what is the main drive of alveolar ventilation in normla individuals at the sea level?
Partial pressure of CO2 in arteries and CSF —- the proton level effect on central chemoreceptors (ph affect the central chemo receptor)
PCO2 is number one
but when o2 becomes less than 60 = it becomes number one
what is the location of peripheral chemoreceptors?
carotid bodies —-> glossopharyngeal nerve ( cranial nerve 9 )
aortic bodies –> VAGUS NERVE ( Cranial nerve 10 )
what is the goal of peripheral chemoreceptors?
control of breathing rate
drive alveolar ventilation ventilation
when does peripheral chemoreceptors take control?
when partial pressure of O2 is less than 60
whats the mechanism of activating peripheral chemoreceptors?
detect changes in arterial :
Partial pressure of O
Partial pressure of CO2 –> MOST SIGINIFACNT unless o is less than 60
PH
Regulate breathing rate
what are some examples that could cause an increase in breathing rate?
decreases in partial pressure of O ( when less than 60 is stimulates peripheral and inhibit central )
increase in partial pressure of CO2 -> stimulates both peripheral and central mainly central
Decrease in ph ( because increase CO2 ) –> Protons only work on peripheral not central
what is the main driving cause of alveolar ventilation in peripheral chemoreceptors ?
Partial pressure of O2 less than 60
what happens to chemoreceptors in COPD?
patient with COPD –> body adapts to the increased level of CO2 due to poor gas exchange –> central chemoreceptors are not working because they adapted –> become less sensitive to high co2 level ( new set point ) –> no hyperventilation
when central chemoreceptors are less sensitive to co2 , the body relies on peripheral chemoreceptors WHICH ARE MAINLY DRIVED BY PARTIAL PRESSURE OF O2 so dont give 100% oxygen SUPPLEEMENT SO YOU DONT RUIN THEM AND MAKE THEM ADAPT , keep it at 88-92%, if you give 100% the peripheral chemos will not work and further inhibit ventilation = MORE CO2 ACCUMULATION
how does lung stretch receptors affect respiration ?
mechanoreceptors found in smooth muscles of airways
DISTENSTION /STRETCH of lungs and airways will lead to INHIBITED INSPIRATION AND VENTILATION
what is hering breuer reflex?
prolong expiratory period
how does joint and muscle receptors affect respiration?
mechanoreceptors located in joint and muscles
LIMB MOVEMENT WILL LEAD TO INCREASED BREATHING RATE
important for the warmup before working out
how does irritant receptors affect respiration?
located between epithelial lining of the airways
Respond to noxious chemicals and particles THESE PARTICLES WILL LEAD TO INCREASED BREATHING RATE AND CONSTRICTION OF BRONCHIAL SMOOTH MUSCLES
how does J receptors ( Juxtacapillary ) affect respiration?
located in the alveolar wall –> near pulmonary capillaries
ENGORGEMENT of blood and increase in interstitial fluid WILL LEAD TO INCREASED BREATHING RATE
IN LEFT SIDE HEART FAILURE —-> engorgement of blood –> RAPID SAWLLOW BREATHING AND DYSPNEA
contributes to distress seen in patients
what is cheyne stokes breathing ?
period of hyperventilation FOLLOWED BY APNEA period of no breathing
what are the causes of cheyne stokes breathing?
severe hypoxemia –> HIGH ALTITUDE especially at night
Lesions in CNS –> brain damage
Cardiovascular diseases –> severe heart failure
what is the mechanism of cheyne stokes breathing?
apnea –> INCREASES CO2 cuz no ventilation to get rid of it —> STIMULATES VENTILATION MAXIMAMLY —> HYPERVENTILATION –> LOW PARTIAL PRESSURE OF CO2 below the set point –> INHIBIT THE RESPIRATION BECAUSE CO2 IS TOO LOW –> repeat
this is due to late regulation of ventilation properly –> receptors takes too long to respond
what is sleep apnea syndrome?
a group of disorders in which breathing during sleep stops for 10 seconds –> usually 20 times per hour
this stop will lead to blood deoxygenation
what are the causes and classifications of sleep apnea snydorome?
1- Central sleep apnea –> Due to decreased respiratory center output —> longer intervals between breathing
2- Obstructive sleep apnea –> Upper airway blockage despite normal airflow drive –> anatomical most likey –> most commonly obesity and excessive fat
3- mixed central and obstructive
what do you see in central sleep apnea and not obstructive?
periods of apnea no breathing due to the brain not sending stimulus for breathing
