Flashcards in Control of ventilation & Pulmonary mechanics Deck (102)
The central chemoreceptors are stimulated by _______ H+; an increase in cerebral spinal fluid CO2 automatically leads to an ______ in H+.
______ drives normal respiration.
The peripheral chemoreceptors are stimulated by ______ PCO2, ______ pH, and/or _____ PaO2 (<60mmHg).
increased; decreased; decreased
The _______ nerve carries sensory impulses from the carotid bodies, and the _____ nerve carries sensory impulses from the aortic bodies and also from stretch receptors in the lung parenchyma.
glossopharyngeal nerve--> carotid bodies
vagus nerve---> aortic bodies and lung parenchyma
The glossopharyngeal nerve carries sensory impulses from the _______, and the vagus nerve carries sensory impulses from the _______ and also from stretch receptors in the _______.
The glossopharyngeal nerve carries sensory impulses from the carotid bodies, and the vagus nerve carries sensory impulses from the aortic bodies and also from stretch receptors in the lung parenchyma.
The diaphragm is the muscle of inspiration. ______ % of TV alone is all due to the diaphragm. The rest is from the _________ nerve.
50-75%; external intercostal
_______ are our built in ABG's.
-only kick in when PaO2 <60
Why is it BAD to give chronic O2 patients too much O2?
because they rely on their chemoreceptors--> their chemoreceptors kick in when PaO2 <60... we knock out this function when giving them O2
DRG stands for:
doral respiratory group
VRG stands for:
ventral respiratory group
DRG generates the basic rhythm of respiration, it is found in the medulla, and may be considered the ________.
The VRG can influence BOTH _______ and ________.
inspiration and expiration (internal intercostals)
*probably comes into play when high levels of ventilation are required
The pneumotaxic center is located _________. The apneustic center is located ________.
pneumo: high in the pons
apneu: low in the pons
The ________ SHUTS OFF inspiration.
*apneustic center also has similar function
The ______ work together to control the RATE and DEPTH of inspiration.
pneumotaxic and apneustic centers
The smooth muscle of the bronchi and bronchioles has receptors that FIRE when STRETCHED, which reflexly tends to INHIBIT inspiration. This is called the _______.
In adults, the Hering-Breuer reflex does not become important until TV exceeds ____.
In neonates the Hering-Breuer reflex is _______ and ______.
STRONG and RELEVANT
*protective mechanism for preventing excess lung inflation
In the Hering-Breuer reflex, the ______ nerve carries afferent (sensory) information.
Central chemoreceptors respond to _________.
*H+ concentration in CSF increases as PaCO2 increases and decreases as PaCO2 decreases--> normally CO2 drives ventilation
Peripheral chemoreceptors respond to 3 things???:
1) decreased PaO2 <60
2) increased H+ concentration
3) increased PaCO2
When the partial pressure of CO2 in CSF increases, the H+ and HCO3- ion concentrations increase immediately.... who's principle or law applies?
Le Chatliers---> derives from law of mass action---> want to achieve equilibrium
Ventilation and perfusion in the UPRIGHT, SPONT VENT, NON-INTUBATED person is BEST in the ______ lung.
The intrapleural space (potential space) is found between parietal pleura of internal chest wall and visceral pleura covering the lung. The intrapleural pressure is "negative" (subatmospheric) b/c the lungs recoil inward and the chest wall recoils outward--> when the inward and outward forces are equal this is called FRC. Which part is altered in the obese patient? In the patient with emphysema?
obese= chest wall
in both instances FRC is altered
~ 3L FRC is normal in the upright, spont breathing 70kg person
During inspiration intrapleural pressure becomes more _______. Air enters the lung because the intrapulmonary pressure is ______.
negative (subatmospheric--> can't actually have a negative pressure)
The _______ couple the lungs to the chest wall.
_______ pressure (pressure between the inside of the chest wall and lungs) is ALWAYS negative (subatmospheric) during normal tidal breathing.
Intrapleural pressure becomes more ______ during inspiration and less _______ during expiration. Intrapulmonary pressure is ______ during inspiration and more ______ during expiration.
Intrapleural becomes more negative during inspiration and less negative during expiration.... intrapulmonary is negative during inspiration and positive during expiration
What are 2 scenarios when intrapleural pressure may become positive?
1) during forced expiration
2) expiratory effort against a closed glottis (valsalva)