Normal Resp Flashcards
What is transmural pressure?
Pressure inside the container minus the pressure outside the container
What does the positive transpulmonary pressure do?
Works to expand the container
Thorax expands and lungs follow
What does a negative transpulmonary l pressure do?
Works to collapse the container
Elastic recoil in the lungs
What is the elastic recoil pressure?
The natural tendency of lungs to collapse
Due to connective tissue and surface tension in the alveoli
What pressure opposes the lungs recoil pressure?
Transpulmonary pressure
An increase compliance means there is ____ recoil force
less
Decreased compliance means there is ____ recoil force
More
What is pleural pressure?
The negative pressure of the pleural cavity
What is compliance?
The extent the lungs expand for each unit increase in transpulmonary pressure (pleural pressure minus alveolar pressure)
What is a surface active agent which greatly reduces the surface tension in the alveoli?
Surfactant
What is the naturally occuring contractile force for all of the air spaces within the lungs?
Surface tension elastic force
What is the normal volume of air inspired or expired with each normal breath?
Tidal volume
500 mL
What is the extra volume of air that can be inspired over and beyond the normal tidal volume?
Inspiratory reserve volume
3000 mL
What is the extra amount of air that can be expired by forceful expiration after the end of a normal tidal expiration?
Expiratory reserve volume
1100 mL
What is the volume of air still remaining in the lungs after the most forceful expiration?
Residual volume
1200 mL
What is minute respiratory volume?
Tidal volume x respiratory rate
The total amount of new air moved into the respiratory passages each minute
6 L/ minute in men 5 L/ minute in women
What keep us from completely saturating our blooding to carrying capacity?
Physiological shunts
blood leaks between ventilatory system and bronchioles
How are the pulmonary arteries able to accommodate about 2/3 of the stroke volume output of the right ventricle each time the heart beats?
They are very thin and distensible- giving them a large compliance
What part of the lung is the most pressure needed to get blood to?
The apex
What are the three factors that influence diffusion in the lungs?
Concentration gradient
Surface area
Membrane thickness
What is the most important factor for gas exchange in normal physiology?
Concentration gradient
What is the driving pressure for bulk flow in the airways?
Barometric pressure at the mouth minus alveolar pressure
What is a metabolically active gas?
One that is exchange across the membrane
ex- oxygen use in ATP production
CO2- Krebs cycle
What is an inert gas?
Not exchange across tissue membranes
Ex- nitrogen
What is a partial pressure of a gas?
pressures that the individual gases would exert if each gas were present alone in the volume occupies by the whole mixture at the same temperature
What happens to the partial pressures of gases when air saturates with water?
Decreases
What happens to air in the conducting zone?
Warmed to 37 C and 100% saturated
PO2 gradients is _____ from alveoli to blood
large
PCO2 gradient is _____ from blood to alveoli
small
lung diffusion capacity of O2 is _____
small
Lung diffusion capacity for CO2 is _____
large
what relationship must be balanced for the lungs to operate optimally?
Ventilation- perfusion
What happens with lung overinflation?
Doesn’t allow normal alveolar partial pressures to be maintained
What happens with lung under-inflation?
there is inadequte O2 uptake and CO2 removal
What is the ideal alveolar ventilation perfusion ratio?
0.8
What is the normal resp rate in children?
18-24 resp/ min
What is the normal resp rate in infants?
40-60/ minute
What is the respiratory center?
Several groups of neurons located bilaterally in the medulla
What are the four components of the respiratory center?
Dorsal Respiratory Group (DRG)
Ventral Respiratory Group (VRG)
Pneumotaxic Center
Apneustic center
What does the pnemotaxic center do?
controls the “switch-off” point of the inspiratory ramp, limits inspiration
What doe the apneustic center do?
Inhibits the pneumotaxic center; stops the switch off signal
What 2 parts are found in the pontine areas?
Pneumotaxic center
Apneustic center
What does the pontine area do?
Stabilizes respiratory rhythm and depth
What two parts are in the medullary rhythmicity area?
Dorsal Respiratory Group (DRG)
Ventral Respiratory Group (VRG)
What does the medullary rhythmicity area do?
Rhythm generator- delivers reptitive bursts of action potentials (pacemaker potentials)
What does the dorsal respiratory group (DRG) do?
Stimulates phrenic nerve to drive the diaphragm and intercostal nerves to control external intercostal muscles (ramp signal)
What does the ventral respiratory group (VRG) do?
Contains both inspiratory and expiratory neurons
Inspiratory- accessory muscles of inspiration
expiratory- internal intercostals and abdominal muscles for ACTIVE expiration
the ventral respiratory group is _____ during normal breathing and becomes active during _____
Quiescent; exercise
What does the pneumotaxic center transmit signals to? what does it do?
DRG; control the “switch off” of inspiration
Limits inspiration
What is apneusis?
abnormal breathing pattern with prolonged inspiratory gaps followed by brief expiratory movement
What does stimulation of the apneustic center cause?
Apneusis
What two centers does the DRG recieve input from?
Apneustic and pneumotaxic centers
Chemoreceptors are primarily drive by ___
CO2
What do central chemoreceptors respond to?
Increased arterial PCO2
Act by way of increasing CSF (H+)
What are carotid bodies sensitive to?
PaO2 (think low O2)
PaCO2
pH
What are aortic bodies not sensitive to?
pH
What does the Hering- Breuer Reflex prevent?
Overinflation- terminates inspiration, prolongs expiration
What to juxtapulmonary receptors (J-Receptors) respond to?
Increased interstitial volume
