Respiratory Flashcards
Which volume remains in the lungs after a maximal expiration?
Residual volume (volume you can’t move out unless detached)
Which of the following is not a muscle of inspiration?
a. diaphragm
b. external intercostals
c. sternocleidomastoid muscles
d. internal intercostals
e. anterior scaleni
D. Internal intercostals (muscle of expiration)
Do the abdominal and internal intercostal muscles actively contract during normal tidal breathing?
No, it is passive (unless have ailment)
During exercise, one needs to exchange more gas into and out of the lungs. Why?
Increasing metabolic rate so need more oxygen because you need to burn more fuel
What happens to IRV during exercise? What muscles are involved in this adaptation?
Decreases, accessory muscles of inspiration (sternocleidomastoid, anter. serrati, scalene)
What happens to ERV during exercise? What muscles are involved in this adaptation?
Decreases, accessory muscles of expiration (internal intercostals, abdominal)
FRC is always the amount of gas remaining in the lungs when chest wall elastic recoil and lung elastic recoil are ___
equal and opposite! (if not the lung and chest would be moving, the FRC is where the lung and chest wall come to rest)
vital capacity
4500-5000mL, max amount of gas we can move
total lung capacity
5700-6200 mL, includes RV + VC
do we have more inspiratory reserve or expiratory reserve?
inspiratory reserve, more energy efficient thing to do is increase inspiration because our inspiratory muscles are. used all the time so it is easy to recruit more of them
expiratory reserve volume
1000-1200mL, extra volume with recruitment of accessory muscles
inspiratory reserve volume
3000-3300mL, recruit more volume with accessory muscles to increase gas exchange
As the respiratory system volume gets smaller, lung elastic recoil pressure ___ and chest wall outward elastic recoil pressure ___
decreases, increases (to a certain point)
as the respiratory system volume enlarges, the lung elastic recoil pressure __ and the chest wall outward recoil pressure ___
increases, decreases
the total respiratory system elastic recoil pressure is the sum of
lung elastic recoil pressure + chest wall elastic recoil pressure
at lung volume of 4.5L the chest wall is at its equilibrium position so the chest wall elastic recoil pressure is ___
neither inward or outward
at lung volume of 4.5L the chest wall is at its equilibrium position therefore the total respiratory system elastic recoil pressure depends on ____
lung elastic recoil pressure (inward)
ALWAYS INWARD UNLESS PNEUMO
at respiratory volume >4.5L the chest wall elastic recoil pressure becomes ___
an inward recoil pressure
at what volume is chest wall outward recoil pressure maximal?
1200- residual volume (when maximally compressed)
at TLC the direction of lung elastic recoil pressure is maximally ___ and the direction of the chest wall elastic recoil pressure is _____
inward, inward
what is the equilibrium position of the detached lung?
collapsed
at what point during a normal tidal breath does the lung reach its equilibrium position?
it doesn’t unless you have a pneumo.
during normal tidal breathing the pressure gradient responsible for moving air into and out of the lungs is represented by the difference between ___
atmospheric and alveolar pressures (Pbarometric - Palveolar = delta P)
How can a healthy person generate an increased rate of expiratory gas flow from the lungs?
exercising- reduce reserve by utilizing more, increase expiratory gas flow, more oxygen demand more gas exchange by taking larger volume, increase elastic recoil, recruit accessory muscles
Does lung fibrosis change the intrinsic elastic recoil of the lung?
Yes, (think thick rubber band- extra collagen- increase lung elastic recoil)
Does lung fibrosis change the intrinsic elastic recoil of the chest wall?
No
How does lung fibrosis impact FRC?
increase Pel inward and chest wall outward (same)
so increase in Pel = smaller volume = decreased FRC
At FRC someone with lung fibrosis will have what sized alveoli compared to a healthy person?
Smaller (decreased compliance, smaller volume in alveoli, can’t stretch d/t fibrotic tissue)
Does being supine affect FRC?
Yes! increase WOB, decrease chest wall recoil outward pressure, gravity won’t allow it to fully expand, so decrease FRC
Does the elastic recoil pressure in your lung change as you move from FRC to TLC?
Yes, the length changed (extrinsic), increase in volume, more stretch, increase Pel, at TLC Pel and chest wall both inward
How does the chest wall move with inspiration?
upward and outward
How does the sternum move during inspiration with someone who has a complete transection at C7?
move inward d/t negative intrapleural pressure because diaphragm is still moving so it is pulling everything down
Would the volume of gas that remains in the lungs at end expiration (FRC) be changed by a C7 transection
wouldn’t be able to push as much air out, FRC would be less, less pulling outward
Why would someone who aspirated recruit their accessory muscles to breathe after expelling the water?
lost surfactant (alveoli collapsed) so increase in ALI, increase Pel, increase WOB, need to drive more pressure in to overcome adhesive forces
In terms of positioning when is FRC maximal? lowest?
Maximal- standing upright, lowest- lying with head tilted down
How does body position affect FRC?
affected by extrinsic factors, the length of the fibers, when standing upright gravity pulls lungs down, when laying down with your head tilted back- guts push up reducing the outward chest recoil, decrease compliane, diameter volume and FRC, increase resistance and wob
Does closing volume change with body position?
No, depends on intrinsic factors
If an emphysema patient has a closing volume of 3 L and an FRC of 3.5 L what lung mechanical difficulties would they have when they lie down?
increased closing volume, decreased lung elastic recoil, FRC lowers
What advantage could dynamic compression serve?
cough- more effective when gas molecules are closer to airway wall to help move mucous up the airway
During passive expiration the driving pressure for gas out is
Pa-Pb
During forced expiration the driving pressure for gas out is
Pa - Ppl
Compare dynamic compression of the airways of emphysema patients to healthy patients
Emphysema- earlier airway closure, increase gas trapping, greater dynamic compression
Why do systolic and diastolic pressures change vertically across the lung?
gravity
How does pulmonary capillary pressure and alveolar pressure influence the flow of blood through pulmonary capillaries?
Ppc < Palv. otherwise would constrict
Regional distribution of Blood Flow - Zone 1
Doesn’t usually exist in healthy individuals, no blood flow, apex level, systolic 10/ dialstolic 0
Regional distribution of Blood Flow - Zone 2
Intermittent blood flow, heart level, systolic 25/diastolic 8
Regional distribution of Blood Flow - Zone 3
Continuous blood flow, base level, systolic 33/diastolic 16
How does being supine affect pulmonary distribution of blood flow?
gravity less effect, more blood flow, small distance between anterior and posterior, the posterior will be the dependent region
How does PEEP effect zone 1?
increase in Pa, increase tendency to get zone 1, more pressure on capillary so less blood flow (change in alveolar pressure)
How does hemorrhage effect zone 1?
decrease in pulmonary systolic, pulmonary capillary pressure, and mean pressure, pulmonary pressure < Pa (change in pulmonary pressure)
How does exercise effect zone 1?
increases blood flow, diastolic would increase, would be continuous rather than intermittent
Nondependent region of lung
upper lobe, above heart
ventilation: intrapleural pressure more negative, greater transmural pressure gradient, alveoli larger, less compliant, less ventilation
perfusion: lower intravascular pressures, less recruitment, higher resistance, less blood flow
Dependent region of lung
lower lobes
ventilation: intrapleural pressure less negative, smaller transmural pressure gradient, alveoli small, more compliant, more ventilation
perfusion: greater vascular pressure, more recruitment, lower resistance, greater blood flow
Why are alveoli in the bases smaller?
gravity, pulls tissues down and compresses
What effect does gravity have on lung inside the chest cavity?
pulls the alveoli in nondependent region down making them larger and compress the alveoli in the dependent region making them smaller
Dependent region of lung
smaller alveoli, more compliant
Nondependent region of lung
larger alveoli, less compliant
When a forced expiration takes lung volume down to closing volume which lung region will be more likely to collapse?
Dependent close first- less elastic lung recoil, smaller, less radial traction, increase surface tension in airway
When at RV which lung region will inflate first during the next inspiration?
nondependent will open first until can pop open the lower
What lung pathologies would lead to increased airways resistance?
asthma, emphysema - increased radial traction, loss of elastic recoil, easier for them to inhale than to exhale
Transmural pressure
across the wall of the airway
Transpulmonary pressure
across the alveoli
