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what is the volume of air that can be inhaled with maximal effort from the tidal end-inspiratory level?
inspiratory reserve volume (IRV)
what is the volume of air that can be exhaled with maximal effort from a rest tidal end-expiratory level?
expiratory residual volume (ERV)
what is the amount of air that remains in the lungs after a maximal effort exhalation?
residual volume (RV)
how can you measure residual volume?
with He dilution, N2 washout, or body plethysmography (body box) with boyle's law
what is the amount of air in the lungs after a maximal-effort inspiration?
total lung capacity (TLC)
what is the maximum amount of air that can be exhaled after a maximal-effort inspiration?
what is the maximal limits of a single breath, from deepest inhalation to blasting it all out as long and hard as possible?
what is the amount of air that can be inhaled with maximal effort from a resting tidal volume end-expiration level?
inspiratory capacity (IC)
the inspiratory capacity can be reduced by factors that affect ______ _________, such as emphysema?
what is the amount of air remaining in the lungs at the end of a normal tidal exhalation, with no accessory muscle use?
functional residual capacity (FRC)
what is the balance point of lung's elastic recoil inward and outward expansion of the chest wall?
functional residual capacity
what is the average cwp of the pleural space pressure?
-3 to -5 cwp below atmospheric pressure at end exhalation
due to the elastic recoil of the lungs, the lungs have a natural tendency to want to do what?
due to the elastic recoil of the lungs, and the natural tendencies of the lungs, ribs, and chest, this creates what?
an equilibrium in forces
what are the airway pressure gradients?
although pressure is commonly expressed in cwp, sometimes it is expressed relative to the atmospheric pressure, where 760mmHg is changed to ___?
PL is equal to (balances out) the _______ ______ forces of the lungs when airflow is absent?
what is the difference in pressure between the pleural space and the body surface; pressure across chest wall?
no airflow exists at the end of inspiration or at the end of exhalation because _____________?
in normal breathing, Prs changes only when the PA changes because Pao remains at ___ (atmospheric)?
what disrupts the balance between recoil forces of lungs and outward recoil forces of the chest wall?
when muscles of inspiration contract, thoracic volume ____________ and pressure in the cavity ____________ (boyle's law)?
what establishes a pressure gradient (Prs) and air flows into the lungs?
when PA falls to less than Pao at the mouth
when airflow stops (when PA rises to = Pao); ______________________ gradient is the greatest, and volume is highest (500ml)?
after Ppl rises, PA then rises above ___ as alveoli shrink, causing what?
gas to flow out of lungs
when the diaphragm descends, causing thoracic volume to increase, in turn causes what to happen?
intra-pleural and intra-alveolar to both decrease (boyle's law)
exhalation is _______, diaphragm ___________ and goes _____; causing drop in ______ volume, and increase in ___ and ___?
pleural space pressure is always ________ during spontaneous ventilation, only changes to more or less __________?
pleural space pressure changes with ________ pressure breaths from machines, it can become ___ or even ________?
what are the 2 static forces that want to collapse the lungs?
surface tension of alveoli
elastic properties of lungs (inward recoil)
what is the natural ability of matter to respond to a force, and then return back to original shape once force is removed?
elastic resistance includes what?
elastic recoil properties of lungs and the alveolar surface tension present
during elastic resistance-- retractive forces and elastance want to do what as much as possible and must be overcome to start inhalation?
keep the lung collapsed
what cause nonelastic resistance?
by things that produce friction during airflow (muscle, cartilage, fat, blood vessels, airways, secretions)
the more compliant the lung is, the more ________ or ________ _________ it is?
the more compliant the lung is, means there is a ________ volume change for a ______ change in pressure applied
a disease associated with the less compliant the lung, the stiffer it is and harder to inflate?
what is it called when you place a pause or hold on an inspired breath from the ventilator to stop gas flow, and then record a pressure measurement?
plateu pressure (Pplat)
if pt is on PEEP, what must you do?
subtract that value from the pressure before solving the reset of the equation for both compliance types
emphysema does what with elastic recoil fibers in the lungs? and what does that mean?
they have a higher compliance but low elastance
are emphysema lungs floppy or stiff? how do they inflate? and how do they recoil?
do not recoil well
decreased compliance means _________ lungs, ______ volume changes for ________ pressure changes?
how is surface tension created?
at the surface, molecules below and adjacent are attracted=the liquid wants to contract
what does the recoil pressure in the air-filled lungs reflect?
the retractile forces of the elastic fibers, plus surface tension of the alveoli
law of Laplace is a physics law that states what?
the tension on the wall of a sphere is the product of the pressure times the radius of the chamber
if there is just one liquid/gas interface, we can set up a equation for ________ ________?
if we have 2 bubbles (alveoli) connected by a common tube (bronchiole), the P would be __________ in the smaller bubble if the surface tension is the same in both?
the smaller bubble is really prone to ________, because it has a higher surface tension, while the bigger bubble needs less P to keep it open?
because of the connection with the tube, the little bubble would do what?
tend to collapse and empty into the big bubble
what lowers surface tension of smaller alveoli so that the distending pressure to keep all sizes of alveoli open is constant throughout the lungs?
what alters surface tension in larger alveoli- it actually increases it if necessary to keep the distending pressure at a constant for all sizes?
what has a great effect on the amount of surfactant and its action in the alveoli?
alveolar surface area
as the surface area of the alveoli decreases, the surface tension dramatically decreases because what?
there is more surfactant concentrated together and works harder
big alveoli spread out the surfactant more, so it does not exert its influence as much, which actually will allow what?
the surface tension to increase somewhat thereby balancing things in the system
what are conditions that can cause surfactant deficiency?
ARDS, IRDS, pulmonary edema, pulmonary emboli, pneumonia, excessive pulmonary lavage, near drowning
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