**Lesson 8: Lung Volumes Flashcards
while everyones lung volume is dependent on who they are, what is something that is roughly the same between us all?
the ratio in lung volume between breathing and all that stuff
what is your capacity to breath all the way in all the way out called?
vital capacity
all the volumes and capacities of lung volumes can change when exercising except for?
- vital capacity
- residual volume
- total lung capacity
what is tidal volume?
the size of each individual breath (from the end of your inspiration, to the end of your expiration)
what is functional residual capacity (FRC)?
the volume of air in your lung at the end of a passive expiration
what does the FRC represent from a respiratory mechanics point of view?
represents the natural relaxation volume of the respiratory system
- the volume where we have a balance between the outward chest wall forces and the inward elastic recoil forces of the lung
- we rest here
if you have a highly compliant lung, will your FRC be at a higher or lower volume?
higher
at the end of a passive exhalation, what is the capacity that we have to breath in?
our IC (inspiratory capacity)
the FRC is closely related to?
the IC
if our FRC goes up in lung disease, what does the IC do?
goes down
what is the IRV (inspiratory reserve volume)?
the volume you have available to breathe in at the end of tidal inspiration
can we change our IRV without changing our IC?
yes. if we breath in a little bit more, our IRV will change but not our IC. Our IC is in relation with our expiration, whereas the IRV is in relation to our inspiration. If we were to exhale a little more, then our IC will change
if someone is breathing at too high of a lung volume, what may happen?
they will not be able to increase their tidal volume during some sort of stress like exercise or asthma attack
what is hyper inflation?
someone breathing at a high lung volume
someone with obesity may have the same tidal volume as someone without, but what will change?
their IC will be bigger because they are breathing a lower lung volume because it is easier for them because of the mass on their chest
- FRC will be lower
how will someone with obesity have an affected ERV?
they are breathing with the same tidal volume just at a lower lung volume because it is easier. so there expiratory reserve volume will be lower so if they try to exhale more, they will not be able to.
why do we look at flow and volume of the lung together?
helps us determine if there is a healthy respiratory system. We look at capacities of the lung
the change in volume is a function of?
time
how can we determine flow?
by forced maneuvers
what is FEV1?
- forced expiratory volume in one second
- the volume of air expired during the first second of a maximal expiratory effort starting from TLC
- how much volume you can expire in one second
what is FVC?
- forced viral capacity
- similar to vital capacity, but measured during a maximal expiratory effort starting from TLC
what does the FEV1/FVC ratio tell us?
relative to your vital capacity, how much air could you move out in the first second
- (about 70-80%)
if you are an athlete, can you train your lung tissue to be stronger?
no. being an early athlete may influence in a bit but no.
what is the difference in FEV1/FVC ratio between normal and obstructive?
FVC is the same, but FEV1 is smaller in obstructive therefore making the ratio smaller
why does a restrictive lung have a smaller FEV1?
because they have less lung volume to begin with
what is the difference in FEV1/FCV ratio between normal and restrictive?
restrictive FVC is lower and so is FEV1
as you go leftwards on a flow volume curve, what does that represent?
that represents increasing lung volume up to total lung capacity
as you go rightwards on a flow volume curve, what does that represent?
that represents emptying the lung all the way to residual volume
what is negative flow on the flow volume curve?
the inspiration flow
- everything above zero is expiration flow
what is the small loop on the flow volume curve?
- tidal volume
- resting flow volume loop
what does the dashed line on the flow volume curve represent?
if you start picking up the flow of your breathing (picking up your breathing)
what does the big, solid, funky line on the flow volume curve represent?
maximal flow volume determined by a forced vital capacity procedure
what is peak expiratory flow?
- when we have a huge recoil pressure, we increase them
- we recruit our expiratory muscles to increase air/flow
peak expiratory flow goes down as?
recoil pressure goes down
why can we hear breathing at the beginning of an exhale only?
because the flow rate is high
what is FVC on the flow volume curve/loop?
the difference in TLC and RV
what is the difference in the volume flow curve in someone with healthy lungs vs COPD?
someone with COPD has a lower peak expiratory flow and they have an impairment in max expiratory flow. so there is scooping where it should be a flat line down. it represents airflow obstruction
why is the FEV1 value going to be lower in individuals with COPD?
because of the small airways and the airflow obstruction
what is the difference in the volume flow curve from a healthy lung to restrictive disease lung?
the top of the restrictive breath is a lower value compared to the healthy individual, they can generate a peak expiratory flow without a scoop. their FEV1 is lower because the FVC is lower
summary of COPD (obstruction) and the FEV1/FVC curve
- able to inflate
- severe limitations with expiration
- combination of airways narrowing (high R) and loss of elastic recoil (highly compliant lung)
- flow limitation on expiration leads to low FEV1/FVC ratio
- <0.7
summary of ILD (restriction) and the FEV1/FVC curve
- cannot inflate sufficiently
- largely due to poor lung compliance (stiff lungs)
- low FEV1 is not due to airway resistance, but rather low FVC (FEV1/FVC ratio normal or high)
- >0.7 (severe restriction can increase ratio >0.8
Where is the FEV1 on a flow volume curve/loop?
In positive flow roughly a little left of RV on the big chunky loop
