Breathing Quantified Flashcards
What is a spirometer?
device that allows plotting lung volume against time (spirogram)
spirometer cannot measure all lung volumes/capacities (TLC and RV)
How many lung volumes and capacities are there?
there are 4 static lung volumes, and combination of these give rise to 4 lung capacities
What are the 4 static lung volumes?
- tidal volume (TV)
- inspiratory reserve volume (IRV)
- expiratory reserve volume (ERV)
- residual volume (RV)
What are the 4 lung capacities?
- inspiratory capacity (IC)
- functional residual capacity (FRC)
- vital capacity (VC)
- total lung capacity (TLC)
What is tidal volume (TV)?
volume of what you normally breathe in and out
What is inspiratory reserve volume (IRV)?
volume above what you normally breathe in
What is expiratory reserve volume (ERV)?
volume below what you normally breathe out
- after taking a single normal breath in, exhale all the way – ERV is what you can squeeze out
What is residual volume (RV)?
volume you couldn’t breathe out – still some air left in lungs
- maximum expiration
What is inspiratory capacity (IC)?
IC = TV + IRV
breathe all the way in, then exhale back to end of normal breath
What is functional residual capacity (FRC)?
FRC = ERV + RV
end of normal breath
What is vital capacity (VC)?
total volume of air that can be displaced from lungs by maximal expiratory effort
fill lungs completely, then empty completely
What is total lung capacity (TLC)?
TLC = IC + FRC
amount of air you breathe between total inspiration and total expiration possible
maximum inspiration
What are factors that influence static lung volumes? (4)
- height
- gender
- age
- ethnicity
How does height influence static lung volume?
taller = larger lung volume
How does gender influence static lung volume?
male = larger lung volume
How does age influence static lung volume?
- lung volumes increase with development until ages 20-25 year old
- older = higher RV and FRC
- older = lower VC, resulting in gas trapping
- changes are due to stiffening of chest wall with onset of senescence
- NOT due to increasing compliance in lungs
How does ethnicity influence static lung volume?
differences partly due to body build (ie. relative length or width of chest wall)
What do restrictive diseases do?
restrict inspiration
lung volumes reduced – difficulty getting air into lungs due to changes in mechanics of lungs or chest wall
What are some restrictive diseases?
- pulmonary fibrosis (stiff lungs)
- ankylosing spondylitis (stiff chest wall)
- kyphoscoliosis (stiff chest wall)
How does pulmonary fibrosis affect the lungs?
stiff lungs = elastance increases, compliance decreases → can’t stretch → problems getting air in
What do obstructive disease do?
limit air flow out of lungs during expiration
difficulty getting air out of lungs, due to resistance increasing or compliance increasing
What are some obstructive diseases?
- chronic obstructive pulmonary disease (COPD)
- asthma
- chronic bronchitis
- emphysema