pk 2 - Lung Mechanics - Compliance Flashcards
Draw table showing lung volumes in average adult male
TLC - 6.0L VC = 4.8, RV = 1.2 IC = 3.3, FRC = 2.7 IRV, TV = 500ml, ERV, RV Don't worry about knowing all values
Air moves into and out of the lungs according to ………… Law - whereby ……… changes caused by the ………… changes brought about by …………. ………….. leads to …………
Boyle's pressure volume thoracic expansion airflow
Respiratory muscles do work to:
1.
2.
stretch the elastic compenents of the respiratory system (moving lung tissue)
overcome resistance to flow
How are the thoracic cage and the lung coupled?
They are not coupled through any anatomical structure but are linked only through the generation of a negative intrapleural pressure. This aries as a consequence of elastic recoil of both the lungs and the chest wall.
Lung-thorax coupling is determined by the ……… properties of the lungs and thoracic cage
elastic
Airflow occurs as a consequence of small changes in ………. pressure relative to …………. pressure and this is brought about by changes in thoracic cage volume that are coupled to change in …… volume brought about by negative intrapleural pressure
aleveolar
atmospheric
alveolar
At FRC, the lung and chest walls exert forces on each other that are …….. and ………
Actual touching between the parietal and visceral pleura does not occur because of ……… forces between several layers of …………. absorbed on mesothelial surfaces carrying charges of the same sign
equal, opposite
repulsive
phospholipids
Draw quick sketches of these 5 graphs, all with time on the x-axis and starting with inspiration - volume - airflow - recoil pressure - alveolar pressure - intrapleural pressure Which graphs look the same?
volume - increases then decreases
airflow and alveolar pressure are the same
recoil pressure and intrapleural pressure are the same
- Airflow profile follows that of….
- During expiration Ppl and PA …..
- PA is always …….. than intrapleural pressure
- In quiet breathing, intrapleural pressure is always …… whilst alveolar pressure moves from …… to ………
- Airflow ceases when ………. is 0
- At high ventilation, intrapleural and alveolar pressure changes are ……….
- intrapleural pressure is positive during ……
alveolar pressure rise greater negative, negative to positive alveolar pressure increased coughing/sneezing
The elasticity of the lungs and chest wall is quantified by their …….. - i.e. the change …….. for a particular ………
Normally the compliances of lung and chest wall are …….
compliance
volume, pressure
similar
The lungs and chest wall have different …………. volumes (i.e. the volumes they contain at zero ….. …….) that they will move to in a ……………………
equilibrium
distending pressure
pneumothorax
The equilibrium volume the respiratory system is at ……., which is where the lung and chestwall recoil pressures are …… and ………. , and is therefore the volume which point the respiratory system will move to when the ……… is open and all repsiratory muscles are …………
FRC
equal and opposite
glottis
relaxed
What is the equation for compliance?
What are the units?
Compliance = change in volume / change in pressure
L/kPA
- Compliance is greatest around …..
- Lung compliance lowest towards ……
- Normal lung compliance is around ….L/kPa
- Lung and thoracic cage compliance …… around …..
- Specific compliance = ………. / ………… This is useful to compare objects of different size
- Equilibrium volume is found at …… distending pressure
- Chestwall compliance curve crosses at ……… ………… ……
- FRC
- TLC
- 1.5
- similar, FRC
- compliance/FRC
- zero
- zero distending pressure
The total system is …….. as stiff as its components
twice
