Mechanics of Breathing Flashcards
What is meant by compliance of the lungs?
The sketchiness of the lungs.
What is meant by higher compliance of the lungs?
It is easier for the lungs to stretch
What is meant by lower compliance of the lungs?
It is more difficult to stretch
Give some situations in which the lungs experience decreased compliance.
- Fibrosis
- Obesity/pregnancy
- Asbestos
What is the function of surfactant?
Present within alveoli, surfactant reduces surface tension by disrupting hydrogen bonds.
What is the name of the important protein in surfactant?
Protein A
What cell produces surfactant?
Type 2 pneumocyte
What is Laplace’s law?
Essentially the bigger the bubble within the lungs, the lower the pressure the bubble is under.
Explain why, although Laplace’s law would suggest the smaller alveoli would collapse as they are at higher pressure than the larger alveoli, that this is in fact not the case.
Because surfactant in the little alveoli is less effective as they increase in size, surface tension also increases and so the pressure stays high and prevents them collapsing.
Define atelectasis.
Parts of lung collapsing.
Why do babies born prematurely often experience respiratory distress syndrome?
They have very little surfactant, therefore the lungs are very stiff due to the high surface tension and they have few, large alveoli.
What is the treatment for premature babies born with respiratory distress syndrome (RDS)?
Nasal tubes that provide surfactant
TRUE OR FALSE:
Smaller tubes have high flow resistance.
True
Where is the highest resistance found within the respiratory system?
Upper airways as the numerous branching points further down increases the number of airways in parallel. This therefore compensates for the increase in resistance as the air passes down.
Explain why, in obstructive airway diseases such as asthma and chronic bronchitis, inspiration is ok however expiration is a problem.
Expiration is a problem because resistance increases much earlier in expiration
