Lecture 17: The work of breathing Flashcards
What are the two opposing forces that must be overcome to take a breath?
Stiffness of the lungs
and
Resistance of the airways to the lungs
What can lung stiffness be related to?
Lung stiffness is related to Compliance
Healthy lungs are very compliant
Thickening and scarring of the alveolar membranes
Can arise from chronic inflammation or exposure to industrial chemicals, this results in stiffer lungs that are less compliant
How do the lungs over come surface tension from fluids surrounding the lungs and alveoli fluid?
Alveoli produce surfactant to disrupt surface tension
Relieves surface tension and allows the alveoli to expand
during a breath
Failure to produce adequate surfactant results in difficulty
in expanding the lungs and reduced oxygen intake
Premature infants don’t produce surfactant, resulting in
respiratory distress syndrome (RDS)
Which of the following statements about the work of
breathing is NOT CORRECT?
A. The chest and lungs expand during inhalation.
B. The alveoli release surfactant to overcome surface
tension from the surrounding fluid.
C. Low compliance of the lungs allows them to more
easily fill with air.
D. Thickening and scarring of the alveolar membranes
can lead to a reduction in lung compliance.
C
High compliance of the lungs allow them to fill easily with air, not low
What is Obstructive versus restrictive issues with breathing?
Obstructive = resistance to airflow eg. asthma or chronic bronchitis
Restrictive = Reduced lung compliance eg. fibrosis or insufficient surfactant release
What does spirometry measure?
A spirometer measures volume inspired / exhaled
Can measure how much and how fast you breathe
Can you label a spirometry trace????
Yes Yipee
Noooooooooooo
Which of the following best describes the vital capacity?
A. Volume remaining in lungs if they collapsed
B. Volume of air moved in and out during normal quiet
breath
C. Total volume in lungs when you’ve filled them to max
D. Volume of air you can shift in and out of your lungs
D
