Chapter 16 Study Questions (Pt. 4) Flashcards
what is surfactant? (what is it made of and how is it made?)
made of proteins and phospholipids
made by type 2 alveolar cells
what is the role of surfactant in lung function?
disrupts surface tension to prevent alveolar collapse
what is surface tension?
when H2O binds to itself and other surfaces
what force creates surface tension?
hydrogen bonding from water molecules
how does surfactant reduce surface tension?
interferes with hydrogen bonding in water-water and water-surfaces
in the absence of surfactant, why do alveoli collapse?
water within the alveoli are pulled closer to each other due to surface tension and the alveolus collapses
how does surfactant prevent the loss of smaller alveoli?
disrupts hydrogen bonding, making it easier for smaller alveoli to expand and contract
smoking destroy airway cilia. how do airway cilia affect lung function?
damage or limit ability to move foreign substances out of the conducting zone
smoking causes inflammation. how does inflammation affect lung function?
- stimulate WBC to destroy healthy tissue
- cause airways to narrow
- damage ability to do gas exchange
smoking promotes collagen synthesis. how does collagen synthesis affect lung function?
- increase distance between alveoli, accumulate in place of alveoli in lung fibrosis
smoking destroys elastin. how does destruction of elastin affect lung function?
elastin allows for lung recoil. destroying elastin decreases recoil, meaning that elastin doesn’t snap back into place as well as it used to.
a person with COPD must breathe harder and faster to maintain the same resting lung tidal volume as a healthy person. why?
- loss of alveoli
- airways become inflamed and narrow
- person must work harder because they are capturing a smaller amount of air (2.5 vs. 5 liters)
how does COPD affect lung inspiratory reserve volume? why?
decreases.
- scar tissue reduces compliance
- scar tissue reduces ability to inhale
how does COPD affect lung expiratory reserve volume? why?
decreases.
- loss of elastin = harder to exhale
what does “compliance” mean in ventilation?
how easy it is to inflate the lungs
what are the main inspiratory muscles during quiet breathing?
diaphragm; external intercostals
what are the main expiratory muscles during quiet breathing?
relaxing the inspiratory muscles: diaphragm and intercostals
what are the main inspiratory muscles during active breathing?
diaphragm; external intercostals
what are the main expiratory muscles during active breathing?
internal and innermost intercostals + abdominal muscles/wall
how does lung compliance facilitate ventilation?
smaller change in pressure is needed to bring in a given volume
how does lung recoil facilitate ventilation?
smaller change in pressure is needed to bring in a given volume
what does “recoil” mean in ventilation?
how easy it is for lungs to snap back into place
