Section 5 Lecture 3 Flashcards
True or False? Inspiration is active at all lungs volumes.
F. not for FRC
When does expiration because active?
exercise, cough, vomiting, ling disease that increases airway resistance, speaking and singing
True or False? The more a muscle stretches the more force it can generate.
F. more stretch = less force
What results if the recoil > chest wall force?
FRC decreases
What results if the muscles of contraction are weak/
FRC decreases (why? I would think it would increase)
an instrument for measuring changes in volume in lungs:
plethysmograph
What can lead to premature airway closure?
plethysmograph > helium (?)
Transpulmonary pressure is aka:
transmural pressure
Transpulmonary pressure =
alveolar - pleural pressures
P (w) is:
Transmural pressure across the chest wall
P (w) =
pleural - barometric pressure
P (rs) (respiratory system) =
transmural pressure surrounding lungs + transmural pressure across chest wall OR alvelor - barometric pressure
What does a spirometer tracing show?
lung volumes and capacities
FRC =
residual volume + ERV
Vital capacity =
ERV + Tidal volume + IRV
Inspiratory capacity =
Tidal volume + IRV
Avg tidal volume:
500 mL
Avg IRV:
3000 mL
Avg ERV:
1100 mL
Avg vital capacity:
4600 mL
Pulmonary volumes, men vs. women:
5800 vs. 4200 (the graph was for a man)
Primary determinants of lung volume:
sex, age, height (20% variability)
Avg RV/ TLC ratio:
25%
Elevated RV/ TLC ratio secondary to RV elevation:
obstructive pulmonary diseases (chronic bronchitis)
Elevated RV/ TLC ratio secondary to TLC decrease:
restrictive lung diseases (pulmonary fibrosis)
Factors affecting the RV/ TLC ration:
elastic recoil of lung, compliance, muscle strength of inspiratory muscles, recoil of the chest wall
How is FRC affected if the chest wall muscles are weak?
FRC decreases, lung elastic recoil > chest wall muscle force
How is FRC affected if there is an airway obstruction?
FRC increases (premature airway closure)