3 lung volumes/airway function Flashcards Preview

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Flashcards in 3 lung volumes/airway function Deck (15)
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1
Q

ventilation? oxygenation?

A

V = exchange of gas b/w lung and environment. O = addition of oxygen to blood.

2
Q

airway obstruction is defined by?

A

decrease in ration of FEV1/FVC < 88% predicted = < 0.75 if young, or < 0.70 if old

3
Q

obstruction can be ___, ____ or ______. examples of obstruction?

A

fixed, reversible, partially reversible. COPD (emphysema, chronic bronchitis), sarcoidosis, long standing asthma, cystic fibrosis

4
Q

restriction definition

A

decreased total lung capacity (lung volume at max. volume)

5
Q

restrictive defects are caused by? (3 categories)

A

stiff lungs that are difficult to inflate (pulm. fibrosis, thickening of visceral pleura, pulm. edema, etc.) chest wall disease (obesity, structural changes, resp muscle weakness), pleural space disease (pneumothorax, pleural effusion)

6
Q

obstruction vs. restriction: lung volumes?

A

obstruction = higher volumes. restriction = lower.

7
Q

FRC stands for? determined by balance of? def?

A

functional residual capacity: balance of lung elastic recoil (wants to collapse) and chest wall recoil (wants to spring out). = vol of gas in lungs when no work being done by muscles

8
Q

size of airways at TLC vs. FRC

A

airways bigger at TLC (so enlarge during inspiration). smaller at FRC, they get smaller when you breathe out.

9
Q

definitions of FRC? TLC? RV? VC?

A

FRC: vol of lungs at start of a normal tidal volume inspiration. TLC= max lung volume, RV= min. VC = max volume of air that can be exhaled after a full inspiration to TLC.

10
Q

how does obstruction lead to hyperinflation

A

narrow and high resistance airways close during exhalation = can’t empty the lungs –> VC decreased, but FRC increased

11
Q

Palv (alveolar pressure) = ?

A

sum of Pst aka natural recoil of lungs and Ppl aka pressure outside lungs in pleural space

12
Q

what happens to FRC in obesity

A

decreased –> so decreases diameter of airways; then mistakenly thought to have airway disease

13
Q

flow equation

A

flow = pressure difference / resistance aka difference between alveolar and atm. pressure divided by total airway resistance

14
Q

flow equation: pleural pressure depends on?

A

effort

15
Q

FEV1 is what? depends on what?

A

volume exhaled forcibly in 1 second: affected by resistance in larger airways, and is effort dependent