Lung Volumes and Lung Dz

Question 0

Intrapleural Pressure in pleural cavity is > or < than ATM?

Answer 0

less than ATM (756): keeps lungs expanded and chest wall from overexpanding
So does this mean when intrapleural pressure is < ATM (also < lungs), then lungs are expanded?

Question 1

Pressure inside lungs equals

Answer 1

ATM (760)

When PrLung< Patm, air rushes into lungs (inhale)
When Plung>Patm, air rushes out of lungs (exhale)

Question 2

• 5 cm H2O in pleural cavity is > ATM by 5 cm ???
  Lung elastic forces want to collapse
  chest wall elastic forces want to expand
  Lung “elastic forces” (recoil = return back) are due to:
  1) collagen and elastin in interstitial matrix
  2) surface tension forces in alveoli
  Chest wall recoil/elastic forces are due to:
  1) tendons and muscles between ribs

Answer 2

Antagonistic action of these forces generates (-) Intrapleural Pressure which counteracts elastic force (recoil): (lungs wanting to collapse and chest wall wanting to expand ??)

Question 3

Atelectasis

Answer 3

absence of gas from all or part of a lung due to a failure of expansion

Question 4

What happens if the chest wall (thoracic wall is covered with parietal pleura) is punctured

Answer 4

Pneumothorax: lung collapses, chest wall springs away (because chest wall elastic forces/recoil favor expansion (due to tendons/muscles btw ribs)
???Is it bc air rushes into intrapleural sack and Pis raises and can no longer oppose the recoil of chest wall and lung???

Question 5

Diaphram contract more during

Answer 5

excercise

Question 6

When inspire: Vol chest cavity (lungs????) increases and lowers Pip causing lungs to expand
Increase in volume causes decrease in intrapleural pressure
Muscles involved:

Answer 6

Diaphragm: when contracts, it flattens, goes down
external intercostals: elevate ribs and sternum
accessory m: SCM and scalenes : elevate chest only during excercise

Question 7

Eupnea

Answer 7

resting

Question 8

During excercise, diaphragm raises or depresses with inspiration?

Answer 8

Depresses (could up t 10 cm)

Question 9

During eupnea (resting) inspiration

Answer 9

Diaphragm derpresses 1 cm with inspiration

Question 10

Tidal Volume: Tv (500 ml)

Answer 10

Volume of air moving in and out of lungs with each breath

Question 11

Residual volume (1200 ml) (RV)

Answer 11

lung volume remaining AFTER maximal expiration.

Question 12

Vital Capacity (VC) (4500)

Answer 12

Total Lung Capacity (TLC) - Residual Volume (RV)

Maximum of what can be exhales

Question 13

Total lung capacity (TLC) (5700 ml)

Answer 13

Vital Capacity (VC: all that can be exhaled) + Residual Volume (RV) (can’t be exhaled)

Question 14

Expiratory reserve volume (ERV) (1000 ml)

Answer 14

additional air that can be exhaled after a normal exhalation

Question 15

Functional residual capacity (FRC 2200 ml)

Answer 15

Air that’s in reserve: part can be exhaled after normal exhale and part can’t ever be exhales
Expiratory reserve volume (ERV: additional air that can be exhaled after normal) + residual volume (RV: can’t exhale at all)

Question 16

Restrictive lung disease

Answer 16

Lung and chest walls can’t expand as well: need greater change in intrapleural pressure (Pip) to produce to produce the same change in volume (to push air out or breath in)
Which each inhale or exhale effort, lung volume is reduced
Examples: pulm fibrosis, partial resp muscle paralysis, massive obesity, rib fusion

Question 17

Pulm fibrosis is an example of

Answer 17

Restrictive Lung Dz

Question 18

Restrictive Lung Dz

Answer 18

ALL lung volumes REDUCED
(Vt: air in and out) may be unaffected
Reduced:
- TLC (total lung volume) because lungs can’t be expanded
- RV (residual volume: can’t exhale)
But: since both are reduced, the ratio or RV/TLC is NORMAL (0.2-0.3)

Question 19

Obstructive Lung Dz is due to

Answer 19

increase in airway resistance
Increase:
residual volume (RV) and functional residual capacity (FRC: RV+ERV) (and TLC Total lung volume if chronic)
e.g:
asthma - airways constrict and mucus section increases
bronthitis - inflammation of bronchi, increase mucus and hypertrophy of mucus glands and over time walls: lumen gets smaller
emphysema - alveolar degeneration, increased compliance, airways close early when exhale
COPD - bronchitis and emphysema (chronic obstructive pulmonary dz)