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Flashcards in Resp - Respiratory Mechanics Deck (65)
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1

muscles of inspiration

diaphragm (75%)
external intercostals (25%)

2

accessory inspiration muscles

scalenes (raise rib 1/2)
sternocleidomastoid (raise sternum)

3

muscles of expiration (active)

abdominal wall
internal intercostals

4

causes for difficulty inspiring

scar tissue
reduced surfactant
mucous
fluid

5

causes for difficulty expiring

emphysema

6

point where laminar --> turbulent

reynolds # > 2000

7

conditions where turbulence likely occurs

velocity high
radius high

8

Reynold's number

Re = 2rvd/n

9

Ohm's law (airflow)

F = delta P/R

10

Poiseuille's law

R = 8L(viscocity)/pi(radius^4)

11

Poiseulle's law take away

smaller the airway, greater the R (reduce r by 50% increase R x 16)

12

site of most airway R (+why)

medium sized bronchi
smaller than large (up R) and in series rather than parallel (smaller ones in parallel)

13

factors increasing resistance

turbulent flow
small radius
lung volume decreasing
bronchial SM contraction
gas density elevated (SCUBA)
forced expiration

14

causes of bronchoconstriction

allergy
mucous, airway collapse
PNS during relaxed state (Ach on muscarinic)
low CO2

15

causes of bronchodilation

SNS
*Epi (beta-2)
*CO2 up

16

forced exhalation

PA drives air out
PA = Pip + P elastic recoil
further from alveoli, less recoil
exhaling air hits R, loses P
EPP

17

equal pressure point

when Pairway = Pip
if Pip > Pairway --> collapse
(EPP @ cartilage for healthy people)

18

emphysema and forced expiration

alveoli have lost elastic recoil
PA is lower, EPP happens closer to alveoli, compression of airway

19

chronic obstructive pulmonary disease (diseases)

asthma
chronic bronchitis
emphysema

20

emphysema mech

1. irritation --> many macs, release trypsin
usually alveoli release antitrypsin (but too many macs to fight)
2. breakdown of alveolar walls
3. down recoil, collapse smaller airways

21

pulmonary function tests

spirometry
lung vol measurement
diffusion capacity for CO
arterial blood gases

22

tidal volume (TV)

V in or out in quiet resp
~500 ml

23

inspiratory reserve volume (IRV)

extra V can be inspired after quiet inspiration

24

expiratory reserve volume (ERV)

extra V can be expired after quiet expiration

25

inspiratory capacity (IC)

max V in after quiet expiration (TV + IRV)

26

vital capacity (VC)

max V in after max expiration (IRV + TV + ERV)
~ 4800 ml

27

residual volume (RV)

min air remaining in lungs after max expiration

28

functional residual capacity (FRC)

V in lungs after quiet expiration (ERV + RV)

29

total lung capacity (TLC)

max V lungs can hold (VC + RV) ~6000 ml

30

abnormal spirometry results (obstructive)

can't get air out
RV up
up RV, FRC, TLC
--> slow flow, hyperinflation, down recoil