ch 3

Question 1

why are there pressure gradients in the lungs

Answer 1

*driving airflow in and out, gas flows down gradient, pulmonary ventilation, facilitating breathing
*air flows from high pressure to lower pressure
*pressure gradient=0 no airflow
*alveolar/intrapulmonary pressure

Question 2

explain transrespiratory pressure

Answer 2

(Prs)=PA-Pao
*causes gas to flow into and out of lungs
*powers ventilation, drives airflow during breathing
*inhale (-) pull air in
*exhale(+) push out air

Question 3

explain transpulmonary pressure

Answer 3

PL=PA-Ppl
*distends the alveoli open
*determine alveolar volume(lung)
*pressure gradient “across the lung” inside alveoli to outside surface of lungs
*difference b/w alveolar pressure inside lung and plueral pressure space around the lungs.
*PL decrease causes alveoli to collapse Increase causes alveoli to inflate
*holds lung open against elastic recoil

Question 4

explain transthoracic pressure

Answer 4

Pw=Ppl-Pbs
*reflection of chest wall recoil
*transmural pressure or pressure gradient

Question 5

explain the diaphragm role in breathing

Answer 5

*most important muscle for breathing
*inhalation-diaphragm contracts and pulls downward creating a vaccum resulting in air filling space
*exhales-domeshape/relaxed

Question 6

Inspiratory reserve volume

Answer 6

3000mL
*extra air inhaled after normal breathing

Question 7

Tidal volume (VT)

Answer 7

500mL
*normal breathing

Question 8

expiratory reserve volume

Answer 8

1100mL
*extra air forced out after normal breath out

ie blowing out candles

Question 9

residual volume

Answer 9

1200mL
*air stays in lungs no matter what to keep alveoli from collapsing completely

Question 10

inspiratory capacity

Answer 10

tidal+inspiratory= 3500mL
*everything yout can inhale starting from normal breath in to out

Question 11

Functional residual capacity

Answer 11

expiratory+residual v.=2300mL
*Left in lungs after normal exhalation
*keeps O2 in blood b/w breathes

Question 12

vital capacity

Answer 12

4600mL
*Inspiratory+tidal+expiratory
*total amount of air move in&out of lungs/ deepest breath in to deepest breath out

Question 13

total lung capacity

Answer 13

5800mL
tidal+insp+expi+residual
*full capacity of lungs

Question 14

MIP
(Maximum inspiratory pressure)

Answer 14

how strong muscles are that pull air into lungs
*normal:
Female:-92cmH2O
Male:-126cmH2o

*severe: MIP>-20 (ie -15,-10)

Question 15

MEP
(maxium expiratory pressure)

Answer 15

how strong muscles are when pushing air out
*Normal MEP
female:151
Male: 229

*severe: MEP<50

Question 16

explain elasticity

Answer 16

recoil force
* lungs natural tendency to recoil or snap back to its original shape after being stretched
*high elastance-lung is stiff&hard to inflate=low compliance
*low elastance-lungs are stretchy & easy to inflate so high compliance ( lost recoil)

Question 17

explain compliance and what is normal lung compliance (CL)

Answer 17

Normal=100mL
*how easily a lung can expand
*measure of lungs opposition to inflation.
*change in lung volume produced by pressure change
*high comp=lungs expand w/little pressure
*low comp=lungs require more pressure to expand lungs are stiff& difficult to inflate

Question 18

breathing pattern for someone with high elastance,low complaince

Answer 18

rapid&shallow

Question 19

breathing pattern for someone with low elastance,high compliance

Answer 19

slower&shallow

Question 20

disease with high elastance ,low compliance

Answer 20

pulmonary Fibrosis- stiff scarred lungs, more pressure needed to fill/expand lungs
*descreased FRC

Question 21

disease with low elastance, high compliance

Answer 21

emphysema- unable to recoil due to over inflation, elastic fibers are destroyed, easily inflated but cant return to normal shape (floppy ballons)
*increased FRC

Question 22

what is the realtionship b/w elastance and compliance

Answer 22

more elastance=less compliance

less elastance=more compliance

Question 23

what is the function of surfactant in the lungs

Answer 23

*reduce surface tension in alveoli especially smaller alveoli
*type ll lamellar bodies
*reduce WOB
*keep alveoli from collapsing, not enough alveoli will collapse

RDS-babies lack surfactant

Question 24

explain airway resistance (Raw)

Answer 24

refers to resistance to airflow in the respiratory system due to friction
*frictional resistance-resistance to gas flow
*more Raw=more resistance (asthma, COPD)

Question 25

what % is the upper airway total Raw

Answer 25

50%

Question 26

what type of flow is in the upper and lower airway

Answer 26

upper(trachea,bronchi)-turbulent (choatic flow) lower(bronchioles,distal air space)-laminar (smooth airflow)

Question 27

what is peak airway pressure (Ppeak)

Answer 27

*highest pressure reach when pushing air in *total of lungs elastic recoil and the airway resistance

Question 28

what is plateau pressure (Pplat)

Answer 28

*pressure left after airflow stops. stretch in the lungs&chest wall If too High can lead to stretch injuries in the lungs like barotrauma

Question 29

causes of air-trapping and auto PEEP

Answer 29

incomplete exhalation before next breath

Question 30

explain the breathing pattern of a COPD and asthma exacerbation PT. If the PT was placed on a ventilator, what adjustment would be made to make the patient more comfortable?

Answer 30

COPD&Asthma take longer to exxhale due to narrowing of airway, resulting in airtrapping and over use of accessory muscles, you would want to try to extend the exhalation time by lowering RR