L12-13 Mechanics of Breathing and Gas Exchange

Question 1

define compliance

Answer 1

Ease with which lungs can be inflated

Question 2

compliance formular

Answer 2

change in vol/change in press

Question 3

what is compliance dependant on

Answer 3

• lung volume + size (high vol= low com)
• elastic recoil of lungs + chest
• surface tension

Question 4

compliance in restrictive and obstructive diseases

Answer 4

r= low com
o= high comp

Question 5

what does surfactant do

Answer 5

• Larger alveolar
o gas flows down pressure gradient down path of least resistance // would naturally flow to bigger alveoli
o // surfactant (secreted by alveolar type ii cell)
• Lines + reduces pressures
o = even gas flow

Question 6

which two forces keep alveolar open

Answer 6

transmural pressure grad + pulmonary surfactant

Question 7

which two forces keep alveolar closed

Answer 7

pulmonary elasticity + alveolar surface tension

Question 8

other than compliance, what also effects air flow

Answer 8

resistance

Question 9

chief site of resistance in airway

Answer 9

bronchi

Question 10

name 2 bronchodilators + receptors

Answer 10

• Albuterol, Epinephrine → ß2 adrenergic receptors)

Question 11

name 2 bronchoconstri

Answer 11

• Environmental insults

Ach

Question 12

explain lungs being ‘half full’

Answer 12

o RV prevent lungs from collapsing → less work to inflate lung
o RV ensures continuous gas exchange

Question 13

spirometry diff in normal vs ob + res

Answer 13

ob= (dec ERC + sloped ex
res= dec IRC

Question 14

fractional gas of O + CO2

Answer 14

O= 0.21
CO2= 0.0004

Question 15

PIO2 formula

Answer 15

(Pb- PH20 (47)) x 0.21

= 150ml

Question 16

alveolar air o2 mmHg

Answer 16

104

Question 17

alveolar air CO2 mmHg

Answer 17

40

Question 18

what does alveolar Po2 depend on

Answer 18

o Alveolar ventilation- how much air you get into lungs

o Metabolism- oxygen consumption

Question 19

factors affecting diffusion capacity (DL)

Answer 19

1. Surface Area
2. Respiratory Membrane Thickness
   - O.6um
3. PP Difference of O2 & CO2
   • CO2 lower gradient as more soluble than oxygen // don’t need as large
4. Diffusion Coefficient (D) of Gas
   - CO2 more sol

Question 20

VGas formula

Answer 20

= A/T xD(p1- p2)

Question 21

when does full Hb saturation occur

Answer 21

1/3 cap length

Question 22

diffusion amount diff b/w o2 and co2

Answer 22

o= 40 >104
c02 = 40 >45

Question 23

what is the

Answer 23

Hb-O2 Dissociation Curve

Question 24

effects on the Hb-O2 Dissociation Curve

Answer 24

• exercies= (uses o2 so po2 dec= offloading
• temperate
• pco2 + ph

Question 25

what is the bohr effect

Answer 25

ow pH lowers affinity off combination

Question 26

haldance effect

Answer 26

deoxygenated blood carries more CO2

Question 27

chloride shift

Answer 27

when negative bicarbonate moves out of cell, to maintain electrical = Cl moves into cell

Question 28

alveolar gas equation

Answer 28

PaO2= Pio2 - (paco2(40)/rq)

Question 29

RQ=

Answer 29

0.8